US 4,029,676 AGrant
Esters of Tetrahydronaphthyloxy-Aminopropanols
Issue Date:1977-06-14
•6 Claims
Abstract
Compounds having the formula ##STR1## wherein R.sup.1 is lower alkyl; R.sup.3, R.sup.4, R.sup.5, R.sup.6, and R.sup.7 are the same or different and are hydrogen or lower alkyl; R.sup.8, R.sup.9, and R.sup.10 are the same or different and are hydrogen, lower alkyl, lower alkoxy or cycloalkyl; and R.sup.11 is acyl; are useful in the treatment of coronary diseases.
Metadata
Assignee
- E. R. Squibb & Sons, Inc.
Inventors
- Frederic P. Hauck
- Christopher M. Cimarusti
- Venkatachala L. Narayanan
Application Information
Application Number:US 629734&
Filing Date:1975-11-06
Priority Date:1970-06-22
Art Unit:127
Classifications
IPC:
C07C 9300C07D30762
Field of Search:
260490;477;404;404.5;472;343.7;570.7;473 R
Patent Drawings
This patent does not have any drawings.
Description
SUMMARY OF THE INVENTION
This invention relates to new chemical compounds of the formula ##STR2## and salts of such compounds. In formula I, and throughout the specification, the symbols are as defined below.
R.sup.1 can be lower alkyl;
R.sup.3,r.sup.4,r.sup.5,r.sup.6, and R.sup.7 can be the same or different and can be hydrogen or lower alkyl;
R.sup.8, r.sup.9, and R.sup.10 can be the same or different and can be hydrogen, lower alkyl, monocyclic aryl-lower alkyl, lower alkoxy, carboxy or monocyclic cycloalkyl; and
R.sup.11 can be acyl.
The term "lower alkyl" as used throughout the specification, includes both straight and branched chain radicals of up to and including eight carbon atoms, e.g., methyl, ethyl, propyl, isopropyl, butyl, s-butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl and the like.
The term "lower alkoxy" as used throughout the specification, includes straight and branched chain radicals of the structure RO-- wherein R includes any of the above lower alkyl groups.
The term "monocyclic aryl", as used throughout the specification, includes phenyl and phenyl substituted with lower alkyl, lower alkoxy, halogen or nitro groups. Exemplary substituted phenyl groups are lower alkyl phenyl (e.g., o-, m-, or p-tolyl, ethylphenyl, butylphenyl and the like); di(lower alkyl)phenyl (e.g., 2,4-dimethylphenyl, 3,5-diethylphenyl, and the like); halophenyl (e.g., chlorophenyl, bromophenyl, iodophenyl, or fluorophenyl); o-, m- or p-nitrophenyl; dinitrophenyl (e.g., 3,5-dinitrophenyl, 2,6-dinitrophenyl, and the like); and trinitrophenyl (e.g., picryl).
The term "monocyclic aryl-lower alkyl", as used throughout the specification refers to lower alkyl groups (as defined above) substituted with a monocyclic aryl group (as defined above). Included within the term are benzyl and phenethyl.
The term "acyl", as used throughout the specification, refers to fatty acid radicals having the formula ##STR3## wherein n is an integer of from 1 to 11 (e.g., acetyl, propionyl, butyryl, isobutyryl, hexanoyl, heptanoyl, decanoyl, dodecanoyl, and the like); acyl groups derived from monocyclic aryl carboxylic acids, i.e., groups having the formula ##STR4## wherein X is monocyclic aryl as defined above (e.g., phenyl, o-tolyl, p-nitrophenyl, and the like); and acyl groups derived from aralkanoic acids, i.e., groups having the formula ##STR5## wherein Z is monocyclic aryl-lower alkyl as defined above (e.g., benzyl, 3-phenylpropyl, 3-(p-chlorophenyl)butyl, and the like).
The term "monocyclic cycloalkyl", as used throughout the specification, refers to cycloalkyl groups having 3 to 6 ring members (e.g., cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl).
