US 4,760,052 AGrant
1,6-Dicarba-Vasopressin Compounds
Issue Date:1988-07-26
•17 Claims
Abstract
New compounds which have potent V.sub.2 -vasopressin antagonistic activity are prepared by a 1,6-cyclization using peptide bond formation. The structures of the compounds are characterized by a Pas.sup.1,6 or Tas.sup.1,6 cyclized unit. Also a chiral synthesis of the optically pure Pas intermediates is described.
Metadata
Assignee
- Smithkline Beckman Corporation
Inventors
- James F. Callahan
- William F. Huffman
- Kenneth A. Newlander
- Nelson C. F. Yim
Application Information
Application Number:US 0436585
Filing Date:1987-04-28
Priority Date:1986-01-16
Art Unit:153
Classifications
IPC:
A61K 3734C07K 716
Field of Search:
51453011;807315
Patent Drawings
This patent does not have any drawings.
Description
The following examples are intended to demonstrate the preparation and use of this invention. All temperatures are in degrees Centigrade. Terms and symbols are those common in the chemical and peptide arts.
EXAMPLE 1
Synthesis of Spirocycloalkylene-2-aminoalkanedioic acids
(A) Methyl 1-(5-Pent-1-enyl)cyclohexane carboxylate
A solution of lithium diisopropylamide was prepared by adding 2.7M n-butyl lithium (hexane) (37.0 ml, 100 mmol) to a solution of diisopropylamine (15.0 ml, 109 mmol) in dry tetrahydrofuran (170 ml) at -78.degree. under argon, then stirring the subsequent mixture at -78.degree. for 20 minutes. Methyl cyclohexanecarboxylate (13.0 ml, 91 mmol) was added to the solution and the reaction mixture was stirred for 30 minutes at -78.degree. . 5-Iodopent-1-ene (18 g, 91.8 mmol) was added, the reaction continued at -78.degree. for 10 minutes and the mixture was then slowly brought to room temperature. The reaction mixture was diluted with water, acidified (pH=2) with 3N hydrochloric acid and extracted with ether. The ether extracts were washed with saturated sodium thiosulfate (aqueous), dried over magnesium sulfate and evaporated at reduced pressure to give 16 g of methyl 1-(5-pent-1-enyl)cyclohexanecarboxylate ester.
(B) 1-(O-Tosyl)hydroxymethyl-1-(5-pent-1-ene)cyclohexane
The methyl ester (A) (16 g, 76.0 mmol) was added to a solution of lithium aluminum hydride (4.6 g, 120.9 mmol) in tetrahydrofuran (205 ml) at room temperature and the resulting mixture was heated at reflux for 3 hours. The reaction was cooled to 0.degree. , treated sequentially with water (5 ml), 3N sodium hydroxide solution (5 ml) and water (15 ml) then filtered. The filtrate was dried over magnesium sulfate, filtered and evaporated to give the titled alcohol: .sup.1 HNMR (CDCl.sub.3): 6.17-5.60 (m, 1H), 5.20-4.80 (m, 2H), 3.40 (S, 2H) and 2.43-0.80 (m, 17H).
This alcohol was dissolved in pyridine (89 ml) and treated with p-toluenesulfonyl chloride (27 g, 142.5 mmol) at 0.degree. for 4 hours. The reaction mixture was poured into water and extracted with petroleum ether, petroleum ether:ethyl ether (1:1) and ethyl ether. The combined organic extracts were washed with 0.5N HCl (aqueous), saturated sodium bicarbonate (aqueous) and water, dried over magnesium sulfate, filtered and evaporated to give 30.0 g of 1-(O-tosyl)hydroxymethyl-1-(5-pent-1-ene) cyclohexane: .sup.1 HNMR (CDCl.sub.3): 7.98-7.20 (m, 4H), 6.03-5.53 (m, 1H), 5.13-4.78 (m, 2H), 3.82 (S, 2H), 2.43 (S, 3H) and 2.23-0.73 (m, 16H).
(C) 1 -Cyanomethyl-1-(5 -pent-1-ene)cyclohexane
The tosylate (B) (30 g) was dissolved in dimethylsulfoxide (219 ml) with sodium cyanide (13.6 g, 279 mmol). The resulting mixture was heated at 150.degree. for 18 hours. The reaction mixture was then cooled, poured onto saturated ammonium chloride (aqueous) and extracted with petroleum ether. The organic extracts were dried, filtered and evaporated. Purification of the residue using flash chromatography (silica gel; 15% ethyl acetate/hexane) gave 9.9 g of 1-cyanomethyl-1-(5-pent-1-ene)cyclohexane (57% yield from methyl cyclohexanecarboxy-late): .sup.1 HNMR (CDCl.sub.3): 6.12-5.57 (m, 1H), 5.20-4.87 (m, 2H), 2.30 (S, 2H), 2.23-1.82 (m, 2H) and 1.50 (brS, 14H).
(D) 1-Cyanomethyl-1-(4-butan-1-alyl)cyclohexane.
The nitrile (C) (4.9 g, 25.6 mmol) was dissolved in methanol (80 ml). The resulting solution was cooled to -78.degree. and treated with ozone [from a Welsbach ozone generator] until residual ozone was left in solution (blue color). The crude ozonide was treated with methyl sulfide (20 ml) at -78.degree. and, then, slowly warmed to room temperature. After 18 hours, the solvent was removed under reduced pressure and the residue was purified by flash chromatography (silica gel, 20% ethyl acetate/hexane) to give 3.1 g (63%) of 1-cyanomethyl-1-(4-butan-1alyl)-cyclohexane:
NMR (CDCl.sub.3): 9.80 (brS, 1H), 2.63-2.38 (m, 2H), 2.33 (S, 2H) and 1.47 (brS, 14H).
(E) 2Amino5-[(1-carboxymethyl)cyclohexyl]pentanoic acid
The aldehyde (D) (3.1 g, 16 mmol) was dissolved in 60% aqueous ethanol (30 ml), treated with sodium cyanide (860 mg, 17.6 mmol) and ammonium carbonate (4.0 g, 41.6 mmol). The resulting solution was heated at reflux for 18 hours. Excess carbonate was removed by heating the reaction mixture at 90.degree. for 1 hour without a condenser. The remaining solvent was removed at reduced pressure. The crude product was dissolved in hot ethanol, filtered and evaporated under reduced pressure to give the crude hydantoin: MS: (M+H).sup.+ =264. The unpurified hydantoin was suspended in water with barium hydroxide hexahydrate (12.0 g, 38 mmol) and heated in a sealed bomb at 170.degree. for 96 hours. The reaction mixture was cooled, diluted with water and filtered. The filtrate was passed over a BioRad AG 50W-X8 ion exchange column and the desired product was eluted off the column with 1Nammonium hydroxide (aqueous). Evaporation of the ammonium hydroxide eluent gave 1.1 g of the titled amino acid (E): MS: (M+H).sup.+= 258. This compound is also trivially named 6,6-cyclopentamethylene-2-aminosuberic acid (Pas).
