US 4,348,320 AGrant
Substituted Azetidiones
Issue Date:1982-09-07
•6 Claims
Abstract
Disclosed are substituted azetidinones (1) which are useful in the preparation of 1-carba-2-penem-3-carboxylic acids (I): ##STR1## wherein R is hydrogen or a blocking group and R.sup.1, R.sup.2 and R.sup.3 are, inter alia, independently selected from the group consisting of hydrogen, alkyl, aryl, and aralkyl. Such 1-carba-2-penem-3-carboxylic acids and their pharmaceutically acceptable salt, ester and amide derivatives are useful as antibiotics.
Metadata
Assignee
- Merck & Co., Inc.
Inventors
- F. Aileen Bouffard
- Burton G. Christensen
- David B. R. Johnston
Application Information
Application Number:US 1799223
Filing Date:1980-08-20
Priority Date:1976-11-19
Art Unit:122
Classifications
IPC:
C07D20508C07D48704
Field of Search:
260542239 AL429;442
Patent Drawings
This patent does not have any drawings.
Description
BACKGROUND OF THE INVENTION
This invention relates to certain substituted azetidinones having the structure 1: ##STR2## wherein R.sup.1, R.sup.2, R.sup.3 and R are defined below. Such azetidinones are useful in the preparation of certain substituted 1-carba-2-penem-3-carboxylic acids (I) and their pharmaceutically acceptable salt, ester and amide derivatives which are useful as antibiotics: ##STR3## Such 1-carba-2-penem-3-carboxylic acids are disclosed and claimed in co-pending, concurrently filed, commonly assigned, U.S. Patent Application Ser. No. 743,363, filed Nov. 19, 1976, now abandoned. Relative to 1 and I, R is hydrogen or an acyl or triorganosilyl blocking group and R.sup.1, R.sup.2 and R.sup.3 are independently selected from the group consisting of hydrogen substituted and unsubstituted: alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, alkylcycloalkyl, aryl, aralkyl, aralkenyl, aralkynyl, heteroaryl, heteroaralkyl, heterocyclyl and heterocyclylalkyl wherein the substituent or substituents relative to the above named radicals are selected from the group consisting of amino, hydroxy, alkoxyl, mercapto, alkylthio, arylthio, sulfamoyl, amidino, quanidino, nitro, chloro, bromo, fluoro, cyano and carboxy; and wherein the hetero atom in the above named heterocyclic moiety is selected from the group consisting of oxygen, nitrogen and sulphur.
This invention also relates to the pharmaceutically acceptable salt, ester and amide derivatives of the compounds of the present invention identified by structure (I), above.
This invention also relates to processes for the preparation of such compounds (I); pharmaceutical compositions comprising such compounds; and to methods of treatment comprising administering such compounds and compositions when an antibiotic effect is indicated.
There is a continuing need for new antibiotics. For unfortunately there is no static effectiveness of a given antibiotic because continued wide scale usage of any such antibiotic selectively gives rise to resistant strains of pathogens. In addition, the known antibiotics suffer from the disadvantage of being effective only against certain types of microorganisms. Accordingly the search for new antibiotics continues.
Thus, it is an object of the present invention to provide a novel class of antibiotics which are useful in animal and human therapy and in inanimate systems. These antibiotics are active against a broad range of pathogens which representatively include both gram positive bacteria such as S. aureus. Strep. pyogenes. Pseudomonas, and B. subtillis, and gram negative bacteria such as E. coli, Proteus morganii, Serratia and Klebsiella. Further objects of this invention are to provide chemical processes for the preparation of such antibiotics and their non-toxic pharmaceutically acceptable salts; pharmaceutical compositions comprising such antibiotics; and to provide methods of treatment comprising administering such antibiotics and compositions when an antibiotic effect is indicated.
DETAILED DESCRIPTION OF THE INVENTION
The 1-carba-2-penem-3-carboxylic acids (I, above) are conveniently prepared by the following scheme: ##STR4## wherein R.sup.1, R.sup.2 and R.sup.3 are as defined; R and R' are readily removable blocking groups; R' may also be a pharmaceutically acceptable ester moiety. Typically, the blocking group R is an acyl such as a lower alkanoyl, aralkylcarbonyl or the like such as acetyl, bromo-t-butoxycarbonyl, benzyloxycarbonyl, formyl, trifluoroacetyl and the like or a trialkylsilyl such as trimethylsilyl or t-butyl dimethylsilyl group; and typically the blocking group R' is substituted or unsubstituted alkyl, aralkyl, alkenyl, or the like such as benzyl, p-nitrobenzyl, o-nitrobenzyl, pivaloyloxymethyl, bromo-t-butyl and the like.
In words relative to the above reaction diagram, a suitably substituted azetidinone (1) is reacted with a glyoxalate ester such as benzyl glyoxalate to form the corresponding 1-(benzyloxycarbonylhydroxymethyl) azetidinone (2). The reaction 1.fwdarw.2 is conveniently carried out in a solvent such as benzene, toluene, xylene and the like at a temperature of from about 25.degree. C. to reflux for from 2 to 10 hours. There is no criticality as to the precise identity of the solvent, provided only that it adequately solubilizes the reactants and be inert or substantially inert to the desired course of reaction. The halogenation reaction 2.fwdarw.3 may be conducted by any of a variety of well-known halogenation means. Suitable reagents include: SOCl.sub.2, POCl.sub.3, oxalyl chloride and the like. A preferred means of chlorination involves treating 2 in a solvent such as tetrahydrofuran (THF), ether, CH.sub.2 Cl.sub.2 and the like with thionylchloride in the presence of 1 to 2 equivalents (relative to the thionylchloride) of a base such as pyridine, triethylamine, quinoline and the like. Typically, the reaction is conducted at a temperature of from -30.degree. to 25.degree. C. for from 0.5 to 1 hour. The resulting 1-(benzyloxycarbonylchloromethyl)-azetidinone species, 3, is isolated, if desired, by conventional procedures for later reaction, 3.fwdarw.4. The intermediate 4 is prepared from 3 by treating 3 in a solvent such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), THF, dimethoxyethane (DME) and the like with 1 to 1.5 equivalents of a phosphine such as triphenylphosphine, tributylphosphine, triethylphosphine, tris-(2-cyanoethyl)phosphine or the like. Typically the reaction is conducted under a nitrogen atmosphere at a temperature of from -20.degree. to 25.degree. C., for from 0.5 to 2 hours. The reaction 4.fwdarw.5 may be achieved by any of a variety of well-known deblocking procedures such as hydrolysis or hydrogenolysis. A particularly convenient means for the deblocking, 4.fwdarw.5, is by an alcoholysis procedure comprising treating 4 in a lower alkanol such as methanol, ethanol, or the like in the presence of 0.1 to 1.4 equivalents of the corresponding alkali metal alkoxide such as sodium methoxide or the like; typically the reaction is conducted at a temperature of from 0.degree. to 25.degree. C., for from 0.5 to 2 hours. The ring closure reaction 5.fwdarw.7 proceeds via the oxo intermediate 6 and is achieved by treating 5 with an equivalent of an oxidizing system such as 1:1 mixture of dimethylsulfoxide (DMSO) and acetic anhydride (Ac.sub.2 O); other oxidizing systems include cyclohexylcarbodiimide in DMSO, and Cro.sub.3.2(pyridine) in CH.sub.2 Cl.sub.2, for example. Typically, the closure step 5.fwdarw.7 is conducted at a temperature of from about 0.degree. to 100.degree. C. for from 0.25 to 24 hours in the oxidative system (DMSO/Ac.sub.2 O) described above or by heating (after isolation of the oxo compound 6) in a solvent such as benzene, toluene, dioxane or DMF. The carboxyl deblocking step 7.fwdarw.8 may be achieved by a number of well-known procedures such as hydrooysis, hydrogenation or photolysis of a suitable R' group. Suitable hydrogenation catalysts for deblocking include the platinum metals and their oxides such as palladium on carbon and the like; suitable solvents for the hydrogenation include methanol, dioxane/H.sub.2 O, ethanol/H.sub.2 O and the like in the presence of hydrogen at a pressure of from 1 to 50 atmosphere; the hydrogenation is typically conducted for from 5 min. to 4 hours at a temperature of about 25.degree. C. in the presence of a mild base such as sodium bicarbonate.
The glyoxalate esters 1a used to react with 1 can be prepared by oxidation of the corresponding tartaric acid diesters with oxidants such as periodic acid or lead tetra-acetate in a solvent such as THF, benzene or methylene chloride at -20.degree. to 25.degree. for 1/2 to 4 hrs. The tartarate esters are prepared from the dilithio tartarate or disodio tartarate by reaction with R'X wherein X is chloro, bromo or iodo and R' is as defined above in a solvent such as DMF or DMSO at 25.degree. to 70.degree. C. for from 4 to 48 hrs. As noted above, R' may be a readily removable carboxyl blocking group when ultimately the free acid, or salt, of I is desired; or R' may be a pharmaceutically acceptable ester moiety. Such pharmaceutically acceptable esters and amides, however, may also be prepared from the free acid or I according to the procedure of co-pending U.S. Patent Application Ser. No. 733,651, filed Oct. 18, 1976, now abandoned, which is directed to the pharmaceutically acceptable esters and amides of thienamycin and their preparation. Accordingly, for its disclosure relative to such pharmaceutically acceptable forms and their means of preparation, the above-cited application is incorporated herein by reference.
The following diagram summarizes the synthesis of this essential starting material, 1. ##STR5##
In words relative to the above diagram for the preparation of 1, the 4-(2-acetoxyvinyl)azetidine-2-one (3) is prepared by reacting chloro sulphonyl isocyanate and an acyloxybutadiene such as 1-acetoxybutadiene in a solvent such as anhydrous dimethyl ether at a temperature of from about -30.degree. C. to 0.degree. C. under a nitrogen atmosphere. The reaction intermediate 2 is converted to 3 by hydrolysis. The reduction of 3 to provide the 4-(2-acetoxyethyl)-2-azetidinone (4) is conducted by any convenient means such as hydrogenation in the presence of a catalyst such as platinum, palladium or oxides thereof under a hydrogen pressure of from 1 to 20 atmospheres in a solvent such as ethanol, ethylacetate, or the like at a temperature of from 0.degree. to 25.degree. C., for from 5 minutes to 1 hour. The 4-(2-hydroxyethyl)-2-azetidinone species, 5, is obtained from 4 by hydrolysis. The 8-oxo- 2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane species, 6, is obtained on treatment of 5 with 2,2-dimethoxypropane in the presence of a catalyst such as boron trifluoride etherate in a solvent such as methylene chloride at a temperature of from 0.degree. to 40.degree. C. for from 1 to 40 minutes. Alternatively, 5 can be treated with borontrifluoride etherate and trimethylorthoformate to give 8-oxo-2-methoxy-3-oxa-1-azabicyclo[4.2.0]octane which can be mono- or dialkylated following the procedures for 6.fwdarw.7 or 8. Alkylation of 6 provides 7. Typically, 6 is treated with a strong base such as lithium diisopropyl amide, sodium hydride, phenyl lithium or butyl lithium and the like in a solvent such as tetrahydrofuran (THF), ether, dimethoxyethane and the like at a temperature of from -80.degree. C. to 0.degree. C., whereupon the alkylating agent of choice, R.sup.1 X, is added (R.sup.1 is as described above and X is chloro or bromo; alternatively the alkylating agent may be R.sup.1 -tosylate, R.sup.1 -mesylate or an aldehyde or ketone such as acetaldehyde and the like) to provide mono- alkylated species 7. When desired dialkylated species 8 may be obtained from 7 by repeating the alkylating procedure, 6.fwdarw.7. Species 9 is obtained from 7 or 8 by acid hydrolysis. Oxidation of 9 with an oxidizing agent such as DMSO-acetic anhydride, pyridine.CrO.sub.3, cyclohexylcarbodiimide/DMSO, and the like in a solvent such as DMSO, pyridine, acetonitrile, methylene chloride, and the like at a temperature of from about 0.degree. to 25.degree. C. for from 0.5 to 12 hours provides 10 which upon treatment with the Grignard reagent R.sup.3 MgX (R.sup.3 is as defined above and X is halogen) provides 11. Typically, the alkylation reaction 10.fwdarw.11 is conducted in a solvent such as ether, THF, benzene and the like at a temperature of from -78.degree. to about 25.degree. C. at from 0.5 to about 24 hours.