The compounds of formula I form acid addition salts with inorganic and organic acids. These acid addition salts frequently provide useful means for isolating the products from reaction mixtures by forming the salt in a medium in which it is insoluble, and then neutralizing the salt with a base such as sodium hydroxide to obtain the free base. Any other salt may then be formed from the free base and the appropriate inorganic or organic acid. Illustrative are the hydrohalides, especially the hydrochloride and hydrobromide which are preferred, sulfate, nitrate, phosphate, borate, acetate, oxalate, tartrate, maleate, citrate, succinate, benzoate, ascorbate, salicyclate, methanesulfonate, benzenesulfonate, toluenesulfonate, and the like. Quaternary ammonium salts are also formed, e.g., by reacting the free base with an alkylating agent such as a lower alkyl halide (e.g., methyl chloride, ethyl bromide, or the like), a lower alkyl sulfate (e.g., methyl sulfate), a monocyclic aryllower alkyl halide (e.g., benzyl chloride) or a monocyclic aryllower alkyl sulfate (e.g., benzyl sulfate), or the like.
Those compounds wherein R.sup.3,R.sup.4,R.sup.5,R.sup.6,R.sup.7,R.sup.8,R.sup.9, and R.sup.10 are all hydrogen are preferred.
The compounds of this invention are useful as anti-fibrillatory agents, for example, in arresting cardiac arrhythmia in mammals, e.g., by inhibition of beta adrenergic receptors in the myocardium. For this purpose a compound of formula I or a physiologically acceptable acid addition salt may be incorporated in a conventional dosage form such as a tablet capsule, elixir, injectable or the like along with the necessary carrier material, excipient, lubricant, buffer, or the like. Single or divided doses of about 5 to 25 mg/kg, preferably about 4 to 10 mg/kg, two to four times daily may be administered in dosage forms as described above.
Examples of compounds falling within the present invention include, but are not limited to, the following: ##STR6##
The compounds of formula I are prepared from the corresponding 1,2,3,4-tetrahydro-2,3-naphthalenediol having the formula ##STR7## The procedure comprises first protecting the hydroxy group in the aminopropoxy side chain of a compound of formula II, acylating the remaining two hydroxy groups, and finally, removing the protecting group.
Various means for protecting the hydroxy group in the aminopropoxy side chain of a compound of formula II will be apparent to the practitioner of this invention. An exemplary method comprises reacting a compound of formula II with an aldehyde having the formula
wherein R.sup.12 is lower alkyl or monocyclic aryl to yield an oxazolidine derivative having the formula ##STR8## The reaction can be run in an organic solvent, preferably at the reflux temperature of the solvent.
An oxazolidine derivative of formula IV can be acylated with an acid anhydride having the formula
or an acid chloride having the formula
using procedures well known in the art to yield a compound having the formula ##STR9##
Catalytic reduction of a compound of formula VII using gaseous hydrogen and a catalyst such as platinum oxide or palladium yields the corresponding compound of formula I.
The compounds of formula I include those wherein the two acyloxy groups (R.sup.11 O--) are in the cis and in the trans configuration. Depending on which configuration it is desired to prepare, the corresponding 2,3-trans (or cis)-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(alkylamino)propoxy]-2,3-naphthalen ediol of formula II is used as the precursor.
A 2,3-trans (or cis)-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(alkylamino)propoxy]-2,3-naphthalen ediol of formula II can be prepared by first reducing a naphthol having the formula ##STR10## with a metal such as sodium or lithium in liquid ammonia containing an alkanol such as ethanol, isopropanol, t-butanol or the like [e.g., by the procedure described in Organic Synthesis Coll. Vol. 4, page 887 (1963)] to obtain a 5,8-dihydronaphthol of the formula ##STR11## A 5,8-dihydronaphthol of formula IX can be converted to the corresponding acetate having the formula ##STR12## by dissolving it in acetic anhydride and an organic base such as pyridine.
A trans-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol can be prepared from an acetate of formula X by dissolving the acetate in acetic acid, and then treating the solution with from about 2 to about 4 equivalents of silver acetate and from about 1 to about 2 equivalents of iodine. The mixture is then heated at a temperature of from about 80.degree. to about 120.degree. C. for a period of from about 1 to about 24 hours under nitrogen, to yield a trans-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol having the formula ##STR13## after basic hydrolysis.