(F) 2-Boc-amino-5-[(1-carboxymethyl)cyclohexyl]pentanoic acid
The amino acid (E) was dissolved in 1N sodium hydroxide solution (45 ml) and tert butanol (45 ml) and the mixture was treated at room temperature with di-tertbutyldicarbonate (980 mg, 4.5 mmol) for 48 hours. The reaction mixture was washed with hexane, acidified with sodium bisulfate and extracted with ethyl acetate. The combined organic extracts were dried, filtered and evaporated to give 1.5 g of the titled compound.
(G) Methyl 2-t-Boc-amino-5-[(1-carbomethoxymethyl)cyclohexyl]pentanoate
The Boc-diacid (F) (1.5 g) was dissolved in methylene chloride and treated with excess ethereal diazomethane at 0.degree. . After quenching the excess diazomethane with acetic acid, the solution was evaporated at reduced pressure. The crude ester was purified by flash chromatography (silica gel, 20% ethyl acetate/hexane) to give 900 mg (56%) of the titled product: .sup.1 HNMR (CDCl.sub.3): 5.23-4.87 (m, 1H), 4.50-4.10 (m, 1H), 3.77 (S, 3H), 3.67 (S, 3H), 2.30 (S, 2H), 1.47 (S, 9H) and 1.42 (brS, 16H).
(H) 2-t-Boc-amino-5-[(1-carbomethoxymethyl)cyclohexyl]pentanoic acid
The Boc diester (G) (1.135 g, 2.94 mmol) was dissolved in dioxane (16 ml) and the solution treated at 5.degree. with 3.2 ml 1N NaOH (aqueous). The reaction mixture was immediately warmed to room temperature and stirred for 4 hours. The reaction mixture was acidified (pH=2) with 3N hydrochloric acid, then evaporated at reduced pressure. The residue was diluted with water and extracted with ethyl acetate. The combined organic extracts were dried, filtered and evaporated. The residue was purified by flash chromatography (silica gel, 5 to 10% methanol/chloroform) to give 836 mg (77%) of titled product. MS: (M+H).sup.+ =372; .sup.1 HNMR (CDCl.sub.3): 8.02 (brS, 1H), 5.28-5.00 (m, 1H), 4.47-4.07 (m, 1H), 3.65 (S, 3H), 2.30 (S, 2H), 1.47 (S, 9H) and 2.00-1.23 (m, 16H).
(I) Benzyl 2-Boc-amino-5-[(1-carbobenzoxymethyl)cyclohexyl]pentanoate
Boc-diacid (F) (1.34 g, 3.75 mmol) in methylene chloride (30 ml) was treated with benzyl alcohol (1.94 ml, 18.75 mmol), dimethylaminopyridine (1.01 g, 8.25 mmol) and N,N'-dicyclohexylcarbodiimide (1.70 g, 8.25 mmol) at room temperature and the mixture was stirred at room temperature for 72 hours. The reaction mixture was then filtered, evaporated at reduced pressure and the residue was dissolved in ethyl acetate which was washed with 3N hydrochloric acid, dried over MgSO.sub.4 and evaporated at reduced pressure. Purification of the residue by flash chromatography (silica gel, 15% ethyl acetate/hexane) gave 1.27 g (63%) of (I): .sup.1 HNMR (CDCl.sub.3): 7.35 (S, 10H), 5.15 (d,J=2.4 Hz, 2H), 5.07 (S, 2H) 5.05-4.70 (m, 1H), 4.50-4.05 (m, 1H), 2.27 (S, 2H), 1.45 (S, 9H) and 2.00-1.03 (m, 16H).
(J) 2-Boc-amino-5-[(1-carbobenzoxymethyl)cyclohexyl]pentanoic acid
The Boc diester (I) (1.27 g, 2.36 mmol) was dissolved in dioxane (15 ml) and treated with 2.6 ml 1N sodium hydroxide solution at room temperature under argon for 4 hours. The reaction mixture was acidified (pH=2) with 3N hydrochloric acid and evaporated at reduced pressure. The residue was dissolved in ethyl acetate, washed with 3N hydrochloric acid, dried over MgS.sub.4 and evaporated at reduced pressure. The residue was purified by flash chromatography (silica gel, 5% methanol/chloroform) to give 1.03 g of the title product: MS: MH.sup.+ =448); .sup.1 HNMR (CDCl.sub.3): 7.33 (S, 5H), 5.07 (S, 2H), 5.20-4.80 (m, 1H), 4.42-4.05 (m, 1H), 2.32 (S, 2H), 1.43 (S, 9H) and 2.08-1.07 (m, 16H).
(K) Methyl 2 -Boc-amino-5-[(1-carboxymethyl)cyclohexyl]pentanoate
The Boc-benzyl ester (J) (4 mmol) is dissolved in methylene chloride and treated with excess ethereal diazomethane at room temperature. The residual diazomethane is quenched with acetic acid and the solution is evaporated at reduced pressure. The crude diester is dissolved in methanol and hydrogenated over 10% palladium-on-carbon to give, after flash chromatography (silica gel), the titled compound.
(L) General
Running the above sequence of reactions with methyl cyclopentanecarboxylate gives 2-amino-5-[(1-carboxymethyl)cyclopentyl]pentanoic acid and 2-t-Boc-amino-5-[(1-carbobenzoxymethyl)cyclopentyl]-pentanoic acid. Using 4-iodobut-1-ene or 6-iodohex-1-ene in place of 5-iodo-pent-1-ene in the first step of the reaction sequence described in detail above gives 2-amino-4-[(1-carboxymethyl)cyclohexyl]butanoic acid, 2-amino-6-[(1-carboxymethyl)cyclohexyl]hexanoic acid as well as their N-Boc and 1-benzyl ester derivatives. One skilled in the art will reoognize the latter two amino acids are the 2-aminospirocyclopentamethylene pimelic and azelaic acids.
EXAMPLE 2
Synthesis of Linear Peptide Intermediates
(A) 2-D,L-Boc-amino-5-(1-carbobenzoxymethyl)cyclo-hexylpentanoylprolyl-(N-Tos) arginyl-BHA resin.
0.5 Mmoles (0.96 g) of BHA resin was swollen in 25 ml of methylene chloride in a 30 ml reaction vessel in a manual peptide synthesizer for 4 hours. It was, then, sequentially coupled with protected arginine and proline as well as 2-D,L-boc-amino-5-(1-carbobenzoxymethyl)cyclohexylpentanoic acid using DCC and HBT or DMAP (4-dimethylaminopyridine) as coupling reagent in mixture of dimethylformamide and methylene chloride as solvent.
The amounts and mole ratio of each reagent used in this experiment are as follows:
After the sequential coupling cycles, the peptide resin (A) was treated with acetic anhydride for 1 hour in order to acetylate any unreacted amino group.
(B) Boc-(O-ethyl-D-tyrosyl)-phenylalanyl-valyl-asparagyl-(OBzl)-6,6-cyclopenta methylene-2-D,L-aminosuberic acid-prolyl-(N-Tos)arginyl-BHA resin.