The desired blocked-species 1 is obtained by treating 11 with an acylating agent such as acetyl chloride, formic acetic anhydride, trifluoroacetic anhydride and the like in a solvent such as CH.sub.2 Cl.sub.2, CHCl.sub.3, THF and the like at a temperature of from -20.degree. to about 25.degree. C. for from 0.5 to about 4 hours. The starting material 1 may be isolated for later reaction in accordance with the procedures or the present invention for the preparation of I (above).
It should be noted that in the establishment of R.sup.3 (9.fwdarw.10.fwdarw.11), the ring nitrogen may be protected by an easily removable blocking group R": ##STR6## wherein R" is acyl or triorganosilyl such as trimethylsilyl, t-butyldimethylsilyl, trifluoroacetyl, formyl, or the like. Removal of R" is accomplished by hydrolysis to provide 11 (or 1 from N-blocked 1) according to well-known procedures.
Starting material 1, may alternatively be prepared by the following scheme: ##STR7## wherein all symbolism is as previously defined.
Reaction 5.fwdarw.5a is accomplished by treating 5 with 2,3-dihydropyran in a solvent such as p-dioxane, benzene, and the like in the presence of p-toluene sulphonic acid, perchloric acid, or the like at a temperature of from 0.degree. to about 30.degree. C. The intermediate 5a may be isolated for later alkylation to obtain 7a and 8a by procedures analogous to previously described reactions 6.fwdarw.7.fwdarw.8. Intermediate species 9 is obtained from 7a or 8a by mild acid hydrolysis.
Finally, it should be noted that intermediate species 9 may conveniently be prepared for later reaction in the above scheme by internal acylation according to the following reaction: ##STR8## wherein R is acyl, ##STR9## is R.sup.1 and R.degree. is for example lower alkyl, acyl, or the like. Typically the above reaction is conducted in a solvent such as tetrahydrofuran, ether, dimethoxyethane, or the like in the presence of 1 to 2 equivalents of a strong base such as lithium diisopropylamide, sodium hydride, potassium hydride or the like at a temperature of from -78.degree. to 25.degree. C., for from 0.5 to 24 hours.
In the generic description of the present invention (1, above), the substitutents R.sup.1, R.sup.2 and R.sup.3 are preferably selected from the group consisting of hydrogen; substituted and unsubstituted: straight and branched loweralkyl having from 1 to 10 carbon atoms; alkenyl, alkynyl, having from 2 to 10 carbon atoms; cycloalkyl having from 3 to 6 carbon atoms; cycloalkylalkyl wherein the cycloalkyl moiety comprises 3 to 6 carbon atoms and the alkyl moiety comprises 1 to 10 carbon atoms; alkylcycloalkyl wherein the alkyl moiety comprises 1 to 6 carbon atoms and the cycloalkyl moiety comprises 3 to 6 carbon atoms; aryl such as phenyl and naphthyl; aralkyl such as benzyl, phenethyl and the like; heterocyclyl (saturated and unsaturated) comprising mono- and bicyclic structures having from 5 to 10 ring atoms wherein one or more of the hetero atoms is selected from oxygen, nitrogen or sulphur, such as thiophene, imidazolyl, tetrazolyl, furyl and the like; heterocyclylalkyl which comprises the immediately preceding heterocyclyl moieties and the alkyl moiety comprises from 1 to 10 carbon atoms; the substituent (or substituents) relative to the abovenamed radicals is selected from the group consisting of amino, hydroxyl, cyano, carboxyl, nitro, chloro, bromo, fluoro, lower alkoxy having from 1 to 6 carbon atoms, mercapto, perhaloloweralkyl such as trifluoromethyl, loweralkylthio, guanidino, amidino, sulfamoyl, N-substituted: sulfamoyl, amidino and guanidino wherein the substituent is loweralkyl having from 1 to 6 carbon atoms or aryl having 6-10 carbon atoms.
A particularly preferred class of compounds are those wherein R.sup.1, R.sup.2 and R.sup.3 are all hydrogen as well as those compounds wherein either R.sup.1 and R.sup.2 is hydrogen and R.sup.3 is selected from the group consisting of substituted and unsubstituted: loweralkyl having from 1 to 6 carbon atoms, alkenyl having from 2 to 6 carbon atoms, and phenyl; R.sup.1 is an .alpha.-substituted alkyl wherein the .alpha.-substituent is hydroxyl, amino or mercapto and wherein the alkyl moiety is straight or branched and comprises 1 to 6 carbon atoms; the substituents relative to the above-named preferred radicals are selected from the group consisting of hydroxyl, amino, amidino, guanidino, phenyl, mercapto, carboxyl, trifluoromethyl, loweralkylthio and loweralkoxyl wherein the alkyl moiety of the loweralkylthio and loweralkoxyl comprises 1 to 6 carbon atoms.
The preferred esters used as protecting groups are those where R' is benzyl, p-nitrobenzyl, o-nitrobenzyl, t-butyl, bromo-t-butyl, t-butyl-dimethylsilyl, trimethylsilyl, trichloroethyl; or R' represents pharmaceutically acceptable ester moieties such as pivalyloxymethyl, allyl, methallyl, (2-methylthio)-ethyl, or 3-buten-1-yl.
The following compounds, presented in tabular form, further illustrate especially preferred embodiments of I.
The 1-carba-2-penem-3-carboxylic acids (I) form a wide variety of pharmacologically acceptable salts with inorganic and organic bases; these include, for example, metal salts derived from alkali metal or alkaline earth metal hydroxides, carbonates or bicarbonates and salts derived from primary, secondary or tertiary amines such as monoalkylamines, dialkylamines, trialkylamines, lower alkanolamines, di-loweralkanolamines, lower alkylenediamines, N,N-diaralkyl lower alkylenediamines, aralkylamines, amino substituted lower alkanols, N,N-di-lower alkylamino substituted lower alkanols, amino-, polyamino- and guanidino-substituted lower alkanoic acids and nitrogen containing heterocyclic amines. Representative examples include salts derived from sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium hydroxide, calcium carbonate, trimethylamine, triethylamine, piperidine, morpholine, quinine, lysine, protamine, arginine, procaine, ethanolamine, morphine, benzylamine, ethylenediamine, N,N'-dibenzylethylenediamine, diethanolamine, piperazine, dimethylaminoethanol, 2-amino-2-methyl-1-propanol, theophylline, N-methylglucamine and the like.
Salts of the amino group carried in certain species of I on side chains R.sup.1, R.sup.2 and R.sup.3 are also contemplated. Such pharmaceutically acceptable acid addition salts are derived from organic and inorganic acids such as HCl, HBr, citric, tartaric and the like.
The salts can be mono-salts such as the mono- sodium salt obtained by treating one equivalent of sodium hydroxide with one equivalent of the product (I), also mixed di-salts. Such salts may be obtained by treating one equivalent of a base having a divalent cation, such as calcium hydroxide, with one equivalent of the product (I). The salts of this invention are pharmacologically acceptable nontoxic derivatives which can be used as the active ingredient in suitable unit-dosage pharmaceutical forms. Also, they may be combined with other drugs to provide compositions having a broad spectrum of activity.
The novel 1-carba-2-penem-3-carboxylic acids are valuable antimicrobial substances which are active against various gram-positive and gram-negative pathogens. Thus, the free acid and especially the salts thereof such as amine and metal salts, particularly the alkali metal and alkaline earth metal salts, are useful bactericides and can be used for removing susceptible pathogens from dental and medical equipment, for separating microorganisms, and for therapeutic use in humans and animals. For this latter purpose pharmacologically acceptable salts with inorganic and organic bases such as those known in the art and used for the administration of penicillins and cephalosporins can be utilized. For example, salts such as alkali metal and alkaline earth metal salts, and primary, secondary and tertiary amine salts can be used for this purpose. These salts can be combined with pharmaceutically acceptable liquid and solid vehicles to form suitable dosage unit forms such as pills, tablets, capsules suppositories, syrups, elixirs and the like which can be prepared in accordance with procedures well known in this art.
The novel compounds are valuable antibiotics active against various gram-positive and gram-negative bacteria and, accordingly, find utility in human and veterinary medicine. The compounds of this invention can therefore be used as antibacterial drugs for treating infections caused by gram-positive or gram-negative bacteria, for example against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Bacillus subtilis, Salmonella typhosa, Pseudomonas and Bacterium proteus. The antibacterials of the invention may further be utilized as additives to animal feedingstuffs, for preserving foodstuffs and as disinfectants. For example, they may be employed in aqueous compositions in concentrations ranging from 0.1 to 100 parts of antibiotic per million parts of solution in order to destroy and inhibit the growth of harmful bacteria on medical and dental equipment and as bactericides in industrial applications, for example in waterbased paints and in the white water of paper mills to inhibit the growth of harmful bacteria.
The final products provided by this invention may be used alone or in combination as an active ingredient in any one of a variety of pharmaceutical preparations. These antibiotics and their corresponding salts may be employed in capsule form or as tablets, powders or liquid solutions or as suspensions or elixirs. They may be administered orally, intravenously or intramuscularly.
The compositions are preferably presented in a form suitable for absorption by the gastro-intestinal tract. Tablets and capsules for oral administration may be in unit dose presentation form, and may contain conventional excipients such as binding agents, for example, syrup, acacia, gelatin, sorbitol, tragacanth, or polyvinylpyrrolidone; fillers for example, lactose, sugar, maizestarch, calcium phosphate, sorbitol or glycine; lubricants, for example, magnesium stearate, talc, polyethylene glycol, silica; disintegrants, for example, potato starch or acceptable wetting agents such as sodium lauryl sulphate. The tablets may be coated according to methods well known in the art. Oral liquid preparations may be in the form of aqueous or oily suspension, solution, emulsions, syrups, elixirs, etc. or may be presented as a dry product, for reconstitution with water or other suitable vehicles before use. Such liquid preparations may contain conventional additives such as suspending agents, for example, sorbitol syrup, methyl cellulose, glucose/sugar syrup, gelatin, hydroxyethylcellulose, carboxymethyl cellulose, aluminum stearate gel or hydrogenated edible oils, for example almond oil, fractionated coconut oil, oily esters, propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoates or sorbic acid. Suppositories will contain conventional suppository bases, e.g., cocoa butter or other glyceride.
Compositions for injection may be presented in unit dose form in ampules, or in multidose containers with an added preservative. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient may be in powder form for reconstitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use.
The compositions may also be prepared in suitable forms for absorption through the mucous membranes of the nose and throat or bronchial tissues and may conveniently take the form of powder or liquid sprays or inhalants, lozenges, throat paints, etc. For medication of the eyes or ears, the preparations may be presented as individual capsules, in liquid or semi-solid form, or may be used as drops etc. Topical applications may be formulated in hydrophobic or hydrophilic bases as ointments, creams, lotions, paints, powders, etc.
Also, in addition to a carrier, the instant compositions may include other ingredients such as stabilizers, binders, antioxidants, preservatives, lubricators, suspending agents, viscosity agents or flavoring agents and the like. In addition, there may also be included in the composition other active ingredients to provide a broader spectrum of antibiotic activity.
For veterinary medicine the composition may, for example, be formulated as an intramammary preparation in either long acting or quick-release bases.
The dosage to be administered depends to a large extent upon the condition of the subject being treated and the weight of the host, the route and frequency of administration, the parenteral route being preferred for generalized infections and the oral route for intestinal infections. In general, a daily oral dosage consists of from about 15 to about 600 mg. of active ingredient per kg. of body weight of the subject in one or more applications per day. A preferred daily dosage for adult humans lies in the range of from about 80 to 120 mg. of active ingredient per kg. of body weight.
The instant compositions may be administered in several unit dosage forms as, for example, in solid or liquid orally ingestible dosage form. The compositions per unit dosage, whether liquid or solid may contain from 0.1% to 99% of active material, the preferred range being from about 10-60%. The composition will generally contain from 15 mg. to about 1500 mg. of the active ingredient; however, in general, it is preferable to employ a dosage amount in the range of from about 250 mg. to 1000 mg. In parenteral administration the unit dosage is usually the pure compound in a slightly acidified sterile water solution or in the form of a soluble powder intended for solution.