A compound of formula XI can be converted to a 2,3-trans-1,2,3,4-tetrahydro-5-[2,3-(epoxy)propoxy]-2,3-naphthalene-diol of the formula ##STR14## by reacting a naphthalenetriol of formula XI with an alkali metal alkoxide (e.g., sodium methoxide) in an alcohol solvent boiling below about 100.degree. C. (e.g., methanol) under nitrogen, and then, after removal of the solvent, stirring the residue in a dipolar aprotic solvent such as dimethylsulfoxide, hexamethylphosphoramide or dimethylformamide, with an epoxide having the formula ##STR15## under nitrogen.
The 2,3-trans-1,2,3,4,-tetrahydro-5-[2,3-(epoxy)propoxy]-2,3-naphthalenediol o f formula XII is then reacted with an alkylamine having the formula
to form 2,3-trans-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(alkylamino)-propoxy]-2,3-naph thalenediol of formula II.
The corresponding cis isomer of formula II can be prepared by dissolving a dihydronaphthalene acetate of formula X in acetic acid and water (from 92 to 98% acetic acid, preferably 96% acetic acid), and then treating the solution with silver acetate and iodine and heating under nitrogen (as described for the preparation of the trans-isomer) to form the cis-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol having the formula ##STR16## after basic hydrolysis. A compound of formula XV can be converted to the 2,3-cis-1,2,3,4-tetrahydro-5-[2,3-(epoxy)propoxy]-2,3-naphthalenediol, which in turn can be converted to the 2,3-cis-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(alkylamino)-propoxy]-2,3-naphth alenediol in a manner similar to that described with respect to the preparation of the corresponding trans isomer.
Alternatively, the 2,3-trans-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(alkylamino)propoxy]-2,3-napht halenediol of formula II can be prepared from a 5,8-dihydro-1-naphthol of formula IX by mixing a cooled solution (temperature less than about 30.degree. C.) of 5,8-dihydro-1-naphthol in ethyl acetate with m-chloroperbenzoic acid and mixing the resulting slurry with a mixture of ethyl ether and aqueous sodium bicarbonate, to form a 5,6,7,8-tetrahydro-6,7-epoxy-1-naphthol having the formula ##STR17## A 5,6,7,8-tetrahydro-6,7-epoxy-1-naphthol of formula XVI in tetrahydrofuran can be reacted with aqueous perchloric acid at a temperature within the range of from about 0.degree. to about 60.degree. C., to form a trans-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol or formula XI which can be converted to the corresponding 2,3-trans-1,2,3,4-tetrahydro-5-[2,3-(epoxy)propoxy]-2,3-naphthanediol of formula XII, which in turn can be converted to the corresponding 2,3-trans-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(alkylamino)propoxy]-2,3-napht halenediol of formula II using the procedures described above.
The following examples further illustrate the invention.
EXAMPLE 1
5-[3-[(1,1-Dimethylethyl)amino]-2-hydroxypropoxy]-1,2,3,4-tetrahydro-cis-2, 3-naphthalalenediol, diacetate ester, hydrochloride (1:1)
(a). cis-5,6,7,8-Tetrahydro-1,6,7-naphthalenetriol
A solution of 29.2 g. of 5,8-dihydro-1-naphthol and 40 ml of acetic anhydride in 100 ml of pyridine is prepared. After 16 hours the solvent is removed in vacuo and the residue is dissolved in ether and washed with 200 ml of 5% hydrochloric acid, water, 200 ml of 10% sodium hydroxide, saturated salt solution and dried. Solvent removal gives 34.2 g of crude acetate which is dissolved in 900 ml of acetic acid and 36 ml of water. Silver acetate (53.3 g) is added followed by 40.6 g of iodine. The slurry is heated with good stirring at 85.degree..+-. 10.degree. C. for 3 hours under nitrogen, cooled and filtered. The filtrate is evaporated in vacuo and the residue dissolved in 250 ml of methanol and cooled to 0.degree. C. A solution of 40 g of sodium hydroxide in 200 ml of water is added under nitrogen and the mixture is stirred overnight. The bulk of the methanol is removed in vacuo whereupon a solid forms. The solid is separated by filtration, dissolved in 150 ml of water and acidified with 20 ml of concentrated hydrochloric acid. Cooling gives a solid which is filtered and dried to give 16.5 g cis-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol melting point 184.5.degree.-187.degree. C. Three recrystallizations from absolute ethanol give the analytical sample, melting point 188.degree.-188.5.degree. C.