The tri-unit resin (A) from above was further sequentially coupled in four cycles with Boc-Asn, Boc-Val, Boc-Phe and Boc-D-Tyr(OEt) using DCC/HBT as coupling reagents and CH.sub.2 Cl.sub.2 /DMF as solvent in a manual peptide synthesizer. Each coupling was monitored by a qualitative ninhydrin test in order to test for completion. Repeated coupling is carried out when the test is positive.
The amounts of reagents used are as follows:
The peptide resin was, then, dried in vacuo to give the titled intermediate.
(C) H.sub.2 N-D-Tyr(Et)-Phe-Val-Asn-D,L-Pas-Pro-ArgNH.sub.2
The peptide resin (B) was treated with 20 ml of anhydrous hydrogen fluoride at 0.degree. with 1.5 ml of anisole added as scavanger for 1 hour for the cleavage of the peptide from the resin support and concurrently the deprotection of amino and carboxy groups.
The HF was evaporated under reduced pressure at 0.degree. . The residue was triturated with ether, which was discarded, and was thoroughly extracted with 10 ml.times.3 of dimethylformamide and 10 ml.times.3 of 30% aqueous acetic acid. The extracts were combined and evaporated under reduced pressure to give an oil which was taken up in 5% aqueous acetic acid and lyophilized to give 195 mg of white powder.
This crude linear peptide, H.sub.2 N-D-Tyr(Et)-PheVal-Asn-D,L-Pas-Pro-ArgNH.sub.2 as the acetate salt, was shown to be a mixture of two major components in both HPLC (Ultrasphere ODS column, 50% aqueous acetonitrile with 0.1% TFA) and tlc (silica/n BuOH/ethyl acetate/acetic acid/water 1:1:1:1) with traces of other components.
This crude peptide was purified by counter current distribution (CCD) in BAW (butanol/acetic acid/water) 4:1:5 in 240 transfers. Fractions were checked by tlc and appropriate fractions were pooled, evaporated under reduced pressure and lyophilized from 1% aqueous acetic acid to yield:
Isocratic HPLC (Ultrasphere ODS; 40% aqueous acetonitrile with 0.1% TFA; flow rate equal to 1.5 ml/min) showed two peaks with retention times of 5.09 and 7.80 minutes respectively. Fraction I contained predominately the 5.09 min. isomer (approximately 90%), fraction II contained an aqual amount of both isomers and fraction III contained mostly the 7.80 min. isomer. FAB-Mass spectrum confirmed the presence of the desired peptide (MH.sup.+ =1061; MH.sup.- =1059) in all three fractions.
These results indicate the two peaks are the two desired D- and L-isomers of titled linear peptide intermediate (C).
EXAMPLE 3 ##STR4##
The linear peptide (C) from Example 2 (50 mg) was treated with 1N HCl in glacial acetic acid and, then, evaporated in vacuum to dryness. This was repeated three times. The residue was taken up in dried dimethylformamide and evaporated in vacuo. This was repeated three times. (This process is to convert the acetic acid salt at the amino and guanidino groups to the corresponding stronger hydrochloric acid salt in situ and, thus, eliminate the side reaction of acetylation of the .alpha.-amino group of the D-Tyr by the liberation of the acetic acid. This conversion can also be accomplished by ion exchange column chromatography with some loss of material.)
The treated residue was dissolved in 7.5 ml of dried dimethylformamide, then 12.5 ul of triethylamine was added with stirring, followed by addition of 20 .mu.l of diphenylphosphoryl azide (DPPA). The resulted mixture was stirred under an argon atmosphere at room temperature overnight. The completion of the cyclization is monitored by isocratic HPLC or by tlc.
The reaction mixture was evaporated to dryness and redissolved in 30% acetic acid. The salt was removed by a G-15 Sephadex gel filtration column. The product was further purified and separated into D- and L-isomers by preparative HPLC in C.sub.18 column using 45% acetonitrile in water with 0.1% trifluoroacetic acid as mobile phase to give 8.5 mg of compound C of Table 1 above containing the L-Pas and 5 mg of compound D containing the D-Pas. The chirality of the Pas was determined by comparing the derivativized hydrosylate of compound C and D to authentic L-Pas by chiral GC analysis.
EXAMPLE 4 ##STR5##
The linear, protected Boc-D-Tyr(Et)-Phe-Val-Asn-Pas(OBzl)Pro-Arg(Tos)-BHA was prepared in the same manner as Example 2 except optically pure Boc-L-Pas(OBzl) was used in place of Boc-D,L-Pas(OBzl). The peptide was cleaved from the resin with removal of protecting groups by treatment with liquid HF (10 ml) in the presence of anisole (1 ml) at 0.degree. for 50 minutes. After removal of the HF under vacuum, the resin was washed with ether and air dried. The resin was then extracted with 10% HOAc (120 ml), 1% HOAc (120 ml) and water (120 ml). The aqueous extracts were combined, diluted with water and lyophilized to yield 213 mg crude linear peptide. 100 mg crude linear peptide was purified by gel filtration on G-15 with 1% HOAc to yield 62 mg purified linear peptide.
62 mg purified linear peptide (58.4 .mu.mol) was dissolved in 5 ml HOAc and 5 ml 1.7 M HCl/HOAc and evaporated to dryness. The residue was dissolved in DMF and evaporated to dryness 3 times. The residue was then dissolved in 10 ml DMF and 12.8 .mu.1 diphenylphosphoryl azide (1.1 eq) followed by 17.8 .mu.1 triethylamine (2.2 eq) were added. The reaction mixture was kept at 4.degree. for 3 days. An additional 6.4 .mu.1 diphenylphosphoryl azide (0.5 eq) and 8.9 .mu.1 triethylamine (1.0 eq) was then added and the reaction mixture kept at 4.degree. overnight. The reaction mixture was then evaporated to dryness and the resulting glass was triturated with ether. The crude cyclic peptide was collected by filtration and air-dried, yielding 75 mg. The crude cyclic peptide was purified by prep hplc (Hamilton PRP-1,45% acetonitrile/water/0.1% TFA). The appropriate fraction were pooled, evaporated to dryness and lyophilized from 1 % HOAc to yield 35.3 mg purified cyclic peptide. FAB-MS m/z 1043.7 (MH+),HPLC k' =2.92 (45% acetonitrile/water/0.1% TFA). This compound coeluted with compound C in Example 3.