The following examples illustrate but do not limit the product or process aspects of the present invention.
EXAMPLE 1
Preparation of 1-carba-2-penem-carboxylic acid; and the benzyl ester and sodium salt thereof ##STR42##
Step A: 1-(Benzyloxycarbonylhydroxymethyl)-4-(2-acetoxyethyl)-2-azetidinone ##STR43##
Dibenzyl tartarate, 2.0 g, is dissolved in 8 ml tetrahydrofuran (THF) and placed under N.sub.2 ; periodic acid 1.7 g, dissolved in THF (80 ml) is added all at once and the reaction mixture is stirred vigorously for 30 minutes at 25.degree. C. The resulting solution is filtered; the filtrate is evaporated; the residue is taken up in benzene (50 ml); filtered again; and finally evaporated to give benzylglyoxalate mixed with its hydrate. The 4-(2-acetoxyethyl)-azetidinone, 1.0 g, is dissolved in benzene (80 ml) in a 3 neck flask fitted with a Dean-Stark water separator containing 2 g CaH.sub.2 to trap the water, and a dropping funnel. The solution is refluxed until the CaH.sub.2 shows no further reaction. The benzylglyoxalate and its hydrate from above is dissolved in benzene (80 ml) and added dropwise to the refluxing solution of the azetidinone over 1 hour; the reaction mixture is then refluxed another 3 hours. The reaction mixture is cooled and filtered. The filtrate is evaporated and the residue chromatographed on silica gel using 25% ethylacetate/benzene containing 1% methanol to give 1.85 g of product: 1-(benzyloxycarbonylhydroxymethyl)-4-(2-acetoxyethyl)-2-azetidinone.
i.r./.mu.: 2.8 (OH); 5.7 (broad, .beta.-lactam ester carbonyl). ##STR44##
Step B: 1-(Benzyloxycarbonylchloromethyl)-4-(2-acetoxyethyl)-2-azetidinone ##STR45##
1-(Benzyloxycarbonyl hydroxymethyl)-4-(2-acetoxyethyl)-2-azetidinone (1.8 g) is dissolved in 30 ml THF under N.sub.2 and cooled to -20.degree. C. Pyridine 0.45 ml is added and then thionylchloride (0.390 ml in 4 ml THF) is added dropwise over 2 minutes. The reaction mixture is stirred at -20.degree. C., for 5 minutes. The cooling bath is removed and the reaction mixture is stirred for another 25 minutes. The reaction mixture is diluted with 30 ml benzene and filtered. The filtrate is evaporated under reduced pressure at 5.degree. C. The residue is 1-(benzyloxycarbonylchloromethyl)-4-(2-acetoxyethyl)-2-azetidinone which is used directly in the next reaction.
Step C: 1-(Benzyloxycarbonylmethylenetriphenylphosphoranyl)-4-(2-acetoxyethyl)-2-a zetidinone ##STR46##
The 1-(benzyloxycarbonylchloromethyl)-4-(2-acetoxyethyl)-2-azetidinone (1.8 g) from Step B is dissolved in dimethylformamide (DMF) (20 ml) and treated with triphenylphosphine (1.47 g). The reaction mixture is stirred under N.sub.2 at 25.degree. C., for 1 hour. The DMF is removed under reduced pressure and the residue is taken up in CH.sub.2 Cl.sub.2 and washed with pH 7 phosphate buffer. The CH.sub.2 Cl.sub.2 solution is dried and evaporated to give the crude product. Chromatography on silica gel using ethylacetate as eluant gives 2.9 g 1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-4-(2-acetoxyethyl)-2-a zetidinone.
i.r. .mu. 5.7 (.beta.-lactam, acetoxy ester); 6.1 (benzyl ester) n.m.r..delta.: 1.95 ##STR47## 4.74 and 5.06 (C.sub.6 H.sub.5 CH.sub.2 O).
Step D: 1-(Benzyloxycarbonylmethyltriphenylphosphoranyl)-4-(2-hydroxyethyl)-2-azet idinone ##STR48##
The 1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-4-(2-acetoxyethyl)-2-a zetidinone (2.9 g) from Step C is dissolved in methanol (100 ml) and treated with 0.300 g of sodium methoxide. The reaction mixture is stirred under N.sub.2 at 25.degree. C., for 1 hour. Most of the methanol is removed under reduced pressure. The residue is taken up in 150 ml CH.sub.2 Cl.sub.2 and washed once with pH 7 buffer, then dried and evaporated. The residue is chromatographed on silica gel using 5% methanol in ethylacetate as eluant to give 2.4 g of 1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-4-(2-hydroxyethyl)-2-a zetidinone.
i.r. .mu.: 2.9 (OH); 5.72 (.beta.-lactam) 6.1 (ester carbonyl).
Step E: Benzyl-1-carba-2-penem-3-carboxylate ##STR49##
The 1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-4-(2-hydroxyethyl)-2-a zetidinone (0.546 g) from Step D is dissolved in 10 ml dimethylsulfoxide (DMSO) and 10 ml of acetic anhydride is added. The reaction mixture is stirred under N.sub.2 at 25.degree. C., for 3.5 hours. The acetic anhydride and DMSO are removed under reduced pressure at 25.degree. C., and the residue is purified by preparative thin layer chromatography on silica gel using 25% ethylacetate in benzene as eluant to give 0.081 g of benzyl-1-carba-2-penem-3-carboxylate.
U.V. .lambda..sub.max (H.sub.2 O/dioxane) 269, .epsilon.=5500.
M.S. M.sup.+ 243
i.r. .mu. 5.59 (.beta.-lactam), 5.78 (ester), 6.19 (c=c)
n.m.r..delta.: 7.3 (C.sub.6 H.sub.5): 6.36 t(C-2H); 5.2 S(C.sub.6 H.sub.5 CH.sub.2 O) 4.2 m(C-5H); 2.5 to 3.7 m(C-6H and C-1H).
Step F: Sodium 1-carba-2-penem-3-carboxylate ##STR50##
The Benzyl 1-carba-2-phenem-3-carboxylate (0.010 g) from Step E is dissolved in 1 ml dioxane, treated with 1 ml H.sub.2 O and 0.01 ml pH 7 0.5 molar phosphate buffer; 0.002 g of 10% Pd/C catalyst is added and the reaction mixture is reduced under H.sub.2 at 40 lbs for 7 minutes. The catalyst is filtered off and washed with water. The filtrate and washings are extracted with CH.sub.2 Cl.sub.2 and the aqueous phase is concentrated and freeze dried to give sodium 1-carba-2-penem-3-carboxylate.
U.V. .lambda..sub.max 262 nm.
EXAMPLE 1a
Preparation of Di-o-nitrobenzyltartarate
Tartaric acid (15.0 g, 0.1 mole) is dissolved in 40 ml. water and treated with lithium hydroxide (8.4 g, 0.2 mole). The resulting solution is evaporated to a small volume under reduced pressure and the residue is treated with p-dioxane. The resulting precipitate is filtered and dried under vacuum to give the di-lithium tartarate (17.7 g).
Di-lithium tartarate (9.46 g, 0.0585 mole) is suspended in 200 ml. DMF and treated with o-nitrobenzyl chloride (20 g, 0.117 mole) and sodium iodide (17.5 g, 0.117 mole). The mixture is stirred under N.sub.2 for 21/2 days at 65.degree. C.
The solvent is removed under vacuum and the resulting paste is treated with water and sodium thiosulfate (5 g). The resulting solid is filtered and dried to give di-o-nitrobenzyltartarate (17.0 g, 0.040 mole, 69%, m.p. 128.degree. C.).
n.m.r. (DMSO).delta.: 4.8 d (j=7, H-C-OH), 5.23d (j=7, H-C-OH), 5.7 S (O-CH.sub.2 -C.sub.6 H.sub.4 -NO.sub.2); 7.73 & 8.2 m (aromatic H).
Similar treatment of the di-lithium salt with R'X (where X=Cl, Br or I) such as p-nitrobenzylbromide, benzylbromide, pivalyoxymethyl chloride gives the corresponding di-ester of tartaric acid such as di-p-nitrobenzyl tartarate, di-benzyl tartarate, dipivaloyloxymethyl tartarate. These can be used as alternates to di-benzyl tartarate in Example 1.
EXAMPLE 2
Preparation of trans-3-isopropyl-4-(2-acetoxyethyl)-2-azetidinone ##STR51##
Step A: 8-oxo-2,2-dimethyl-7.alpha.-isopropyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR52##
THF, 20 ml is placed under N.sub.2, treated with 1.54 ml diisopropylamine and cooled to -78.degree. C. A solution of n-butyl lithium 1.97 M in hexane 5.6 ml is added dropwise over 5 min. The reaction mixture is stirred at -78.degree. C. for 10 min and then treated with 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane 1.55 g in 15 ml THF added dropwise over 5 min. After another 10 min hexamethylphosphoramide 1.97 ml is added. The mixture is stirred another 10 min. then treated with 2 ml of isopropyl iodide. The reaction mixture is stirred at -78.degree. C. for 15 min and allowed to warm to 25.degree. C. and stirred for 15 min. The reaction mixture is diluted with EtOAc, washed once with pH 7 phosphate buffer then dried and evaporated. The residue is chromatographed on silica gel using 25% EtOAc/C.sub.6 H.sub.6 as eluant to give 8-oxo-2,2-dimethyl-7.alpha.-isopropyl-3-oxa-1-azabicyclo[4.2.0]octane. .mu. i.r.: 5.7 (.beta.-lactam).
n.m.r..delta.: 0.96d, 1.06d ##STR53## 1.4S, 1.76S (gem dimethyl); 1.9m (C-5H); 2.59d of d (C-7H); 3.33m (C-6H); 3.82 d of d (C-4H).
Step B: Trans-3-isopropyl-4-(2-hydroxyethyl)-2-azetidinone ##STR54##
8-oxo-2,2-dimethyl-7.alpha.-isopropyl-3-oxa-1-azabicyclo[4.2.0]octane 1.0 g is dissolved in 8 ml of acetic acid and 2 ml H.sub.2 O is added. The mixture is heated at 65.degree. C. for 1.25 hrs. The acetic acid and H.sub.2 O are removed under reduced pressure and the residue is taken up in C.sub.6 H.sub.6 and evaporated to give 3-isopropyl-4-(2-hydroxyethyl)-azetidinone.
Step C: Trans-3-isopropyl-4-(2-acetoxyethyl)-2-azetidinone ##STR55##
Trans-3-isopropyl-4-(2-hydroxyethyl)-2-azetidinone from Step B, is dissolved in 10 ml. CH.sub.2 Cl.sub.2 and cooled to 0.degree. C. Pyridine 0.75 ml is added and then 0.392 ml of acetyl chloride is added dropwise. The mixture is stirred at 0.degree. for 15 min and then at 25.degree. C. for another 15 minutes. The reaction mixture is evaporated to dryness. The residue is chromatographed on silica gel using 50% EtOAc/C.sub.6 H.sub.6 as eluant to give 0.652 g 3-isopropyl-4-(2-acetoxyethyl)-azetidinone.
i.r. .mu.: 5.7 (broad .beta.-lactam-ester carbonyl) 3.5 NH
n.m.r..delta.: 1.0d, 1.1d ##STR56## 2.63d (C-3H); 3.43 d of t (C-4H) 4.13t (CH.sub.2 -OAc), 7.03 (NH).
EXAMPLE 3
Preparation of Trans-3-benzyl-4-(2-acetoxyethyl)-2-azetidinone ##STR57##
Step A: 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR58##
Following the procedure described for the preparation of 8-oxo-3-oxa-2,2-dimethyl-7.alpha.-isopropyl-1-azabicyclo[4.2.0]octane from 8-oxo-3-oxa-2,2-dimethyl-1-azabicyclo[4.2.0]octane and using benzyl bromide instead of isopropyl iodide there is obtained 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane.
i.r..mu.: 5.73 (.beta.-lactam)
n.m.r..delta.: 1.33S, 1.75S (gem dimethyl); 1.74m (C-5 H) 3.0 d of d (C.sub.6 H.sub.5 -CH.sub.2); 3.73 d of d (C-2 H) 7.25S (C.sub.6 H.sub.5).