(b). 2,3-cis-1,2,3,4-Tetrahydro-5-[2,3-(epoxy)propoxy]-2,3-naphthalenediol
A solution of 1.20 g of sodium methoxide and 5.4 g of cis-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol in 200 ml of methanol is prepared under nitrogen. The residue obtained upon solvent removal is stirred overnight with 200 ml of dimethylsulfoxide and 4.65 g of epichlorohydrin under nitrogen. The bulk of the solvent is removed at 50.degree. C. at 0.1 mm and the residue is dissolved in 100 ml of water. Extraction with chloroform (ten 200 ml portions) gives a solid which is recrystallized from 150 ml of hexane-ethyl acetate to give the title compound.
(c). 2,3-cis-1,2,3,4-Tetrahydro-5-[2-hydroxy-3-(tertbutylamino)propoxy]-2,3-nap hthalenediol
A mixture of 3.0 g of 2,3-cis-1,2,3,4-tetrahydro-5-[2,3-(epoxy)propoxy]-2,3-naphthalenediol (melting point 104.degree.-107.degree. C., one spot on TLC--alumina, 5% methanol in chloroform, iodine visualization) and 22 ml of t-butylamine is heated at 85.degree.-95.degree. C. for 15 hours in a Parr bomb and the excess amine is removed in vacuo. The solid obtained by trituration of the residue with ether is filtered and recrystallized from benzene to give 3.4 g of the title compound, melting point 124.degree.-136.degree. C.
(d). 2,3-cis-5-[[3-(1,1-Dimethylethyl)-2-phenyl-5-oxazolidinyl]methoxy]-1,2,3,4 -tetrahydro-2,3-naphthalenediol
Benzaldehyde (26.6 g) is added to a suspension of 15.5 g of 2,3-cis-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(tert-butylamino)-propoxy]-2,3-n aphthalenediol in 400 ml of xylene, and the mixture is stirred at reflux for 48 hours with a Dean-Stark trap in the system. The solvent is removed in vacuo to give 20 g of dense oil residue. The material is chromatographed on 300 g of neutral Alumina III to give 1.1 g of forerun (benzaldehyde) eluted with benzene; and 10.5 g of the title compound product eluted with 50-100% chloroform-benzene and 5% methanol-chloroform.
(e). 2,3-cis-5-[[3-(1,1-Dimethylethyl)-2-phenyl-5-oxazolidinyl]methoxy]-1,2,3,4 -tetrahydro-2,3-naphthalenediol, diacetate ester
Acetic anhydride (8.8 g) is added to a solution of 10.5 g of 2,3-cis-[[3-(1,1-dimethylethyl)-2-phenyl-5-oxazolidinyl]methoxy]-1,2,3,4-t etrahydro-2,3-naphthalenediol in 150 ml of dry pyridine and the solution is stirred for 6 hours at room temperature. The solution is diluted with 4 ml of methanol, stirred for 10 minutes and then evaporated in vacuo. The residue is chromatographed on 200 g of neutral Alumina III eluted with 1:1 ethyl acetate-hexane. The diacetate product (4.6 g) is obtained in the initial 200 ml of eluent. An additional 400 ml of eluent gives 4.7 g of material which appears to be the mono-acetylated intermediate. The latter material is further treated with acetic anhydride-pyridine for 18 hours, to give, on workup, 5.0 g of the desired diacetate. This is combined with the 4.6 g of diacetate from the column to give 9.6 g of the title compound.