EXAMPLE 5
Procedure for Terminal Coupling ##STR6##
The protected peptide intermediate resin, i.e., Boc-D-Tyr(Et)-Phe-Val-Asn-D,L-Pas-OCH.sub.2 -C.sub.6 H.sub.4 -Resin-OCH.sub.3 is synthesized manually on a shaker. Boc-D,L-Pas(OCH.sub.2 C.sub.6 H.sub.4 -Resin)OCH.sub.3 is prepared from Boc-D,L-Pas-OCH.sub.3 by direct coupling to hydroxymethyl resin with DMAP/DCC in CH.sub.2 Cl.sub.2 with substitution of 0.50 meg./g. The protected peptide-resin ntermediate is synthesized stepwise by deprotecting the Boc-group using 1:1 TFA:CH.sub.2 Cl.sub.2 and coupling sequentially with the appropriate Boc-amino acids using DCC/HBT as activating and catalyzing reagents on 1.0 mmol scale to give the resin coupled intermediate. The linear peptide is obtained by cleavage from the resin using HF 20 ml in the presence of 2.0 ml of anisole at -10.degree. for 60 min. After evaporation in vacuo to dryness, the residue is washed with anhydrous diethyl ether and is extracted with TFA, degassed dimethylformamide, and acetic acid. The extracts were combined, evaporated in vacuo to dryness, taken up in acetic acid and lyophilized to give the crude linear peptide. Cyclization of this peptide, NH.sub.2 -D-Tyr(Et)-Phe-Val-Asn-D,L-Pas-OCH.sub.3 (150 mg) with DPPA (45.mu.1) and Na.sub.2 CO.sub.3 (45 mg) in DMF (120 ml) at room temperature overnight with yields after evaporation and prep. HPLC, 80 mg cyclic peptide (diasteromers not separated). FAB-MS:m/z 805 (MH+)1 m/z 803 (M-H).sup.- ; hplc:RT=26.7, 27.2 min (Ultrasphere C-18, mobile phase A: 0.1% TFA/H.sub.2 O, B:0.1% TFA/CH.sub.3 CN; linear gradient 70-40% A, 30 min, 40% A, 10 min). ##STR7##
Repeating the same synthesis as in (A) using Boc-L-Pas-OCH.sub.3 in place of Boc-D,L-Pas-OCH.sub.3 yields after purification cyclo [D-Tyr-(Et)-Phe-Val-Asn-L-Pas]OCH.sub.3. ##STR8##
A suspension of 0.1 mmol of the methyl ester (A) above in 1:1 dioxane -10% K.sub.2 CO.sub.3 (aqueous) is stirred at room temperature for 8 hours. The reaction mixture is diluted with water and acidified to pH=4 with glacial acetic acid. The resulted solution is evaporated in vacuo and the residue purified by gel chromatography.
(D) D-Tyr(Et)-Phe-Val-Asn-Pas-NHNH.sub.2
The methyl ether (A) above (100 mg) is treated with anhydrous hydrazine in methanol at room temperature to give after evaporation the titled compound, the hydrazide.
(E) Condensation
The 6 Pas acid (20 mg) from (C) above is reacted with one equivalent of N-.epsilon.-BocLys Arg(NH.sub.2).2HCl in the presence of DCC, HBT and one equivalent of triethylamine in dimethylformamide followed by treatment with trifluoro acetic acid to produce cyclo[D Tyr(Et) Phe Val Asn Pas]-Lys Arg-NH.sub.2.
Similarly the corresponding 7-Arg acid cyclized peptide and the 7-Pro cyclized peptide acid congeners are made from reacting the acylazide derived from the hydrazide (D) using arginine or proline. Either acid compound is isolated as the potassium salt if desired. One equivalent of Arg NH.sub.2.2HCl is coupled with the corresponding 7-D-Pro acid made as described using DCC/HBT to give the respective 7-D-Pro-Arg-NH.sub.2 peptide.
EXAMPLE 6 ##STR9##
The linear, protected peptide Boc-D-Tyr(Et)-Phe-Val-Asn-D,L-Pas(OBzl)-Arg(Tos)-D-Arg(Tos)-BHA was prepared in the usual manner. The linear peptide was cleaved from the resin with removal or protecting groups by treatment with liquid HF (10 ml) in the presence of anisole (1 ml) at 0.degree. for 50 minutes. After removal of the HF under vacuum, the resin was washed with ether and air-dried. The resin was then extracted with 60 ml 10% HOAc, 60 ml 1% HOAc and 60 ml water. The extracts were combined, diluted with water and lyophilized to yield 324 mg crude linear peptide. 275 mg linear peptide was purified by countercurrent distribution (nBuOH/HOAc/water 4:1:5) to yield 166.7 mg purified linear peptide.
66.7 mg linear peptide (59.6 .mu.mol) was dissolved in 5 ml HOAc and 5 ml 1.8 M HCl/HOAc. The solution was evaporated to dryness and the residue dissolved in DMF and evaporated to dryness 3 times. The residue was then dissolved in 10 ml DMF and 12.9 .mu.l diphenylphosphoryl azide (1.1 eq) was added followed by 18 .mu.l triethylamine (2.2 eq). The reaction mixture was kept at 4.degree. for 3 days. An additional 6.5 .mu.l diphenylphosphoryl azide (0.5 eq) and 9 .mu.l triethylamine (1.0 eq) was added and the reaction kept at 4.degree. overnight. The reaction mixture was then evaporated to dryness and the residue triturated with ether to yield the crude cyclic peptide as a slightly hygroscopic solid which was collected by filtration. The peptide was dissolved in 5 ml methanol and purified by prep HPLC on Hamilton PRP-1 (9 mm.times.30 cm) using 33% acetonitrile/water/0.1% TFA. The appropriate fractions were pooled, evaporated to dryness and lyophilized from 1% HOAc to yield 45.0 mg purified cyclic peptide. FAB-MS m/z 1102.8 (MH+), HPLC k'=5.0 (Hamilton PRP-1, mobile phase A 0.1% TFA, B 0.1% TFA/acetonitrile, linear gradient 20-50% B, 15 minutes, 50% B, 5 minutes).
EXAMPLE 7 ##STR10##
The linear, protected peptide Boc-D-Tyr(Et)-Phe-Val-Asn-Pas(OBzl)-Arg(Tos)-D-Arg(Tos)-BHA was prepared in the usual manner. 2.0 g of the peptide resin was cleaved with removal of protecting groups by treatment with liquid HF (40 ml) in the presence of dimethylsulfide (2.0 ml) at 0.degree. C. for 60 minutes. After removal of the HF under vacuum, the resin was washed with ether, extracted with 50% acetic acid, 20% acetic acid and water. The extracts were combined and lyophilized to yield 1.07 g crude linear peptide.
1.07 g of the crude, linear peptide (956 .mu.mol) was purified via HPLC on Vydac ODS using 25% acetonitrile/0.1 M triethylammonium phosphate. The purified peptide was then adsorbed onto an SM-2 column, washed with 0.05M HCl, and eluted from the column with 90% MeOH to yield 358 mg of linear peptide as the hydrochloride salt.
125 mg of linear peptide (108 .mu.mol) was then dissolved in 21 ml DMF. 36.2 .mu.l of triethylamine (259 .mu.mol) was added followed by 28.0 .mu.l of diphenyl phosphoryl azide (130 .mu.l). The solution was kept at 4.degree. for three days. The reaction mixture was then evaporated to dryness and the residue triturated with ether. The crude cyclic peptide was then purified via HPLC (Hamilton PRP-1, 33% acetonitrile/water/0.1% TFA) to yield, after lyophilization from 1 M HOAc, 90 mg of cyclic peptide. FAB-MS m/z 1102 (MH+), HPLC k'=4.5 (IBM ODS, mobile phase A=0.1 M triethylammonium phosphate, B=acetonitrile, linear gradient 30 40% B, 10 minutes, 40-60% B, 20 minutes).