Step B: Trans-3-benzyl-4-(2-hydroxyethyl)-2-azetidinone ##STR59##
8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]-octane (1.0 g) is dissolved in 8 ml acetic acid and 2 ml H.sub.2 O and heated at 65.degree. C. for 1.25 hrs. The acetic acid and H.sub.2 O are removed under reduced pressure and the residue is taken up in C.sub.6 H.sub.6 and evaporated to give trans-3-benzyl-4-(2-hydroxyethyl)-2-azetidinone.
Step C: Trans-3-benzyl-4-(2-acetoxyethyl)-2-azetidinone ##STR60##
Trans-3-benzyl-4-(2-hydroxyethyl)-2-azetidinone is acetylated as described for the acetylation of trans-3-isopropyl-4-(2-hydroxyethyl)-2-azetidinone to give trans-3-benzyl-4-(2-acetoxyethyl)-2-azetidinone.
EXAMPLE 4
Preparation of Sodium 6.alpha.-(1-hydroxyethyl)-1-carba-2-penem-3-carboxylate ##STR61##
Step A: Benzyl 6.alpha.-(1-methylthiomethyleneoxy)ethyl-2-penem-3-carboxylate ##STR62##
Following exactly the procedures described for conversion of trans-3-isopropyl-1-carba-4-(2-acetoxyethyl)-2-azetidinone to benzyl-6.alpha.-isopropyl-1-carba-2-penem-3-carboxylate, there is obtained benzyl-6.alpha.-(1-methylthiomethyleneoxy)ethyl-1-carba-2-penem-3-carboxyl ate from trans-3-(1-methyleneoxy)ethyl-4-(2-acetoxyethyl)-2-azetidinone.
i.r. .mu. 5.6 (.beta.-lactam); 5.79 (ester); 6.2 (C.dbd.C)
n.m.r.: 1.33d (CH.sub.3 -CH); 2.17s (CH.sub.3 S); 2.85m (C-1 H); 3.4m (C-6 H); 4.2m (C-5H); 5.25s (C.sub.6 H.sub.5 CH.sub.2) 6.45t (C-2 H); 7.35s (C.sub.6 H.sub.5)
Step B: Benzyl 6.alpha.-(1-hydroxyethyl)-1-carba-2-penem-3-carboxylate ##STR63##
Benzyl 6.alpha.-(1-methylthiomethyleneoxy)-ethyl-2-penem-3-carboxylate (0.100 g) is dissolved in 4 ml acetonitrile 1 ml water. Mercuric chloride 1.5 eq is added and the mixture is stirred at 25.degree. C. for 4 hrs. The reaction mixture is filtered through celite and washed with EtOAc. The filtrate and washings are washed with a solution of ammonium chloride then dried and evaporated. The residue is purified by preparative t.l.c. (50% EtOAc/C.sub.6 H.sub.6, silica gel) to give Benzyl-6.alpha.-(1-hydroxyethyl)-2-penem-3-carboxylate.
Step C: Sodium 6.alpha.-(1-hydroxyethyl)-1-carba-2-penem-3-carboxylate ##STR64##
Benzyl 6.alpha.-(1-hydroxyethyl)-2-penem-3-carboxylate is hydrogenated using the procedure described in Step F, Example 1 to give sodium 6.alpha.-(1-hydroxyethyl)-2-penem-3-carboxylate.
EXAMPLE 5
Benzyl-6.alpha.-benzyl-2-penem-3-carboxylate ##STR65##
Following exactly the procedures described for conversion of trans-3-isopropyl-4-(2-acetoxyethyl)-2-azetidinone to benzyl-6.alpha.-isopropyl-2-penem-3-carboxylate one obtains benzyl-6.alpha.-benzyl-2-penem-3-carboxylate from trans-3-benzyl-4-(2-acetoxyethyl)-2-azetidinone.
i.r..mu.: 5.59 (.beta.-lactam); 5.79 (ester); 6.19 (C.dbd.C)
n.m.r..delta.: 2.73m(C-1H); 3.2 d of d (C.sub.6 H.sub.5 -CH.sub.2 C); 3.5m(C-6H); 4.05 d of t (C-5H); 5.26s(C.sub.6 H.sub.5 CH.sub.2 -O) 6.4t(C-2H); 7.26s and 7.36s (C.sub.6 H.sub.5)
Sodium-6.alpha.-benzyl-2-penem-3-carboxylate
Benzyl-6.alpha.-benzyl-2-penem-3-carboxylate is hydrogenated using the procedure described in Step F Example 1 to give sodium 6.alpha.-benzyl-2-penem-3-carboxylate
EXAMPLE 6
Preparation of trans-3-(1-methylthiomethyleneoxy)-ethyl-4-(2-acetoxyethyl)-2-azetidinone ##STR66##
Step A: 8-oxo-2,2-dimethyl-7.alpha.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]-oct ane ##STR67##
The lithium enolate of 8-oxo-3-oxa-2,2-dimethyl-1-azabicyclo[4.2.0]-octane is prepared as described in the preparation of 8-oxo-3-oxa-2,2-dimethyl-7.alpha.-isopropyl-1-azabicyclo[4.2.0]-octane. The enolate at -78.degree. C. is treated with excess acetaldehyde at 78.degree. C. and the reaction mixture is allowed to warm to 25.degree. C. and stirred for 15 minutes. Work up as described before gives 8-oxo-3-oxa-2,2-dimethyl-7.alpha.-(1-hydroxyethyl)-1-azabicyclo[4.2.0]-oct ane.
i.r..mu.: 2.9 (OH); 5.73 (broad .beta.-lactam)
n.m.r..delta.: 1.29 d (CH.sub.3 -CH-); 1.41-1.75 s (gem dimethyl); 1.85 m (C-5 H); 2.85 m (C-7 H); 3.85 d of d (C-4 H); 4.1 m (CH.sub.3 -CH-O) 3.6 m (C-6 H)
Step B: 8-oxo-2,2-dimethyl-7.alpha.-(1-methylthiomethyleneoxy)-ethyl-3-oxa-1-azabi cyclo[4.2.0]-octane ##STR68##
8-oxo-3-oxa-2,2-dimethyl-7.alpha.-(1-hydroxyethyl)-1-azabicyclo[4.2.0]-octa ne (1.04 g) is dissolved in 5 ml DMF under N.sub.2 and treated with sodium hydride (0.330 g 57% in mineral oil, 1.5 eq). The reaction mixture is stirred for 1 hour. Chloromethylmethylsulfide (0.964 ml, 2-eq) is added and the reaction mixture is stirred another 2 hours. Acetic acid (0.5 ml) is added to destroy excess sodium hydride and the reaction mixture is evaporated to dryness under reduced pressure below 40.degree. C. The residue is taken up in CH.sub.2 Cl.sub.2, washed with water, dried and evaporated. The residue is chromatographed to give 8-oxo-2,2-dimethyl-7.alpha.-(1-methylthiomethyleneoxy)-ethyl-3-oxa-1-azabi cyclo[4.2.0]-octane (0.275 g) and recovered starting material (0.435 g).
i.r..mu.: 5.7 (.beta.-lactam)
n.m.r..delta.: 1.25 d (CH.sub.3 -CH-); 1.42 and 1.73 s(gem dimethyl); 2.16S (CH.sub.3 -S); 1.85 m(C-5 H); 2.85 m (C-7 H); 3.83 d of d (C-4 H) 4.1 m (CH.sub.2 -CH-); 4.81 d of d (O-CH.sub.2 -S); 3.6 m (C-6 H).
Step C: Trans-3-(1-methylthiomethyleneoxy)ethyl-4-(2-hydroxyethyl)-2-azetidinone ##STR69##
8-oxo-3-oxa-2,2-dimethyl-7.alpha.-(1-methylthiomethyleneoxy)-ethyl-1-azabic yclo[4.2.0]-octane (0.460 g) is dissolved in 8 ml acetic acid and 2 ml H.sub.2 O and allowed to stand at 25.degree. C. for 48 hrs. The acetic acid and H.sub.2 O are removed under reduced pressure. The residue is purified by preparative t.l.c. to give trans-3-(1-methylthiomethyleneoxy)ethyl-4-(2-hydroxyethyl)-2-azetidinone.
Step D: Trans-3-(1-methylthiomethyleneoxy)ethyl-4-(2-acetoxyethyl)-2-azetidinone ##STR70##
Trans-3-(1-methylthiomethyleneoxy)ethyl-4-(2-hydroxyethyl)-2-azetidinone is acetylated as described in the preparation of trans-3-(isopropyl)-4-(2-acetoxyethyl)-2-azetidinone to give trans-3-(1-(methylthiomethyleneoxy)ethyl-4-(2-acetoxyethyl)-2-azetidinone.
i.r..delta. 3.0 NH; 5.7 (broad, .beta.-lactam--ester carboxyls). ##STR71##
EXAMPLE 7
Preparation of Sodium-6.alpha.-isopropyl-1-carba-2-penem carboxylate ##STR72##
Step A: Trans-1-(benzyloxycarbonylhydroxymethyl)-3-isopropyl-4-(2-acetoxyethyl)-2- azetidinone ##STR73##
Benzyl glyoxalate is prepared from 0.390 g of dibenzyl tartarate as described in Example 1 Step A, dissolved in 30 ml C.sub.6 H.sub.6 and refluxed using a Dean-Stark water separator according 1 g of CaH.sub.2 for 2 hours. Trans-3-isopropyl-4-(2-acetoxyethyl)-2-azetidinone (0.214 g) is added and the mixture is refluxed 8 hrs, cooled, filtered and evaporated. The residue is purified by preparative t.l.c. to trans-1-(benzyloxycarbonylhydroxymethyl)-3-isopropyl-4-(2-acetoxyethyl)-2- azetidinone (0.395 g). i.r..mu.: 2.9 (OH); 5.7 (broad .beta.-lactam--ester carbonyls).
Step B: Trans-1-(benzyloxycarbonylchloromethyl)-3-isopropyl-4-(2-acetoxymethyl)-2- azetidinone ##STR74##
Trans-1-benzyloxycarbonylhydroxymethyl)-3-isopropyl-4-(2-acetoxymethyl)-2-a zetidinone (0.395 g) is treated with pyridine (0.094 ml) and SOCl.sub.2 (0.084 ml) following the procedure of Example 1, Step B to give the trans-1-(benzyloxycarbonylchloromethyl)-3-isopropyl-4-(2-acetoxyethyl)-2-a zetidinone which is used directly in the next reaction.
Step C: Trans-1-(benzyloxycarbonylmethylenetriphenylphosphorany)-3-isopropyl-4-(2- acetoxyethyl)-2-azetidinone ##STR75##
Trans-1-(benzyloxycarbonylchloromethyl)-3-isopropyl-4-(2-acetoxyethyl)-2-az etidinone from above is treated with 0.296 g of triphenylphosphine following the procedure of Example 1 Step E. to give trans-1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-3-isopropyl-4-(2 -acetoxyethyl)-2-azetidinone.
n.m.r..delta.: 0.9 m ##STR76## 1.9 m (CH.sub.2 -CH-OAc), 1.98 s ##STR77## 2.63 d of d (C-3 H); 3.46 m (C-4 H); 4.03 g (CH.sub.2 -O-Ac) 5.13 s (C.sub.6 H.sub.5 CH.sub.2) 7.26 m (C.sub.6 H.sub.5)
Step D: Trans-1-(Benzyloxycarbonylmethylenetriphenylphosphoranyl)-3-isopropyl-4-(2 -hydroxyethyl)-2-azetidinone ##STR78##
Trans-1-(benzyloxycarbonylmethylenetriphosphoranyl)-3-isopropyl-4-(2-acetox yethyl)-2-azetidinone from the previous experiment is hydrolyzed using the procedure of Example 1, Step D to give trans-1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-3-isopropyl-4-(2 -hydroxyethyl)-2-azetidinone (0.276 g).