(f). 5-[3-[(1,1-Dimethylethyl)amino]-2-hydroxypropoxy]-1,2,3,4-tetrahydro-cis-2 ,3-naphthalenediol, hydrochloride (1:1 )
Palladium on carbon (8 g, 5%) is added to a solution of 8.4 g of 2,3-cis-[[3-(1,1-dimethylethyl)-2-phenyl-5-oxazolidinyl]methoxy]-1,2,3,4-t etrahydro-2,3-naphthalenediol, diacetate ester in 500 ml of absolute ethanol and the mixture placed on a Parr shaker under 54 psi of hydrogen for 23 hours. The mixture is filtered, the catalyst washed with 150 ml of absolute ethanol, and the combined filtrates evaporated in vacuo to give 6.5 g of crude product. Chromatography on 150 g of neutral Alumina III gives 3.5 g of forerun material (eluted with 650 ml of 40-75% chloroform in benzene) and then 2.4 g of the desired product (eluted with 75-100% chloroform in benzene). The product is converted to its hydrochloride salt and recrystallized from isopropanolether to give 1.4 g of the title compound, melting point 170.degree.-197.degree. C.
EXAMPLES 2-7
Following the procedure of Example 1, but substituting the compound listed in column I for 5,8-dihydro-1-naphthol, the compound listed in column II for t-butylamine, and the compound listed in column III for the acetic anhydride acylating agent in Example 1(e), yields the compound listed in column IV.
EXAMPLE 8
5-[2-Hydroxy-3-(isopropylamino)propoxy]-1,2,3,4-tetrahydrotrans-2,3-naphtha lenediol, diacetate ester
(a). 5,6,7,8-Tetrahydro-6,7-epoxy-1-naphthol
An amount of 25.0 g of m-chloroperbenzoic acid is added over 10 minutes to an ice-cooled solution of 14.6 g of 5,8-dihydro-1-naphthol (prepared as described in Org. Syn., Coll. Vol. IV. pg. 887) in 225 ml of ethyl acetate. After 16 hours at ambient temperature the slurry is poured into a cooled, stirred mixture of 300 ml each of ether and 10% sodium bicarbonate. After 15 minutes the organic phase is separated, washed with water, saturated salt solution and dried. Solvent removal gives an oil which is triturated with two 100 ml portions of boiling hexane. The residue is recrystallized from 150 ml of 1:1 hexane-ethyl acetate to give 6.6 g of 5,6,7,8-tetrahydro-6,7-epoxy-1-naphthol, melting point 143.degree.-146.degree. C. Two further recrystallizations of a small sample give the analytical sample melting point 149.5.degree.-151.degree. C.
(b). trans-5,6,7,8-Tetrahydro-1,6,7-naphthalenetriol
A solution of 8.0 g of 5,6,7,8-tetrahydro-6,7-epoxy-1-naphthol in 100 ml of tetrahydrofuran is cooled to 0.degree. C. and 20 ml of water and 0.5 ml of 70% perchloric acid are added. After 4 hours, a further 1.5 ml of acid is added and the solution is stirred for 16 hours at ambient temperature and diluted with 100 ml each of ether, 10% sodium bicarbonate and saturated salt solution. The aqueous layer is separated and washed with 150 ml of 1:1 ether-tetrahydrofuran. The organic phase is washed with saturated salt solution, dried and evaporated to give an oil which solidifies on trituration with chloroform. Recrystallization gives in two crops, 4.85 g of solid which is recrystallized from ethyl acetate to give 3.84 g, melting point 179.5.degree.-181.5.degree. C. Two further recrystallizations of a small sample give the analytical specimen, melting point 183.degree.-184.degree. C.
(c). 2,3-trans-1,2,3,4-Tetrahydro-5-[2,3-(epoxy)-propoxy]-2,3-naphthalenediol
A solution of 3.60 g of trans-5,6,7,8-tetrahydro-1,6,7-naphthalenetriol in 100 ml of methanol is cooled to 0.degree. C. and 1.08 g of sodium methoxide in methanol is added. The solvent is removed in vacuo and the residue heated at 50.degree. C. at 0.05 mm for 1 hour, dissolved in 80 ml of dimethylsulfoxide and stirred overnight under nitrogen with 3.68 g of epichlorohydrin. After 17 hours, the solvent is removed in vacuo, and the residue is dissolved in 250 ml of water and extracted 3 times with 150 ml of ether and 2 times with 150 ml of chloroform. Both organic extracts are washed with excess 5% sodium hydroxide, saturated salt solution and dried. Solvent removal gives a total of 3.25 g of solid which is recrystallized from benzene to give 2.59 g of the title compound, melting point 113.degree.-116.degree. C.