EXAMPLE 8 ##STR11##
The linear, protected peptide Boc-D-Tyr(Et)-Phe-Val-Asn-D-Pas(OBzl)-Arg(Tos)-D-Arg(Tos)-BHA was prepared in the usual manner. The linear peptide was cleaved from the resin with removal of protecting groups by treatment with liquid HF (10 ml) in the presence of anisole (1 ml) at 0.degree. for 50 minutes. After removal of the HF under vacuum, the resin was washed with ether and air-dried. The resin was then extracted with 60 ml 10% HOAc, 60 ml 1% HOAc and 60 ml water. The extracts were combined, diluted with water and lyophilized to yield 335 mg crude linear peptide. The crude linear peptide was purified by countercurrent distribution (nBuOH/HOAc/water 4:1:5) to yield 287.9 mg partially purified linear peptide. 100 mg of the partially purified peptide was further purified by gel filtration on G-15 using 10% HOAc to yield 38 mg purified linear peptide.
38 mg linear peptide (33.9 .mu.mol) was dissolved in 5 ml HOAc and 5 ml 1.8 M HCl/HOAc. The solution was evaporated to dryness and the residue dissolved in DMF and evaporated to dryness 3 times. The residue was then dissolved in 6 ml DMF and 7.4 .mu.l diphenylphosphoryl azide (1.1 eq) was added followed by 10.4 .mu.l triethylamine (2.2 eq). The reaction mixture was kept at 4.degree. for 3 days. An additional 3.7 .mu.l diphenylphosphoryl azide (0.5 eq) and 5.2 .mu.l triethylamine (1.0 eq) was added and the reaction kept at 4.degree. overnight. The reaction mixture was then evaporated to dryness and the residue triturated with ether to yield the crude cyclic peptide as a slightly hydroscopic solid which was collected by filtration. The peptide was dissolved in 2 ml methanol and purified by prep HPLC on Hamilton PRP-1 (9 mm.times.30 cm) using 35% acetonitrile/water/0.1% TFA. The appropriate fractions were pooled, evaporated to dryness and lyophilized from 1% HOAc to yield 25.6 mg purified cyclic peptide. HPLC k'=5.0 (Hamilton PRP-1, mobile phase A 0.1% TFA, B 0.1% TFA/acetonitriIe, linear gradient 20-50% B, 15 minutes, 50% B, 5 minutes).
EXAMPLE 9 ##STR12##
The linear, protected peptide Boc-D-Tyr(Et)-Phe-Val-Asn-Pas(OBzl)-Arg(Tos)-BHA was prepared in the usual manner. The linear peptide was cleaved from the resin with removal of protecting groups by treatment with liquid HF(10 ml) in the presence of anisole (1 ml) at 0.degree. for 50 minutes. After removal of the HF under vacuum, the resin was washed with ether and air-dried. The resin was then extracted with 30 ml 50% HOAc, 60 ml 10% HOAc, 60 ml 1% HOAc and 60 ml water. The extracts were combined, diluted with water and lyophilized to yield 564 mg crude linear peptide. The resin was re extracted with DMF, which was evaporated to dryness and the residue lyophilized from 10% HOAc to yield an additional 113 mg crude linear peptide.
1mg crude, linear peptide (103 7 .mu.mol) was dissolved in 10 ml HOAc and 2 ml DMF. To this was added 10 ml of 1.8 M HCl/HOAc. The solution was evaporated to dryness and the residue dissolved in DMF and evaporated to dryness 3 times. The residue was then dissolved in 20 ml DMF and 22.5 .mu.l diphenylphosphoryl azide (1.1 eq) was added followed by 31.7 .mu.l triethylamine (2.2 eq). The solution was kept at 4.degree. for three days. An additional 10 .mu.l diphenylphosphoryl azide (0.5 eq) and 7.2 .mu.l triethylamine (0.5 eq) was added and the reaction kept at 4.degree. overnight. The reaction mixture was then evaporated to dryness and the residue was triturated with ether to yield a yellow, slightly hygroscopic solid which was collected by filtration. The crude cyclic peptide was purified by countercurrent distribution (nBuOH/EtOAc/HOAc/water 2:2:1:5) followed by gel filtration (G-15, 10% HOAc) to yield 32.6 mg purified cyclic peptide. FAB-MS m/z 946 (MH+), HPLC k'=4.95 (Hamilton PRP-1, mobile phas A=0.1% TFA, B=0.1% TFA/acetonitrile, linear gradient 20-50% B, 15 minutes, 50% B 5 minutes.
EXAMPLE 10 ##STR13##
The protected peptide intermediate resin, D-Tyr(Et)-Phe-Val-Asn-Pas(OBzl)-Arg(Tos)-Arg(Tos)-BHA is synthesized on 1.0 mmol of benzhydrylamine resin as above. The HF cleavage and cyclization with DPPA are performed as described to give the partially purified crude peptide.
EXAMPLE 11 ##STR14##
The protected peptide intermediate resin, Boc-D-Tyr(Et)-Phe-Val-Asn-Pas(OBzl)-N-MeArg(Tos)-Arg(Tos)-BH Ais prepared by the solid phase method on benzhydrylamine resin on a shaker using 0.5 mmol of BHA resin is used. All amino acids are protected as tert.-butyloxycarbonyl on the nitrogen and coupled sequentially using DCC/HBT, while the Pas(Bzl) is coupled using DMAP. The peptide is cleaved from the resin with deprotection of the side-chain protecting groups using anhydrous HF (20 ml) and anisole (2 ml) at 0.degree. for 60 minutes. The peptide is extracted from the resin with aqueous HOAc/DMF. After evaporation in vacuo to dryness, the peptide residue is washed with anhydrous diethyl ether and cyclized as described with DPPA to give the titled compound.
EXAMPLE 12 ##STR15##
To a solution of the Pro.sup.7 -acid, prepared as described in Example 5, (0.033 mmol) and mono Boc-1,5-diaminopentane (20.2 mg, 0.0996 mmol) in dimethylformamide (400 .mu.l), dicyclohexylcarbodiimide (10.3 mg, 0.05 mmol) and 1-hydroxybenzotriazole hydrate (13.4 mg, 0.1 mmol) are added. The reaction mixture is stirred at room temperature for 19 hours. The dimethylformamide is then removed under vacuum. The residue is treated with trifluoroacetic acid at 0.degree. for 2 hours. After this time, the trifluoroacetic acid is removed under vacuum and the residue in 1% acetic acid is passed over a BioRex 70 (H.sup.+) ion exchange column. The basic products are washed off the ion exchange column with pyridine buffer (H.sub.2 /pyridine/HOAc, 66:30:4) and evaporated. Final purification by preparative HPLC (5u Ultrasphere ODS) gives the title compound as the base or the acetate salt.
EXAMPLE 13
(A) Boc-D-Tyr(Et)-Phe(4'-Et)-Val-Asn-Pas(Bzl)-Pro-Arg-(Tos)-Gly-BHA-resin.