Step E: Benzyl-6.alpha.-isopropyl-2-penem-3-carboxylate ##STR79##
The trans-1-(benzyloxycarbonylmethylenetriphenylphosphoranyl)-3-isopropyl-4-(2 -hydroxyethyl)-2-azetidinone 0.100 g is treated with DMSO and acetic anhydride following the procedure of Step E, Example 1 to give 0.026 g of benzyl-6.alpha.-isopropyl-2-penem-3-carboxylate.
i.r..mu.: 5.6 (.beta.-lactam); 5.79 (ester); 6.2 (C.dbd.C)
n.m.r..delta.: 0.96d-1.1d ##STR80## 2.9 m (C-1 H, & C-6 H); 4.0 d of t (C-5 H); 5.26 s (CH.sub.2 -C.sub.6 H.sub.5); 6.43 t (C-2 H); 7.33 s (C.sub.6 H.sub.5)
Step F: Sodium-6.alpha.-isopropyl-2-penem-3-carboxylate ##STR81##
Benzyl 6.alpha.-isopropyl-2-penem-3-carboxylate is hydrogenated using the procedure described in Step F, Example 1 to give Sodium-6.alpha.-isopropyl-2-penem-3-carboxylate.
EXAMPLE 8
Preparation of 4-(2-Acetoxyethyl)-Azetidinone, 3-(1-hydroxyethyl)-4-(2-acetoxyethyl)-Azetidinone, and 3-(1-hydroxyethyl)-4-(2-hydroxyethyl)-Azetidinone
Step A
Preparation of 4-(2-acetoxyvinyl)azetidine-2-one ##STR82##
A solution of 1.0 ml distilled chlorosulfonylisocyanate (1.65 g; 11.7 mmoles) in 2.5 ml anhydrous diethyl ether is cooled under N.sub.2 in a -20.degree. C. bath.
A solution of 2.5 g 1-acetoxybutadiene (22 mmoles) in 2.5 ml anhydrous ether is similarly cooled under N.sub.2 in a -20.degree. C. bath.
The chlorosulfonylisocyanate solution is added dropwise to the acetylbutadiene solution by means of a Teflon tube immersed in the CSI solution and pressurized with N.sub.2. The addition takes 10 minutes. Little or no color is seen and the reaction is stirred at <20.degree. C. for 0.5 hour. The solution is clear and has a light yellow color.
A solution of 2 g sodium sulfite and 5 g K.sub.2 HPO.sub.4 in 20 ml H.sub.2 O is prepared during the above 0.5 hour reaction time and is cooled in an ice bath; 20 ml of ether is added and the mixture is vigorously stirred in an ice bath. At the end of the 30 minute reaction time, the reaction mixture is transferred, again using N.sub.2 pressure and the Teflon tube, from the reaction flask which is maintained in the -20.degree. C. bath, to the vigorously stirred hydrolysis mixture. Rapid dropwise addition is completed in 5 minutes. The hydrolysis is allowed to continue for 5 additional minutes. The hydrolysis mix has a pH of 6-8, preferably pH 8.
The phases are separated, leaving a yellowish-orange gum with the aqueous phase. The ether phase is dried directly with MgSO.sub.4. The aqueous/gum phase is extracted three more times with 50 ml portions of ether, each being added to the initial ether/MgSO.sub.4.
The dried extracts are filtered and concentrated under a N.sub.2 stream to 5 ml; a portion of the product is crystalline at this stage.
A column of 10 g Baker silica gel, packed in ether is prepared, and the ether concentrate is applied to the top and run in. The flask/solids are rinsed three times with 2 ml ether, each being pipetted off and run into the column. Elution is then begun with ether. The first 25 ml is primarily void volume. The next five 10 ml fractions are collected followed by three 50 ml fractions, and all are reduced in volume under a N.sub.2 stream. The product crystallizes from fractions 4-6, with traces in 3 and 7. Fractions 1-3 contain a yellowish sharp-smelling material which resinifies on standing. Yield: 100 mg as a mixture of the cis and trans isomers.
Step B
Preparation of 4-(2-Acetoxyethyl)-2-Azetidinone ##STR83##
A solution of 4-(2-acetoxyvinyl)-2-azetidinone (10.0 g, 0.065 mole) in 200 ml ethyl acetate containing 100 mg of 10% Pd/C is hydrogenated on a Parr shaker at 25.degree. C. under 40 psi hydrogen for 15 minutes. The mixture is filtered through a bed of Supercel and washed with additional ethyl acetate. The combined filtrate is evaporated in vacuo to give 4-(2-acetoxyethyl)-2-azetidinone (10.0 g) as a crystalline solid. Recrystallization from ether affords white crystals: M.P. 44.degree.-7.degree.; ir (CHCl.sub.3).mu. 5.66, 5.74; nmr (CDCl.sub.3).tau.3.44 (broad s, 1, NH), 5.82 (m, 2, CH.sub.2 OCOCH.sub.3), 6.29 (m, 1, C-4H), 6.87 (1/2 AB pattern further split in four by C-4H and NH, 1, J.sub.gem =12.8 Hz, J=4.5 H J.sub.NH =1.9 Hz, 7.38 (1/2 AB pattern further split in four by C-4H and NH, 1, J.sub.gem =12.8 Hz, J=2.3 Hz, J.sub.NH =1.0 Hz), 7.93 and 8.02 (s on m, total 5, OCOCH.sub.3 and CH.sub.2 CH.sub.2 OCOCH.sub.3, respectively).
Step C
Preparation of 4-(2-Hydroxyethyl)-2-Azetidinone ##STR84##
Under nitrogen at 0.degree., a solution of 4-(2-acetoxyethyl)-2-azetidinone (2.24 g, 0.014 mole) in 25 ml anhydrous methanol is treated with a solution of sodium methoxide (77 mg, 1.4 mmoles) in 5 ml anhydrous methanol. After stirring for 1 hour, the solution is neutralized with glacial acetic acid. Removal of the methanol in vacuo gives crude 4-(2-hydroxyethyl)-2-azetidinone as an oil. The product is purified by chromatography on silica gel eluting with 10% MeOH/CHCl.sub.3 to give 1.55 g of the alcohol: m.p. 50.degree.; ir (CHCl.sub.3) .mu. 5.67; nmr (CDCl.sub.3).tau.3.20 (broad s, 1, NH), 6.24 and 6.28 (m on t, total 3, C-4H and CH.sub.2 OH respectively), 6.90 (broad s on 1/2 AB pattern further split in four by C-4H and NH, total 2, OH and C-3H respectively, J.sub.gem =13.0 Hz, J.sub.vic =4.2 Hz, J.sub.NH =1.6 Hz), 7.42 (1/2 AB pattern further split in four by C-4H and NH, 1, C-3H, J.sub.gem =13.0 Hz, J.sub.vic =2.2 Hz, J.sub.NH =1.1 Hz), 8.16 (m, 2, CH.sub.2 CH.sub.2 OH).
Step D
Preparation of 8-Oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR85##
A solution of 4-(2-hydroxyethyl)-2-azetidinone (1.87 g, 0.016 mole) and 2,2-dimethoxypropane (1.69 g, 0.016 mole) in 25 ml anhydrous methylene chloride is treated with boron trifluoride etherate (0.201 ml, 0.002 mole) at 25.degree. C. The resulting solution is stirred for ten minutes. Removal of the solvent under reduced pressure gives an oil (2.5 g). Chromatography of the crude product on silica gel using 2:1 ethyl acetate/benzene as eluting solvent gives 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]-octane (1.59 g) as a crystalline solid. Recrystallization from ether/hexane gives product of m.p. 60.degree.-1.degree..
ir (CHCl.sub.3).mu.: 5.73 (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 6.02-6.28, m, 2H, C-4 methylene, 6.22-6.62, m, 1H, C-6 methine, 6.90, dd, 1H, J.sub.7,7 =14 Hz, J.sub.6,7 =4.5 Hz, C-7 proton cis to C-6H, 7.47, dd, 1H, J.sub.7,7 =14 Hz, J.sub.6,7 =2 Hz C-7 proton trans to C-6H 7.82-8.68, m, 2H, C-5 methylene
Step E
Preparation of 8-oxo-2,2-dimethyl-7.alpha. and .beta.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octane ##STR86##
To a solution of 1.1 equivalents of freshly prepared lithium diisopropylamide in anhydrous tetrahydrofuran under a nitrogen atmosphere at -78.degree. is added a solution of 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]-octane in anhydrous tetrahydrofuran which has been cooled to -78.degree. C. After two minutes, the resulting lithium enolate is treated with excess acetaldehyde. The solution is stirred for 30 minutes at -78.degree. and then poured into water. The aqueous phase is saturated with sodium chloride and extracted with ethyl acetate. The combined ethyl acetate solutions are dried over magnesium sulfate and filtered. The filtrate is evaporated under reduced pressure to give the crude product. Purification by chromatography on silica gel using ethyl acetate/benzene gives 8-oxo-2,2-dimethyl-7.alpha. and .beta.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octane. Data for 8-oxo-2,2-dimethyl-7.beta.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octan e:
ir (CH.sub.2 Cl.sub.2).mu.: 5.72.mu. (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 5.53-6.43, m, 4H, C-4 methylene+C-6 methine+C-9 methine 6.90, dd on broad s, 2H, J.sub.7,9 =9 Hz J.sub.6,7 =5.5 Hz, C-7 methine+OH 7.70-8.83, m, 2H, C-5 methylene
8.78, d, 3H, J.sub.9,10 =6.5 Hz, C-10 methyl
Data for 8-oxo-2,2-dimethyl-7.alpha.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octa ne:
ir (CHCl.sub.3).mu.: 2.9 broad O-H 5.73 .beta.-lactam
nmr (acetone-d.sub.6).tau.: 4.23-3.33, m, C-9 methine+C-4 methylene+C-6 methine 3.33, broad s, OH
1.93-1.63, m, C-5 methylene
1.23, d, J=6.5 Hz, C-10 methyl
Step F
Preparation of 8-Oxo-2,2-dimethyl-7.alpha.-(1-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-az abicyclo[4.2.0]octane ##STR87##
Under anhydrous conditions at 0.degree. C. a solution of 8-oxo-2,2-dimethyl-7.alpha.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octa ne (60 mg, 0.302 mmole) in 0.6 ml ether is treated with powdered potassium hydroxide (19 mg, 0.332 mmole). After a period of 15 minutes, p-nitrobenzyl chloroformate (65 mg, 0.302 mmole) is added to the reaction mixture. Stirring is continued at 25.degree. C. for an additional 15 hours. The mixture is partitioned between 1 M pH 7 phosphate buffer and more ether. The ether phase is washed with water and brine, dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives 67 mg of a colorless oil. Purification by preparative thick-layer chromatography on silica gel developing with 1:9 ethyl acetate/benzene gives 8-oxo-2,2-dimethyl-7.alpha.-(1-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-az abicyclo[4.2.0]octane (40 mg) as a mixture of diastereomers.
ir (CH.sub.2 Cl.sub.2).mu.: 5.68 (.beta.-lactam and carbonate), 6.19 and 6.54 (nitro)
nmr(CDCl.sub.3): 1.67, d, 2H, ArH 2.37, d, 2H, ArH 4.67, s, 2H, ArCH.sub.2 4.67-5.22, m, CH.sub.3 CH 5.98-6.25, m, 2H, C-4 methylene 6.25-6.62, m, 1H, C-6 methine 6.75-7.12, m, 1H, C-7 methine 7.75-8.83, m, 2H, C-5 methylene 8.22, s, 3H, C-2 methyl 8.50-8.58, m, 5H, C-2 methyl+CH.sub.3 CH
The 7.beta.-diastereoisomers or the 7.alpha. and .beta.-mixture are obtained in an analogous manner.
Step G
Preparation of Cis and Trans-3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-(2-hydroxyethyl)-2-azetidino ne ##STR88##
8-Oxo-3-oxa-2,2-dimethyl-7.alpha.-(1-p-nitrobenzylcarbonyldioxyethyl)-1-aza bicyclo[4.2.0]octane (1.0 g) is dissolved in 8 ml acetic acid and 2 ml water and heated at 65.degree. C. for 1.25 hours. The acetic acid and water are removed under reduced pressure and the residue is taken up in benzene and evaporated to give trans-3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-(2-hydroxyethyl)-2-azetidino ne as a mixture of diastereoisomers.
ir (CH.sub.2 Cl.sub.2).mu.: 5.67 (.beta.-lactam), 5.72 shoulder, 6.20 and 6.57 (nitro)
nmr (CDCl.sub.3): 1.73, d, 2H, J=8.5 Hz, ArH 2.43, d, 2H, J=8.5 Hz, ArH 3.63, broad s, 1H, NH 4.37-5.13, m, 1H, CH.sub.3 CH 4.72, s, 2H, ArCH.sub.2 6.07-6.53, m, 1H, C-4 methine 6.23, t, 2H, J=5.5 Hz, CH.sub.2 OH 6.73-6.93, m, 1H, C-3 methine 7.63-8.97, m, 3H, CH.sub.2 CH.sub.2 OH 8.53, d, J=6.5 Hz, CH.sub.3 CH
The cis diastereoisomers or the cis-trans mixture are obtained in an analogous manner.