(d). 2,3-trans-1,2,3,4-Tetrahydro-5-[2-hydroxy-3-(isopropylamino)propoxy]-2,3-n aphthalenediol
A solution of 2.5 g of 2,3-trans-1,2,3,4-tetrahydro-5-[2,3-(epoxy)-propoxy]-2,3-naphthalenediol in 15 ml of isopropylamine is heated at 80.degree. C..+-. 5.degree. for 16 hours in a Parr bomb (pressure= 40 lb/in.sup.2). The solution is evaporated in vacuo to give a foam which crystallizes on trituration with ether. Filtration gives 2.96 g which is recrystallized three times from benzene to give 2.06 g of the title compound, melting point 112.degree.-127.degree. C.
(e). 2,3-trans-5-[(3-isopropyl-2-phenyl-5-oxazolidinyl)methoxy]-1,2,3,4-tetrahy dro-2,3-naphthalenediol
Benzaldehyde (0.025 mole) is added to a suspension of 2,3-trans-1,2,3,4-tetrahydro-5-[2-hydroxy-3-(isopropylamino)propoxy]-2,3-n aphthalenediol (0.005 mole) in 50 ml of xylene, and the mixture is stirred at reflux for 48 hours with a Dean-Stark trap in the system. The solvent is removed in vacuo to yield the title compound.
(f). 2,3-trans-5-[(3-isopropyl-2-phenyl-5-oxazolidinyl)methoxy]-1,2,3,4-tetrahy dro-2,3-naphthalenediol, diacetate ester
Acetic anhydride (0.008 mole) is added to a solution of (0.005 mole) in 20 ml of dry pyridine and the solution is stirred for 6 hours at room temperature. The solution is diluted with 4 ml of methanol, stirred for 10 minutes and then evaporated in vacuo to yield the title compound.
(g). 5-[2-hydroxy-3-(isopropylamino)propoxy]-1,2,3,4-tetrahydro-2,3-cis-naphtha lenediol, diacetate ester
Palladium on carbon (0.8 g, 5%) is added to a solution of 2,3-trans-5-[(3-isopropyl-2-phenyl-5-oxazolidinyl)methoxy]-1,2,3,4-tetrahy dro-2,3-naphthalenediol, diacetate ester (0.002 mole) in 50 ml of absolute ethanol and the mixture is placed on a Parr shaker under 54 psi of hydrogen for 23 hours. The mixture is filtered, the catalyst washed with 150 ml of absolute ethanol, and the combined filtrates evaporated in vacuo to give the title compound.
Claims
What is claimed is:
1. A compound having the formula ##STR18## or a pharmaceutically acceptable salt thereof, wherein R.sup.1 is lower alkyl; R.sup.3, R.sup.4, R.sup.5, R.sup.6 and R.sup.7 are the same or different and are hydrogen or lower alkyl; R.sup.8, R.sup.9 and R.sup.10 are the same or different and are hydrogen, lower alkyl, lower alkoxy, or monocyclic cycloalkyl having 3 to 6 carbon atoms; and R.sup.11 is an acyl group of the type ##STR19## wherein n is an integer of from 1 to 11, ##STR20## wherein X is monocyclic aryl, or ##STR21## wherein Z is monocyclic aryl-lower alkyl; wherein lower alkyl and lower alkoxy are groups having 1 to 8 carbon atoms and monocyclic aryl is phenyl, lower alkyl phenyl, di(lower alkyl)-phenyl, halophenyl, nitrophenyl, dinitrophenyl, or trinitrophenyl.
2. A compound in accordance with claim 1 wherein R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9 and R.sup.10 are hydrogen.
3. A compound in accordance with claim 2 wherein R.sup.1 is isopropyl.
4. A compound in accordance with claim 3 wherein R.sup.11 is ##STR22##
5. A compound in accordance with claim 3 wherein R.sup.11 is ##STR23##
6. A compound in accordance with claim 3 wherein R.sup.11 is ##STR24##
Patent Citations (2)
| Patent | Date | Inventor | Cited By |
|---|---|---|---|
| DT2,130,393 | 1971-12-01 | ||
| DT2,258,995 | 1972-12-01 |