Boc-Val-Asn-Pas(Bzl)-Pro-Arg(Tos)-Gly-BHA-resin (3 mmol) is prepared as described above. Further coupling sequentially 1 mmole of this peptide resin with Boc-Phe-(4'-Et) and Boc-D-Tyr(Et) using 3 mmoles of amino acid and 3 mmoles of DCC and 6 mmoles of 1-hydroxybenzotriazole as catalyst. The final peptide resin is washed with methylene chloride and vacuum dried to give the titled product. ##STR16##
1.55 Grams of Boc-D-Tyr(Et)-Phe(4'-Et)-Val-Asn-Pas(Bzl)-Pro-Arg(Tos)-Gly-BHA-resin from A is treated with hydrogen fluoride and subsequent cyclization with an excess of DPPA as described above to give the titled compound.
EXAMPLE 14
Using the methods of synthesis described in detail above, the following specific compounds are produced.
A. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine]vasopressin;
B. [1,6-(6,6-cyclopentamethylene-2-aminosuberc acid)-2-D-valine-3-(O-ethyltyrosine)-4-valine-8-argomome]vasopressin.
C. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid)-2-D-cyclohexylalanine-7-desproline-8-arginine]vasopressin.
D. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid)-2-methionine-4-alanine-7-D-(N-methylalanine)-8-arginine-9-desglycine ]vasopressin.
E. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine-9-desglycine ]vasopressin.
F. [1,6-(6,6-cyclotetramethylene-2-aminosuberic acid)-2-norleucine-3-isoleucine-4-cyclohexylglycine-8-arginine]vasopressin
G. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid)-2-(O-methyltyrosine)-4-valine-7-desproline-8,9-bishomoarginine]vasop ressin.
H. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine]vasopressin;
I. [1,6-(6,6-cyclopentamethylene-2-aminosuberic acid)-2-L-tyrosine)-4-valine-8,9-bisarginine]vasopressin.
EXAMPLE 15
Using the methods of synthesis described in detail above, the following specific compounds are produced.
A. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine]vasopressin.
B. [1,6-(6,6-cyclopentamethylene-2-amino-L-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine]vasopressin.
C. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine]vasopressin
D. [1,6-(6,6-cyclopentamethylene-2-amino-L-subseric acid)-2-D-tyrosine-4-valine-7-arginine-8-D-arginine-9-desglycine]vasopress in.
E. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-D-tyrosine-4-valine-7-arginine-8-D-arginine-9-desglycine]vasopress in.
F. [1,6-(6,6-cyclopentamethyline-2-amino-L-suberic acid)-2-D-phenylalanine-4-valine-7-arginine-8-D-arginine-9-desglycine]vaso pressin.
G. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-D-phenylalanine-4-valine-7-arginine-8-D-arginine-9--desglycine]vas opressin.
H. [1,6-(6,6-cyclopentamethylene2-amino-L-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-D-arginine-8-D-arginine-9-desglyci ne]vasopressin.
I. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-D-arginine-8-D-arginine-9-desglyci ne]vasopressin.
J. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-N-methylarginine-8-arginine-9-desg lycine]vasopressin.
K. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-(1-amino-4-quanidinob utane)-9-desglycinamide]vasopressin.
L. [1,6-(cyclopentamethylene-2-amino-D-suberic acid)- 2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine9-desglycine]vasopr essin.
M. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9-diaminoethane]vasopress in.
N. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine-9-(1-amino-4 -guanidinobutane)]vasopressin.
O. [1,6-(6,6-cyclopentamethylene-2-amino-L-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-arginine-8-glycine-9-arginine]vaso pressin.
P. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-arginine-8-glycine-9-arginine]vaso pressin.
Q. [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-glutamine-9-arginine]vasopressin.
EXAMPLE 16
Parenteral Dosage Unit Compositions
A preparation which contains 0.1 mg of a peptide of Example 3 as a sterile dry powder for parenteral injection is prepared as follows: 0.5 mg of peptide is dissolved in 1 ml of an aqueous solution of 20 mg of mannitol. The solution is filtered under sterile conditions into a 2 ml ampoule and lyophilized. The reconstituted solution is administered to a patient in need of vasopressin V.sub.2 antagonist treatment as necessary, from 1-5 times daily by injection, or in an equivalent continuous i.v. drip injection.
Nasal Dosage Unit Compositions
2.5 Mg of a finely ground peptide of this invention, such as a product of Example 3, is suspended in a mixture of 75 mg of benzyl alcohol and 1.395 g of a suspending agent such as a commercial mixture of semi-synthetic glycerides of higher fatty acids. The suspension is placed in an aerosol 10 ml container which is closed with a metering valve and charged with aerosol propellants. The contents comprise 100 unit doses which are administered intranasally to a subject in need of aquaretic therapy from 1-6 times a day.
EXAMPLE 17
Synthesis of Optically Pure Formula III Compounds
(A) Synthesis of optically pure benzyl 2-L-Boc-amino-5-[(1-carbobenzoxymethyl)cyclohexylpentanoate
(1) 1,1-Cyclohexanediacetic Anhydride
Acetyl chloride (35 ml, 492 mmol) was added to 1,1-cyclohexanediacetic acid (25 g, 125 mmol) in a round bottom flask and the suspension was heated for 3 hrs. at 0.degree. C. using an oil bath. After about 15 min. the suspension became clear. The reaction was attached to a short path condenser and was heated to 100.degree. C. under vacuum to remove volatile by products. .sup.1 HNMR indicated no starting diacid and GC indicated >99% purity. Upon cooling to room temperature the anhydride solidified. .sup.1 H-NMR (CDCl.sub.3): .delta.62.65(s,4H); 1.45(m,10H).
(2) 1,1-Cyclohexanediacetic Acid Mono-benzyl ester
Toluene (25 ml), benzyl alcohol (14.2 m1,137 mmol) and pyridine (10.1 ml, 125 mmol) were added to the 1,1-cyclohexanediacetic anhydride from above and the resulting solution was stirred at 100.degree. C. overnight. The reaction was taken into ethyl acetate, washed with 1N HCl(aqueous) and saturated NaCl solution (aqueous), dried over MgSO.sub.4, filtered and then evaporated to give a thick oil (37.99 g). Gas chromatography indicated 92.2% purity with the major impurity being benzyl alcohol. .sup.1 H-NMR (CDCl.sub.3): .delta.11.0(s,1H); 7.25(s,5H); 5.0(s,2H); 2.5(s,2H); 1.4(br s,10H).
(3) Benzyl 2-L-Boc amino-5-[(1-carbobenzoxymethyl)cyclohexyl]pentanoate
Sodium (0.15 g) was added to a large metal beaker containing methanol (200 ml) followed by pyridine (80 ml), 1,1-cyclohexanediacetic acid monobenzyl ester (35 g) and N-.alpha.-Boc-L-Glu-.alpha.-benzyl ester (25 g, 74 mmol) dissolved in methanol (40 ml). The solution was electrolized with vigorous mechanical stirring at 100 volts and 2.5 amps between two platinum plates (25.times.50 mm) spaced 2 mm apart. The temperature of the reaction was kept between 20.degree.-25.degree. C. by the aid of an isopropanol/dry ice bath. After 9 hr, TLC indicated most of the starting Boc amino acid was reacted. The reaction was evaporated to give a brown oil which was taken into 1:1 ethyl acetate: n-hexane. The precipitate was filtered off and the filtate was washed two times with dilute HCl (aqueous), two times with 1N Na.sub.2 CO.sub.3 (aqueous), once with sat.NaCl (aqueous), dried over MgSO.sub.4, filtered and evaporated to give an oil. The majority of the impurities were removed by flash chromatography (silica gel 5-10% ethyl acetate:n-hexane). Final purification was achieved using a 3.0.times.100 cm silica gel column eluted with 7% ethyl acetate:n-hexane. A pure fraction contained 7.17 g, 18% of the desired product. This material was identical to the authentic D,L material(I) except that it was optically active. [.alpha.].sub.D =-14.7 c=0.1025 in methanol.