Hydrogenation of 3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-(2-hydroxyethyl)-2-azetidinone according to the procedure of Example 1 Step F provides 3-(1-hydroxyethyl)-4-(2-hydroxyethyl)-2-azetidinone, which upon acetylation according to the procedure of Example 2, Step C provides 3-(1-hydroxyethyl)-4-(2-acetoxyethyl)-2-azetidinone; or acetylation by the procedure of Example 2, Step C provides 3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-(2-acetoxyethyl)-2-azetidinone.
Steps D', E', F' and G' as alternative to Steps D, E, F, and G for the preparation of 3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-(2-hydroxyethyl)azetidinone ##STR89##
Step D'
Preparation of 1-(2-Tetrahydropyranyl)-4-[2-(2-tetrahydropyranyl)oxyethyl]-2-azetidinone ##STR90##
Under nitrogen and at 25.degree. C. a solution of 4-(2-hydroxyethyl)-2-azetidinone (62 mg, 0.539 mmole) in 0.5 ml of anhydrous p-dioxane is treated with 2,3-dihydropyran (0.98 ml, 1.08 mmoles) and p-toluenesulfonic acid monohydrate (19 mg, 0.10 mmole). The resulting solution is stirred for a period of 60 minutes and then partitioned between 10 ml of 0.5 M pH 7 phosphate buffer and 10 ml of ethyl acetate. The aqueous phase is extracted a second time with ethyl acetate. The combined ethyl acetate solutions are washed with brine, dried over magnesium sulfate and filtered. The filtrate is evaporated under reduced pressure to give 216 mg of crude product. Purification by preparative thick-layer chromatography developing with ethyl acetate gives 80 mg of1-(2-tetrahydropyranyl)-4-[2-(2-tetrahydropyranyl)oxyethyl]-2-azetidinon e as an oil.
nmr (CDCl.sub.3).tau.: 5.13-5.60, m, OCH 5.83-6.85, m, C-4H+OCH.sub.2 ##STR91## 7.62-8.95, m, CHCH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 +CHCH.sub.2 CH.sub.2 O
Step E'
Preparation of Cis and Trans-1-(2-tetrahydropyranyl)-3-(1-hydroxyethyl)-4-[2-(2-tetrahydropyranyl )oxyethyl]-2-azetidinone ##STR92##
Following the procedure described for the preparation of 8-oxo-2,2-dimethyl-7.alpha. and .beta.-(1-hydroxyethyl)-3-oxa-1-azabicyclo [4.2.0] octane from 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo [4.2.0] octane and using 1-(2-tetrahydropyranyl)-4-[2-(2-tetrahydropyranyl)oxyethyl]-2-azetidinone one obtains a diastereomeric mixture of both cis and trans-1-(2-tetrahydropyranyl)-3-(1-hydroxyethyl)-4-[2-(2-tetrahydropyranyl )-oxyethyl]-2-azetidinone.
Step F'
Preparation of Cis and Trans-1-(2-tetrahydropyranyl)-3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-[2-( 2-tetrahydropyranyl)oxyethyl]-2-azetidinone ##STR93##
Following the procedure described for the preparation of 8-oxo-2,2-dimethyl-7.alpha.-(1-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-az abicyclo[4.2.0]octane from 8-oxo-2,2-dimethyl-7.alpha.-(1-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octa ne and using trans-1-(2-tetrahydropyranyl)-3-(1-hydroxyethyl)-4-[2-(2-tetrahydropyranyl )oxyethyl]-2-azetidinone there is obtained trans-1-(2-tetrahydropyranyl)-3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-[2-( 2-tetrahydropyranyl)oxyethyl]-2-azetidinone. The cis diastereoisomers are obtained in an analogous manner.
Step G'
Preparation of Cis and Trans-3-(1-p-nitrobenzylcarbonyl-dioxyethyl)-4-(2-hydroxyethyl)-2-azetidin one ##STR94##
A solution of trans-1-(2-tetrahydropyranyl)-3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-[2-( 2-tetrahydropyranyl)oxyethyl]-2-azetidinone in methanol at 25.degree. C. is treated with 0.1 molar equivalent of p-toluenesulfonic acid monohydrate. The solution is stirred for a period of 2 hours and then neutralized with 1 M pH7 phosphate buffer. The product is extracted into ethyl acetate. The ethyl acetate solution is washed with brine, dried over magnesium sulfate and filtered. The filtrate is evaporated under reduced pressure to give trans-3-(1-p-nitrobenzylcarbonyldioxyethyl)-4-(2-hydroxyethyl)-2-azetidino ne. The cis diastereoisomers are obtained in an analogous manner.
EXAMPLE 9
Preparation of 1-(t-butyldimethylsilyl)-4-(2-acetoxyethyl)-2-Azetidinone ##STR95##
A solution of 4-(2'-acetoxyethyl)-2-azetidinone (50.2 g, 0.32 mole) and t-butyldimethylchlorosilane (50.6 g, 0.335 mole) in 250 ml anhydrous N,N-dimethylformamide is treated at 0.degree. with triethylamine (35.6 g, 0.353 mole). A white precipitate appears immediately. The mixture is stirred for a period of five minutes. It is then partitioned between 1600 ml benzene and 600 ml water. The organic phase is washed an additional four times with water and finally with brine. The benzene solution is then dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives 84.0 g of 1-(t-butyldimethylsilyl)-4-(2'-acetoxyethyl)-2-azetidinone. Recrystallization from pentane gives 68.9 g of product with m.p. 35.degree..
nmr (CDCl.sub.3).tau.: 5.90, t, J=6 Hz, CH.sub.2 OCOCH.sub.3 6.17-6.60, m, C-4 methine 6.80, dd, J=14.5 Hz and 5 Hz, C-3 proton cis to C-4 methine 7.33, dd, J=14.5 Hz and 3 Hz, C-3 proton trans to C-4 methine 7.53-8.50, m, CH.sub.2 CH.sub.2 OCOCH.sub.3 7.97, s, OCOCH.sub.3 9.03, s, SiC(CH.sub.3).sub.3 9.75, s, Si(CH.sub.3).sub.2
EXAMPLE 10
1-(t-butyldimethylsilyl)-4-(2-hydroxyethyl)-2-azetidinone ##STR96##
1-(t-butyldimethylsilyl)-4-(2-acetoxyethyl)-2-azetidinone (1.94 g, 7.15 mmol) is dissolved in anhydrous methanol (20 ml) cooled to 0.degree. and a solution of NaOMe (0.36 mmol) in MeOH (0.5 ml) is added to the mixture stirred at 0.degree. for 2 hours. HOAC (0.1 ml) is added the mixture is evaporated under vacuum and the residue is taken up in CH.sub.2 Cl.sub.2 ; washed with water, 5% NaHCO.sub.3, dried and evaporated to a pale yellow oil. This is chromatographed on silica gel using EtOAc as eluant, to give 1-(t-butyldimethylsilyl)-4-(2-hydroxyethyl)-2-azetidinone 0.743 g (45%).
i.r. .mu. 2.85 (OH); 5.75, broad (.beta.-lactam)
n.m.r..delta.: 0.23, S, (CH.sub.3 Si); 0.96, S [(CH.sub.3 C-Si]; 2.0 m(C-CH.sub.2 -CH.sub.2 OH) 3.0 m (C-3H+OH); 3.64, t+m (C-4H+-CH.sub.2 -OH)
ms: M.sup.+ -57 (t Bu)=172.
EXAMPLE 11
1-(t-butyldimethylsilyl)-4-(2-oxoethyl)-2-azetidinone ##STR97##
Anhydrous CrO.sub.3 (1.94 g, 19.38 mmol) is added to a solution of anhydrous pyridine (3.07 g, 38.76 mmol; in anhydrous CH.sub.2 Cl.sub.2 (50 ml). The resulting mixture is stirred at r.t. for 15 min. A solution of 1-(t-butyldimethylsilyl)-4-(2-hydroxyethyl)-2-azetidinone (0.74 g, b 3.23 mmol) in anhydrous CH.sub.2 Cl.sub.2 5 ml is added all at once. After stirring for 5 min, the CH.sub.2 Cl.sub.2 solution is separated from a dark gummy precipitate which is washed with more CH.sub.2 Cl.sub.2. The combined CH.sub.2 Cl.sub.2 solution is evaporated under vacuum. The residue is taken up in ether filtered and washed with 5% NaHCO.sub.3, 5% HCl, 5% NaHCO.sub.3 and brine then dried and evaporated to give the aldehyde (0.543 g 74%).
i.r., .mu.: 5.75 .beta.-lactam and aldehyde
n.m.r..delta.: 0.23 S(CH.sub.3 Si); 0.99 S [(CH.sub.3).sub.3 C-Si]; 3.0 m (CH.sub.2 -CHO and C-3H); 4.0 m(C-4H); 9.76 t(CHO).
EXAMPLE 12
1-(t-butyldimethylsilyl)-4-(2-hydroxypropyl)-2-azetidinone ##STR98##
1-(t-butyldimethylsilyl)-4-(2-oxoethyl)-2-azetidinone (2.27 g, 0.01 mole) is dissolved in 50 ml ether and cooled to -20.degree. C. under N.sub.2. A solution of CH.sub.3 MgBr in ether (0.011 mole CH.sub.3 MgBr) is added dropwise over 1/2 hours at -20.degree. C. and the reaction mixture is stirred for another 1/2 hr at -20.degree., allowing to rise to 25.degree. C. The reaction mixture is treated with a saturated solution of MgSO.sub.4 (2 ml) and allowed to stir for 15 min. The Mg salts are filtered off and washed with ether. The combined filtrate and washings are dried and evaporated. Chromatography of the residue on silica gel gives 1-(t-butyldimethylsilyl)-4-(2-hydroxypropyl)-2-azetidinone.
EXAMPLE 13
1-(t-butyldimethylsilyl)-4-(2-acetoxypropyl)-2-azetidinone ##STR99##
1-(t-butyldimethylsilyl)-4-(2-hydroxypropyl)-2-azetidinone (2.46 g) is dissolved in 20 ml CH.sub.2 Cl.sub.2 cooled to 0.degree. and treated with 0.90 g pyridine and 0.080 g of acetyl chloride (added dropwise). The reaction mixture is stirred at 0.degree. for 15 min, allowed to warm to r.t. during the next 15 min and then worked up by dilution with CH.sub.2 Cl.sub.2 and washing with water, drying and evaporating. The residue on chromatography on silica gel gives 1-(t-butyldimethylsilyl)-4-(2-acetoxypropyl)-2-azetidinone.
EXAMPLE 14
4-(2-acetoxypropyl)-2-azetidinone ##STR100##
1-(t-butyldimethylsilyl)-4-(2-acetoxypropyl)-2-azetidinone (2.4 g) is dissolved in a solution of HCl in MeOH (0.25 N, 10 ml) and allowed to stand 2.5 hours at room temperature. The solvent is evaporated under reduced pressure and the residue is chromatographed on silica gel to give 4-(2-acetoxypropyl)-2-azetidinone.
EXAMPLE 15
Preparation of 4-(2-acetoxy-2-p-methoxyphenyl)-ethyl-2-azetidinone ##STR101##
Treatment of 1-(t-butyldimethylsilyl)-4-(2-oxoethyl)-2-azetidinone (0.01 mole) with p-methoxyphenyl-magnesium bromide (1.1 eq.; in ether at 0.degree. C. gives 2-azetidinone with p-methoxyphenyl-magnesium bromide gives 1-(t-butyl dimethylsilyl)-4-(2-hydroxyethyl-2-p-methoxyphenyl)-2-azetidinone which is acetylated as described before (Ex. 3, Step C) to give 4-(2-acetoxy-2-p-methoxyphenyl)-2-azetidinone.
EXAMPLE 16
Preparation of 4-(2-acetoxy-5-(1'-tetrahydropyranyloxy)-pentyl-2-azetidinone ##STR102##
Treatment (following procedure of Example 15) of 1-(t-butyldimethylsilyl)-4-(2-oxoethyl)-2-azetidinone with Grignard reagent from 1-bromo-3-(2-tetrahydropyranyloxy)-propane followed by acetylation of the product gives 4-(2-acetoxy-5-(2'-tetrahydropyranyloxy)-pentyl-2-azetidinone.
EXAMPLE b 17
Preparation of 8-Oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR103##
A solution of 4-(2'-hydroxyethyl)-2-azetidinone (1.87 g, 0.016 mole) and 2,2-dimethoxypropane (1.69 g, 0.016 mole) in 25 ml anhydrous methylene chloride is treated with boron trifluoride etherate (0.201 ml, 0.002 mole) at room temperature. The resulting solution is stirred for ten minutes. Removal of the solvent under reduced pressure gives an oil (2.5 g). Chromatography of the crude product on silica gel using 2:1 ethyl acetate/benzene as eluting solvent gives 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]-octane (1.59 g) as a crystalline solid. Recrystallization from ether/hexane gives product of m.p. 60.degree.-1.degree..
ir (CHCl.sub.3).mu.: 5.73 (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 6.02-6.28, m, 2H, C-4 methylene 6.22-6.62, m, 1H, C-6 methine 6.90, dd, 1H, J.sub.7,7 =14 Hz, J.sub.6,7 =4.5 Hz, C-7 proton cis to C-6H 7.47, dd, 1H, J.sub.7,7 =14 Hz, J.sub.6,7 =2 Hz, C-7 proton trans to C-6H 7.82-8.68, m, 2H, C-5 methylene
EXAMPLE 18
8-Oxo-2,2-dimethyl-7.beta.-(1'-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octan ##STR104##
ir (CH.sub.2 Cl.sub.2).mu.: 5.72.mu. (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 5.53-6.43, m, 4H, C-4 methylene+C-6 methine+C-9 methine 6.90, dd on broad s, 2H, J.sub.7,9 =9 Hz. J.sub.6,7 =5.5 Hz, C-7 methine+OH 7.70-8.83, m, 2H, C-5 methylene
8.78, d, 3H, J.sub.9,10 =6.5 Hz, C-10 methyl
EXAMPLE 19
Preparation of Cis-3-(1'-hydroxyethyl)-4-(2'-hydroxyethyl)-2-azetidinone ##STR105##
Following the procedure described for the preparation of trans-3-benzyl-4-(2'-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane and using 8-oxo-2,2-dimethyl-7.beta.-(1'-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octa ne one obtains cis-3-(1'-hydroxyethyl)]-4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 20
Preparation of 8-Oxo-2-methoxy-3-oxa-1-azabicyclo[4.2.0]octane ##STR106##
Following the procedure described for the preparation of 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane from 4-(2'-hydroxyethyl)-2-azetidinone and using trimethyl orthoformate instead of 2,2-dimethoxypropane one obtains 8-oxo-2-methoxy-3-oxa-1-azabicyclo[4.2.0]octane.
i.r. (CHCl.sub.3).mu.: 5.69 (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 4.30, s, 1H, C-2 methine 5.67-6.43, m, 3H, C-4 methylene+C-6 methine 6.62, s, 3H, OCH.sub.3 6.75, dd, 1H, J.sub.7,7 =16 Hz, J.sub.6,7 =5 Hz, C-7 methylene proton cis to C-6 H 7.33, dd, 1H, J.sub.7,7 =16 Hz, J.sub.6,7 =2 Hz, C-7 methylene proton trans to C-6H 7.70-8.65, m, 2H, C-5 methylene
EXAMPLE 21
Preparation of 8-Oxo-2-methoxy-7.alpha. and .beta.-benzoyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR107##
To a solution of 1.1 equivalent of freshly prepared lithium diisopropylamide in 4 ml anhydrous tetrahydrofuran under nitrogen atmosphere at -78.degree. is added a solution of 8-oxo-2-methoxy-3-oxa-1-azabicyclo[4.2.0]octane (56 mg, 0.357 mmole) in 1 ml anhydrous tetrahydrofuran which has been cooled to -78.degree.. After two minutes the resulting lithium enolate is treated with methyl benzoate (49 mg, 0.357 mmole) and the solution allowed to warm to 0.degree. over a 15 min period. The solution is then poured into water and the aqueous phase is saturated with sodium chloride and extracted with methylene chloride. The combined methylene chloride solutions are dried over magnesium sulphate, filtered and the filtrate evaporated under reduced pressure to give 94 mg of crude product. Purification by preparative thick-layer chromatography on silica gel developing with ether gives 8-oxo-2-methoxy-7.alpha. and .beta.-benzoyl-3-oxa-1-azabicyclo[4.2.0]octane as a mixture.
ir (CHCl.sub.3).mu.: 5.67 (.beta.-lactam); 5.96 (benzoyl)
nmr (CDCl.sub.3).tau.: 1.73-2.05, m, 2H, ArH 2.33-2.63, m, 3H, ArH 4.28, s, 1H, C-2 methine 5.37 and 5.40, two overlapping d's, 1H, J.sub.6,7 .alpha.=4 Hz, J.sub.6,7 .beta.=2 Hz, C-7.alpha. and .beta. methine 5.47-5.77, m, 1H, C-6 methine 6.00-6.37, m, 2H, C-4 methylene 6.67, s, 3H, OCH.sub.3 7.80-8.13, m, 2H, C-5 methylene
EXAMPLE 22
Preparation of Cis and Trans-1-Formyl-3-benzoyl-4-(2'-hydroxyethyl)-2-azetidinone ##STR108##
A solution of 8-oxo-2-methoxy-7.alpha. and .beta.-benzoyl-3-oxa-1-azabicyclo[4.2.0]octane in aqueous p-dioxane containing 0.1 molar equivalent of concentrated sulfuric acid is stirred at room temperature for a period of 80 minutes. The solution is neutralized with 5% sodium bicarbonate solution and extracted with methylene chloride. The combined organic solutions are dried over magnesium sulfate, filtered and the filtrate is evaporated under reduced pressure to give cis and trans-1-formyl-3-benzoyl-4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 23
Preparation of Cis and Trans-3-Benzoyl-4-(2'-hydroxyethyl)-2-azetidinone ##STR109##
A solution of cis and trans-1-formyl-3-benzoyl-4-(2'-hydroxyethyl)-2-azetidinone in p-dioxane is treated at room temperature (25.degree. C.) with an aqueous solution of 1 equivalent of sodium bicarbonate. The resulting solution is stirred for a period of two hours. It is then acidified by addition of 1 M pH 3 phosphate buffer. The product is extracted with ethylacetate washing with brine. The ethyl acetate solution is then dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives a mixture of cis and trans-3-benzoyl-4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 24
Preparation of 8-Oxo-2,2-dimethyl-7.alpha. and .beta.-hydroxyisopropyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR110##
The lithium enolate of 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane (40 mg., 0.258 mmole) is prepared as described in the preparation of 8-oxo-2,2-dimethyl-7.alpha.-isopropyl-3-oxa-1-azabicyclo[4.2.0]octane. The enolate at -78.degree. is treated with excess acetone. After 5 minutes at -78.degree. the reaction is quenched by pouring the reaction mixture into water. The aqueous phase is saturated with sodium chloride and extracted with methylene chloride. The combined methylene chloride solutions are dried over magnesium sulfate, filtered and the filtrate evaporated under reduced pressure to give 48 mg of crude product. Purification by preparative thick-layer chromatography on silica gel developing with 10% methanol/chloroform gives 8-oxo-2,2-dimethyl-7.alpha. and .beta.-hydroxyisopropyl-3-oxa-1-azabicyclo[4.2.0]octane (23 mg and 3 mg, respectively).
7.alpha.-diasteromer: ir (CHCl.sub.3).mu. 5.75 (.beta.-lactam) nmr (CDCl.sub.3).tau. 6.0-6.23, m, 2H, C-4 methylene 6.27-6.60, m, 1H, C-6 methine 7.13, d, 1H, J.sub.6,7 =1.9 Hz, C-7 methine 7.97-8.60, m, 2H, C-5 methylene 8.03, s, 1H, OH
7.beta.-diastereomer: ir(CHCl.sub.3).mu. 5.74 (.beta.-lactam) nmr(CDCl.sub.3).tau. 6.06-6.44, m, C-4 methylene+C-6 methine 6.79, d, J.sub.6,7 =5 Hz, C-7 methine 8.0-8.6, m, C-5 methylene
EXAMPLE 25
Preparation of Trans-3-hydroxyisopropyl-4-(2'-hydroxyethyl)-2-azetidinone ##STR111##
Following the procedure described for the preparation of trans-3-benzyl-4-(2'-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane and using 8-oxo-2,2-dimethyl-7.alpha.-hydroxyisopropyl-3-oxa-1-azabicyclo[4.2.0]octa ne one obtains trans-3-hydroxyisopropyl-4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 25a
Preparation of Cis-3-hydroxyisopropyl-4-(2'-hydroxyethyl)-2-azetidinone ##STR112##
Following the procedure described for the preparation of trans-3-benzyl-4-(2-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane and using 8-oxo-2,2-dimethyl-7.beta.-hydroxyisopropyl-3-oxa-1-azabicyclo[4.2.0]octan e one obtains cis-3-hydroxyisopropyl 4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 26
Preparation of 8-Oxo-7-acetoxymethylene-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR113##
To a solution of 2.0 equivalents of freshly prepared lithium diisopropylamide in 5 ml anhydrous tetrahydrofuran under nitrogen atmosphere at -78.degree. is added a solution of 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane (98 mg., 0.629 mmole) in 2 ml anhydrous tetrahydrofuran which has been cooled to -78.degree.. After two minutes excess anhydrous N,N-dimethylformamide (460 mg, 6.29 mmole) is added followed immediately by distilled and degassed acetyl chloride (148 mg, 1.89 mmole) which has been cooled to -78.degree.. After stirring at -78.degree. for a period of 5 minutes, the reaction mixture is poured into 0.2 M pH 7 phosphate buffer. The product is extracted with methylene chloride. The combined methylene chloride solutions are dried over magnesium sulfate, filtered and the filtrate evaporated under reduced pressure to give 64 mg of a colorless oil. Purification by preparative thick-layer chromatography on silica gel developing twice with ether gives 8-oxo-7 -acetoxymethylene-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane (25 mg).
ir (CHCl.sub.3).mu.: 5.65 (.beta.-lactam), 5.75 (ester), 5.89 (C.dbd.C)
nmr (CDCl.sub.3).tau.: 2.42, d, 1H, J.sub.6,9 =1 Hz, C-9 vinyl 5.87, dd further split by C-9 vinyl proton, 1H, J.sub.5,6 =10 Hz and 6 Hz, J.sub.6,9 =1 Hz, C-6 methine 6.07-6.30, m, 2H, C-4 methylene 7.82, s, 3H, OCOCH.sub.3 ##STR114## 7.77-8.67, m, 2H, C-5 methylene
EXAMPLE 27
Preparation of 8-Oxo-7-(1'-acetoxyethylidene)-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octan ##STR115##
Following the procedure described for the preparation of 8-oxo-7-acetoxymethylene-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane from 8-oxo-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane and using N,N-dimethylacetamide instead of N,N-dimethylformamide one obtains 8-oxo-7-(1'-acetoxyethylidene)-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octan e.
ir (CHCl.sub.3).mu.: 5.67 (.beta.-lactam), 5.72 (ester), 5.90 (C.dbd.C)
nmr (CDCl.sub.3): 5.53-6.00, m, 1H, C-6 methine 6.02, m, 2H, C-4 methylene 7.53-8.73, m, 2H, C-5 methylene ##STR116##
EXAMPLE 28
Preparation of 8-Oxo-2,2,7.beta.-trimethyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR117##
A solution of 8-oxo-7-acetoxymethylene-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octane (38 mg, 0.169 mmole) in 5 ml of ethyl acetate containing 4 mg of platinum oxide is hydrogenated at room temperature and 40 psi hydrogen for a period of 35 minutes. The reaction mixture is filtered through a bed of supercel washing with additional ethyl acetate. Evaporation of the filtrate under reduced pressure gives 31 mg of crude product. Purification by preparative thick-layer chromatography developing with 2:1 ethyl acetate/benzene gives 8-oxo-2,2,7.beta.-trimethyl-3-oxa-1-azabicyclo[4.2.0]octane (13 mg).