(B) 2-L-Boc-amino-4-[(1-carbobenzoxymethylcyclohexyl]butanoic acid
(1) Benzyl 2-L-Boc-amino-4-[(1-carbobenzoxymethyl)cyclohexyl])butanoate.
Sodium (0.15 g) was added to large metal beaker containing methanol (200 ml) followed by pyridine (80 ml), 1,1-cyclohexanediacetic acid monobenzyl ester (35 g) and N-.alpha.-Boc-L-Asp-.alpha.-benzyl ester (25 g, 77 mmol) dissolved in methanol(40 ml). The solution was electrolized with vigorous mechanical stirring at 100 volts and 2.5 amps between two platinum plates (25.times.50 mm) spaced 2 mm apart. The temperature of the reaction was kept between 20.degree.-25.degree. C. by the aid of an isopropanol/dry ice bath. After 9 hr, TLC indicated most of the starting Boc amino acid was reacted. The reaction was evaporated to give a brown oil which was taken into 1:1 ethyl acetate:n-hexane. The precipitate was filtered off and the filtate was washed two times with dilute HCl (aqueous), two times with 1N Na.sub.2 CO.sub.3 (aqueous), once with sat.NaCl (aqueous), dried over MgSO.sub.4, filtered and evaporated to give an oil. The majority of the impurities were removed by flash chromatography (silica gel, 5-10% ethyl acetate:n-hexane). Final purification was achieved using a 3.0.times.100 cm silica gel column eluted with 7% ethyl acetate:n hexane. A pure fraction containing 6.03 g, 15% of the desired product. .sup.1 H-NMR (CDCl.sub.3): .delta.7.35(s,10H; 5.3-5.0(m,3H); 5.1(s,2H); 4.3(br m,1H); 2.3(s,2H); 1.9-1.0(m,14H); 1.45(s,9H).
(2) 2-L-Boc-amino-4-[(1-carbobenzoxymethyl) cyclohexyl]butanoic acid.
NaOH (aqueous) (1N, 16 ml) was slowly added to benzyl 2-L-Boc-amino-4-(1-carbobenzyoxymethyl)cyclohexyl]-butanoate (6.5 g, 12 mmol) in dioxane (32 ml) with stirring at room temperature. After stirring overnight the reaction was taken up in water acidified with 1N HCl then extracted two times with ethyl acetate. The ethyl acetate phases were combined, washed with sat.NaCl (aqueous), dried over MgSO.sub.4, filtered, and evaporated to give an ozil. The product was purified on a silica gel column (3.times.100 cm) eluted with chloroform, methanol, acetic acid (99:1:0.1). A pure fraction was obtained weighing 3.03 g, 56%. .sup.1 H NMR (CDCl.sub.3): .delta.7.05(s,5H; 5.1(br d,1H); 4.9(s,2H); 4.1(br m,1H); 2.2(d,2H); 2.0 1.1(m,14H); 1.5(s,9H) Mass spectrum (M=H).sup. +=434.
(C) 2-L-Boc-amino-6-[(1-carbobenzoxymethyl)cyclohexyl]hexanoic acid
(1) Synthesis of 1-carbobenzoxymethyl-1-carboxyethylcyclohexane.
Oxalyl chloride (40 ml) was added to 1,1-cyclohexanediacetic acid monobenzylester (50 g, 172 mmol) in toluene (200 ml) with stirring at room temperature (vigorous gas evolution). After two hours the solution was evaporated to an oil then re evaporated two times with toluene. Drying under vacuum left the acid chloride (54 g, quantitative) as a slightly yellowish oil. .sup.1 H-NMR (CDCl.sub.3): .delta.7.0(s,5H); 4.9(s,2H); 3.0(s,2H); 2.4(s,2H); 1.35(br s,10H).
The acid chloride above (13.5 g) in ethyl ether (25 ml) was added dropwise to diazomethane (from 34.5 g Diazald.RTM.) in ethyl ether (350 ml) with stirring in a ice bath. Gas evolution could be seen. After stirring for three hours the excess diazomethane was destroyed by the slow addition of acetic acid (2.5 ml) and the reaction evaporated to dryness. The above reaction was repeated four times to give, after flash column purification (silica gel eluted with 7.5% ethyl acetate in n hexane), the diazomethylketone. (45.5 g, 84%) .sup.1 H-NMR (CDCl.sub.3) .delta.7.0(s,5H); 5.1(s,1H); 4.9(s,2H); 2.45(s,2H); 2.35(s,2H); 1.4(br s,10H).
To the diazomethylketone above (45.5 g) in methanol was added dropwise silver benzoate (3.1 g) in triethylamine (385 ml) with stirring at 0.degree. C. The reaction was shielded from light with aluminum foil and stirred for three hours at room temperature. After de colorizing with charcoal the reaction was filtered then evaporated to a brown oil. The oil was taken up in ethyl acetate and washed with 1N HCl, saturated NaCl (aqueous), dried over MgSO.sub.4, filtered then evaporated. The crude product was flashed chromatographed on silica gel eluting with 2.5% ethyl acetate in n hexane to give 1-carbobenzoxymethyl-1-carbomethoxyethylcyclohexane. (40.4 g, 74%) .sup.1 H-NMR. (CDCl.sub.3): .delta.7.0(s,5H); 4.9(s,2H); 3.45(s,3H); 2.35-2.1(m,2H); 2.2(s,2H); 1.8-1.55(m,2H); 1 35(br s,10H).
To the above 1-carbobenzoxymethyl-1-carbomethoxyethylcyclohexane (40.4 g) in dioxane (300 ml) was added 1N NaOH (150 ml) dropwise over 2 hours with stirring at room temperature. After 6 hours the reaction was neutralized with 1N HCl then the dioxane was evaporated. The cloudy solution was diluted with water, acidified with 1N HCl, then extracted two times with ethyl acetate, washed with saturated NaCl (aqueous), dried with MgSO.sub.4, filtered and then concentrated to an oil. By .sup.1 H-NMR no mono methyl ester could be seen in the crude reaction mixture, the major by-product being the di acid. The product was purified by flash chromatography (silica gel, eluted with CHCl.sub.3, MeOH,HOAc 99:1:0.1) then distilled free of the residual benzyl alcohol to give 1-carbobenzoxymethyl-1-carboxyethylcyclohexane. (29.6 g, 76%) .sup.1 H-NMR. (CDCl.sub.3) .delta.7.05(s,5H); 4.9(s,2H); 2.35-2.1(m,2H); 2.2(s,2H); 1.85-1.55(m,2H); 1.35(br s,10H).