ir (CHCl.sub.3).mu.: 5.74 (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 6.04-6.20, m, C-4 methylene 6.28, sextet partially covered by above m, J=10 Hz and 5.2 Hz; C-6 methine 6.71, m, J=7.6 Hz and 5.2 Hz, C-7 methine 7.92-8.84, m, C-5 methylene ##STR118## 8.80, d, J=7.5 Hz
EXAMPLE 29
Preparation of cis-3-methyl-4-(2'-hydroxyethyl)-2-azetidinone ##STR119##
Following the procedure described for the preparation of trans-3-benzyl-4-(2-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane and using 8-oxo-2,2-dimethyl-7.beta.-methyl-3-oxa-1-azabicyclo[4.2.0]octane one obtains cis-3-methyl-4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 30
Preparation of 8-Oxo-2,2-dimethyl-7.beta.-ethyl-3-oxa-1-azabicyclo[4.2.0]octane ##STR120##
A solution of 8-oxo-7-(1'-acetoxyethylidene)-2,2-dimethyl-3-oxa-1-azabicyclo[4.2.0]octan e (11 mg, 0.846 mmole) in 2 ml ethyl acetate and 0.2 ml methanol containing 10 mg of platinum oxide is hydrogenated at room temperature and 40 psi hydrogen for a period of 60 minutes. The reaction mixture is filtered through a bed of supercel washing with additional ethyl acetate. Evaporation of the filtrate under reduced pressure gives 8 mg of crystalline product. Purification by preparative thick-layer chromatography developing twice with ether gives 8-oxo-2,2-dimethyl-7.beta.-ethyl-3-oxa-1-azabicyclo[4.2.0]octane (6 mg).
ir (CHCl.sub.3).mu.: 5.74 (.beta.-lactam)
nmr (CDCl.sub.3).tau.: 6.06-6.22, m, C-4 methylene 6.26, sextet partially under above m; J=10.5 Hz, 10.5 Hz and 5.5 Hz; C-6 methine 6.90, m; J=8.5 Hz, 7 Hz, 5.5 Hz; C-7 methine 7.94-8.89, m, C-5 methylene+C-9 methylene ##STR121## 9.02, t, J=7 Hz, CH.sub.3 CH.sub.2
EXAMPLE 31
Preparation of Cis-3-Ethyl-4-(2'-hydroxymethyl)-2-azetidinone ##STR122##
Following the procedure described for the preparation of trans-3-benzyl-4-(2-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]octane and using 8-oxo-2,2-dimethyl-7.beta.-ethyl-3-oxa-1-azabicyclo[4.2.0]octane one obtains cis-3-ethyl-4-(2'-hydroxyethyl)-2-azetidinone.
EXAMPLE 32
Preparation of 1-(t-butyldimethylsilyl)-3-acetyl-4-(2'-hydroxyethyl)-2-azetidinone ##STR123##
To a solution of 1.1 equivalents of freshly prepared lithium diisopropylamide in 3 ml anhydrous tetrahydrofuran under a nitrogen atmosphere at -78.degree. is added a solution of 1-(t-butyldimethylsilyl)-4-(2'-acetoxyethyl)-2-azetidinone (61 mg. 0.225 mmole) in 1 ml anhydrous tetrahydrofuran which has been cooled to -78.degree.. After 12 minutes the reaction mixture is poured into 5 ml water. The solution is saturated with sodium chloride and extracted with methylene chloride. The combined methylene chloride solutions are washed with brine, dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives 50 mg of crude product. Purification by preparative thick-layer chromatography on silica gel developing with ethyl acetate gives 1-(t-butyldimethylsilyl)-3-acetyl-4-(2'-hydroxyethyl)-2-azetidinone (19 mg).
ir (CHCl.sub.3).mu.: 5.73 (.beta.-lactam), 5.83 (ketone)
nmr (CDCl.sub.3).tau.: 5.88-6.57, m, 4H, C-3 methine+C-4 methine+CH.sub.2 CH.sub.2 OH 7.55-8.85, m, 3H, CH.sub.2 CH.sub.2 OH 7.68, s, 3H, CH.sub.3 CO 9.05, s, 9H, SiC(CH.sub.3).sub.3 ##STR124## 6H, Si(CH.sub.3).sub.2.
EXAMPLE 33
Preparation of 8-Oxo-2,2-dimethyl-7.alpha.-(1'-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-a zabicyclo[4.2.0]octane ##STR125##
Under anhydrous conditions at 0.degree., a solution of 8-oxo-2,2-dimethyl-7.alpha.-(1'-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]oct ane (60 mg, 0.302 mmole) in 0.6 ml ether is treated with powdered potassium hydroxide (19 mg, 0.332 mmole). After a period of 15 minutes, p-nitrobenzyl chloroformate (65 mg, 0.302 mmole) is added to the reaction mixture. Stirring is continued at room temperature for an additional 15 hours. The mixture is partitioned between 1 M pH 7 phosphate buffer and more ether. The ether phase is washed with water and brine, dried over magnesium sulfate and filtered. Evaporation of the filtrate under reduced pressure gives 67 mg of a colorless oil. Purification by preparative thick-layer chromatography on silica gel developing with 1:9 ethyl acetate/benzene gives 8-oxo-2,2-dimethyl-7.alpha.-(t'-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-a zabicyclo[4.2.0]octane (40 mg) as a mixture of diastereomers.
ir (CH.sub.2 Cl.sub.2) .mu.: 5.68 (.beta.-lactam and carbonate), 6.19 and 6.54 (nitro)
nmr(CDCl.sub.3).tau.: 1.67, d, 2H, ArH 2.37, d, 2H, ArH 4.67, s, 2H, ArCH.sub.2 4.67-5.22, m, CH.sub.3 CH 5.98-6.25, m, 2H, C-4 methylene 6.25-6.62, m, 1H, C-6 methine 6.75-7.12, m, 1H, C-7 methine 7.75-8.83, m, 2H, C-5 methylene 8.22, s, 3H, C-2 methyl 8.50-8.58, m, 5H, C-2 methyl+CH.sub.3 CH
EXAMPLE 34
Preparation of Trans-3-(1'-p-nitrobenzylcarbonyldioxyethyl)-4-(2'-hydroxyethyl)-2-azetidi none ##STR126##
Following the procedure described for the preparation of trans-3-benzyl-4-(2'-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]-octane and using 8-oxo-2,2-dimethyl-7.alpha.-(1'-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-10- azabicyclo[4.2.0]octane one obtains trans-3-(1'-p-nitrobenzylcarbonyldioxyethyl)-4-(2'-hydroxyethyl)-2-azetidi none.
ir (CH.sub.2 Cl.sub.2).mu.: 5.67 (.beta.-lactam), 5.72 shoulder, 6.20 and 6.57 (nitro)
nmr (CDCl.sub.3): 1.73, d, 2H, J=8.5 H.sub.z, ArH 2.43, d, 2H, J=8.5H.sub.z, ArH 3.63, broad s, 1H, NH 4.37-5.13, m, 1H, CH.sub.3 CH 4.72, s, 2H, ArCH.sub.2 6.07-6.53, m, 1H, C-4 methine 6.23, t, 2H, J=5.5H.sub.z, CH.sub.2 OH 6.73-6.93, m, 1H, C-3 methine 7.63-8.97, m, 3H, CH.sub.2 CH.sub.2 OH 8.53, d, J=6.5H.sub.z, CH.sub.3 CH
EXAMPLE 35
Preparation of 8-Oxo-2,2-dimethyl-7.beta.-(1'-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-az abicyclo[4.2.0]octane ##STR127##
Following the procedure described for the preparation of 8-oxo-2,2-dimethyl-7.alpha.-(1'-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-a zabicyclo[4.2.0]octane from 8-oxo-2,2-dimethyl-7.alpha.-(1'-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]oct ane and using 8-oxo-2,2-dimethyl-7.beta.-(1'-hydroxyethyl)-3-oxa-1-azabicyclo[4.2.0]octa ne one obtains 8-oxo-2,2-dimethyl-7.beta.-(1'-p-nittobenzylcarbonyldioxyethyl)-3-oxa-1-az abicyclo[4.2.0]octane.
EXAMPLE 36
Preparation of Cis-3-(1'-p-nitrobenzylcarbonyldioxyethyl)-4-(2'-hydroxyethyl)-2-azetidino ne ##STR128##
Following the procedure described for the preparation of trans-3-benzyl-4-(2'-hydroxyethyl)-2-azetidinone from 8-oxo-2,2-dimethyl-7.alpha.-benzyl-3-oxa-1-azabicyclo[4.2.0]-octane and using 8-oxo-2,2-dimethyl-7.beta.-(1'-p-nitrobenzylcarbonyldioxyethyl)-3-oxa-1-az abicyclo[4.2.0]-octane one obtains cis-3-(1'-p-nitrobenzylcarbonyldioxyethyl)-4-(2'-hydroxyethyl)-2-azetidino ne.
EXAMPLE 37
Following the procedures of the foregoing Examples, text and the footnotes to Table II (below), the following substituted azetidinones of the present invention are obtained.
EXAMPLE 38
Following the procedures developed in the foregoing Examples and text, the following compounds (I) are obtained. Remarks relative to procedure are presented in the footnote to Table III.
EXAMPLE 39
Preparation of Pharmaceutical Compositions
One such unit dosage form consists in mixing 120 mg. of 1-carba-2-penem-3-carboxylic acid with 20 mg. of lactose and 5 mg. of magnesium stearate and placing the 145 mg. mixture into a No. 3 gelatin capsule. Similarly, by employing more of the active ingredient and less lactose, other dosage forms can be put up in No. 3 gelatin capsules and should it be necessary to mix more than 145 mg. of ingredients together, larger capsules such as compressed tablets and pills can also be prepared. The following examples are illustrative of the preparation of pharmaceutical formulations:
The active ingredient is blended with the dicalcium phosphate, lactose and about half of the cornstarch. The mixture is then granulated with 15% cornstarch paste (6 mg.) and rough-screened. It is dried at 45.degree. C. and screened again through No. 16 screens. The balance of the cornstarch and the magnesium stearate is added and the mixture is compressed into tablets, approximately 0.5 inch in diameter each weighing 800 mg.
The active ingredient in the above formulations may be administered alone or in combination with other biologically active ingredients as, for example, with other antibacterial agents such as lincomycin, a penicillin, streptomycin, novobiocin, gentamicin, neomycin, colistin and kanamycin, or with other therapeutic agents such as probenecid.
Claims
What is claimed is:
1. The compound having the formula ##STR215## wherein R is hydrogen, acetyl, bromo-t-butoxy carbonyl, benzyloxycarbonyl, formyl, trifluoroacetyl, trimethylsilyl, or t-butyl dimethylsilyl; R.sup.1 and R.sup.3 are independently selected from the group consisting of hydrogen; alkyl of 1-6 carbon atoms; or the group ##STR216## wherein R is as defined; phenylalkyl, the alkyl chain of which is 1-6 carbon atoms; and phenyl.
2. The compound of claim 1 wherein R.sup.3 is hydrogen and R.sup.1 is ##STR217## wherein R is hydrogen, acetyl, bromo-t-butoxy carbonyl, benzyloxycarbonyl, formyl, trifluoroacetyl, trimethylsilyl, or t-butyl dimethylsilyl.
3. The compound of claim 2 wherein R.sup.1 is ##STR218##
4. The compound of claim 2 wherein R.sup.1 is ##STR219## wherein R is acetyl, bromo-t-butoxy carbonyl, benzyloxycarbonyl, formyl, trifluoroacetyl, trimethylsilyl, or t-butyl dimethylsilyl.
5. The compound which is ##STR220##
6. The compound which is ##STR221##
Patent Citations (1)
| Patent | Date | Inventor | Cited By |
|---|---|---|---|
| US3950357 | 1976-04-01 | Kahan et al. |
Non-Patent Literature (3)
- Wagner et al., Synthetic Organic Chemistry, (New York, 1953), pp. 159-161.
- Zabicky, The Chemistry of Amides, (Interscience, N.Y., 1970), pp. 752-753.
- Testa et al., Chem. Abstracts., vol. 58, cols. 11312-11313 (1963).