(2) Benzyl 2-L-Boc-amino-6-(1-carbobenzoxymethyl)cyclohexylhexanoate.
Sodium (0.15 g) was added to a large metal beaker containing methanol (200 ml) followed by pyridine (80 ml), 1-carbobenzoxymethyl-1-carboxyethylcyclohexane (25 g) and N-.alpha.-Boc-L-Glu-.alpha.-benzyl ester (25 g, 74 mmol) dissolved in methanol (40 ml). The solution was electrolized with vigorous mechanical stirring at 100 volts and 2.5 amps between two platinum plates (25.times.50 mm) spaced 2 mm apart. The temperature of the reaction was kept between 20.degree.-25.degree. C. by the aid of an isopropanol/dry ice bath. After 9 hr, TLC indicated most of the starting Boc amino acid was reacted. The reaction was evaporated to give a brown oil which was taken into 1:1 ethyl acetate:n-hexane. The precipitate was filtered off and the filtrate was washed two times with dilute HCl (aqueous), two times with 1N Na.sub.2 CO.sub.3 (aqueous), once with saturated NaCl (aqueous), dried over MgSO.sub.4, filtered and evaporated to give an oil. The majority of the impurities were removed by flash chromatography (silica gel, 5-10% ethyl acetate:n-hexane). Final purification was achieved using a 3.0.times.100 cm silica gel column eluted with 7% ethyl acetate:n-hexane. A pure fraction contained 7.8 g, 19% of the desired product. .sup.1 H-NMR (CDCl.sub.3): .delta.7.05 (s,10H); 5.0 (d,2H); 4.9 (s,2H); 4.1 (m,1H); 2.2 (s,2H); 1.9-1.0 (m,18H); 1.4 (s,9H).
(3) 2-L-Boc-amino-6-[(1-carbobenzoxymethyl)cyclohexyl]hexanoic acid.
1N NaOH (aqueous) (18 ml) was slowly added to benzyl-2-L Boc-amino-4-(1-carbobenzyoxymethyl)cyclohexylhexanoate (7.6 g, 13.8 mmol) in dioxane (32 ml) with stirring at room temperature. After stirring overnight the reaction was taken up in water acidified with 1N HCl then extracted two times with ethyl acetate. The ethyl acetate phases were combined, washed with saturated NaCl (aqueous), dried over MgSO.sub.4, filtered, and evaporated to given an oil. The product was purified on a silica gel column (3.times.100 cm) eluted with chloroform, methanol, acetic acid (99:1:0.1) to give pure fraction 3.36 g, 53%.
.sup.1 H-NMR (CDCl.sub.3): .delta.7.05 (s, 5H); 4.95 (br s,1H); 4.9 (s,2H); 4.1 (br s,1H) 2.2 (S, 2H); 1.9-1.0 (m, 18H); 1.4 (S, 9H); Mass spectrum (M+H).sup.+ =462.
(D) General
Running the reaction sequence (A) starting with 1,1-cyclopentane diacetic acid gives benzyl 2-L-Boc-amino-5-[(1-carbobenzoxymethyl)cyclopentyl]pentanoate. Running the reaction sequences A, starting with N-.alpha.-Boc-D-Glu-.alpha.-benzyl ester, N-.alpha.-Boc-D-Asp-.alpha.-benzyl ester or N-.alpha.-Boc-D-Glu--.alpha.-benzyl ester gives benzyl 2-D-Boc-amino-5-[(1-carbobenzoxy-methyl)cyclohexyl]pentanoate, 2-D Boc-amino-4-[(1-carbobenzoxymethyl)-cyclohexyl]butanoic acid or 2-D-Boc-amino-6-[(1-carbobenzoxymethyl)cyclohexyl]hexanoic acid respectively.
Claims
What is claimed is:
1. A chemical compound having the formula: ##STR17## in which: n is 0 or 1; P is a single bond or a D or L isomer of Pro, Pro, Ala, MeAla, Arg, Lys, iUrg, MeArg, MeLys or MeHArg; A is a single bond, Gly, or a D or L isomer of Arg, Lys, Orn HArg, MeArg, MeLys, MeOrn, MeHArg or Gln D is a single bond, Gly, or a D or L isomer of Argm Lys, HArg, Me Arg, MeLys, MeHArg, Gln or Orn; B is OH, NH.sub.2, NHAlk or NH (CH.sub.2).sub.m NHR; Z is Phe, Phe(4'-Alk), Tyr(Alk), Ile or Tyr; X is a D or L isomer of Phe, Phe(4'-Alk), Val, Nva, Leu, Ile, Pba, Nle, Cha, Abu, Met, Chg, Tyr, Trp or Tyr(Alk); and Y is Val, Ile, Abu, Ala, Chg, Gln, Lys, Cha, Nle, Thr, Phe, Leu or Gly; m is 2 to 6; R is H or C(=NH)NH2 and * is to indicate D isomer, L isomer or a D,L mixture.
2. The compounds of claim 1 in which X is a D isomer.
3. The compounds of claim 1 in which X is a D-Tyr(Alk) and Y is Val.
4. The compounds of claim 1 in which X is D-Tyr(Alk), Y is Val, n is 1 and P is a single bond.
5. The compounds of claim 1 in which X is D-Tyr(Et), Y is Val, n is 1 and B is NH.sub.2.
6. The compound of claim 1 being [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9-desglycine]vasopressin.
7. The compound of claim 1 being [1,6-(6,6-cyclopentamethylene-2-amino-L-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine-9-desglycine ]vasopressin.
8. The compound of claim 1 being [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-desproline-8-arginine-9-argininami de]vasopressin.
9. The compound of claim 1 being [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-7-D-proline-9-desglycine]vasopressin .
10. The compound of claim 1 being [1,6-(6,6-cyclopentamethylene-2-amino-L-suberic acid)-2-(O-ethyl-D-rteiaubw)-4-valine-7-arginine-8-D-arginine-9-desglycine ]vasopressin.
11. The compound of claim 1 being [1.6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-O-ethyl-D-tyrosine)-4-valine-7-arginine-8-D-arginine-9-desglycine] vasopressin.
12. A pharmaceutical composition comprising a pharmaceutical carrier and, dispersed therein, an vasopressin antagonist effective but nontoxic quantity of a compound of claim 1.
13. The composition of claim 12 in which said compound is [1,6-(6,6-cyclopentamethylene-2-amino-D-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9-desglycine]vasopressin.
14. The composition of claim 12 in which said compound is [1,6-(6,6-cyclopentamethylene-2-amino-L-suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9-desglycine]vasopressin.
15. The method of inducing a vasopressin antagonist effect in a patient in need of such an effect comprising administering parenterally or intranasally to said patient a nontoxic, effective therefor quantity of a compound of claim 1.
16. The method of claim 15 in which the onist effect is manifested by a water diuresis.
17. The method of claim 15 in which the compound is [1,6-(6,6-cyclopentamethylene-2-amino-D suberic acid)-2-(O-ethyl-D-tyrosine)-4-valine-8-arginine-9desglycine]vasopressin.
Patent Citations (8)
Non-Patent Literature (6)
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