CA1102317A - Sarcosine su1 xx dehydroalanine su8 xx angiotensin ii derivatives - Google Patents

Abstract

Abstract of the Disclosure The sarcosine1 dehydroalanine8 angiotentin II
derivatives of the present invention are potent angiotensin blockers, having the additional advantage of not being angiotensin like.

Description

z3~7 SARCOSINEl D~HYDROAI.ANINE
ANGIOTENSIN II DER:[VATIVES

The present inven-tion relates to a group oE anyio--tensin II deriva-tives of the structure R Rl \C/ ', Sar-Arg-Val-Tyr-Ile-His-Pro-NHCCO2H ~I) whereln R is hydrogen, an alkyl radical contalning 1-8 carbon atoms or a phenyl radical; Rl is hydrogen or an alkyl radical containing 1-8 carbon atoms; and the stereochemical configura-tion of each of tha optically active amino acid residues is L or DL. ~
The abbreviations connote the amino acids defined ~ ~ ;
in accordance with the nomenclature rules published by the IUPAC-IUB Commission on Biochemical Nomenclature, Archives of Biochemistry and Biophysics, 150, 1-8 (1972).
Preferred compounds of the present invention are those of formula (I) wherein all of the optically active amino acid resi~ues are o~ the L-stereochemical configuration. ~
The alkyl radicals encompassed by the R and Rl ~; -substituents are illustrated by methyl, e-thyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and the branched-chain isomers thereof.
Also equivalent to the compounds of formula (I) for the purposes of this invention are the pharmaceutically acceptable acid addition salts thereof. Such acid addition salts can be derived from a variety of inorganic and organic acids such as sulfuric, phosphoric, hydrochloric, hydrobromic, hydriodic, nitric, sulfamic, citric, lactic, pyruvic, oxalic, ., ,~"

, . ' . .

3:a7 maleic, succinic, tartaric, cinnamic, acetic, trifluoroacetic, benzoic, salicylic, gluconic, ascorbic and related acids.
The manufacture o-f the instan-t novel compounds is conveniently`achieved by processes usually adapted to the syn-thesis of peptides. Thus, -the C-terminal arnino acid, optionally substituted with protec-ting groups, is coupled with the appropriate N-protected amino acid to af~ord the corresponding ~-protec-ted dipeptide. Removal of the N-pro-tecting group is followed, similarly, by coupling with the N~protec-ted amino acid required to produce the desired tripeptide. This sequential procedure is repeated until the desired octapap-tide derivative is produced. Formation of the C-terminal ~,~-dehydro amino acid derivative, i.e.
dehydroalanine, dehydrophenylalanine, dehydroalkylalanine and dehydrodialkylalanine, may be accomplished before coupling, as exemplified in Example 20, or after coupling, as exemplified in Example 14.
The aforementioned coupling processes are preferably carried out in accordance with s-tandard organic chemical techniques, whereby each intermediate peptide is produced as described hereinbefore and isolated prior to coupling with the next appropriate N-protec-ted amino acid active ester.
Alternatively, this sequential coupling process can be con-ducted by solid phase peptide synthesis, which consists of first attaching to a polymer support, e.g. chloromethylated copolys-tyrene-1% divinylbenzene polymer, the optionally N-protected C-terminal amino acid, followed by removal of the N-protecting gr~up and coupling, in the presence of a suit-able reagent, e.g. dicyclohexylcarbodiimide, successively with each of the appropriate N-protected amino acids.
The compounds of the present invention can also be ~23~

prepared by coupling active esters of -the N protected peptide blocks of -the appropriate size, which in turn can be obtained by stepwise synthesis as described in the preceding paragraphs ~ollowed by removal of the protecting groups.
The compounds of the present invention resemble angiotensin II except for the unnatural amino acids a-t the N-and C~terminals. These compounds are pharmacological agents particularly useful as angiotensin inhibitors and are additionally advan-tageous in view of the fact that they display antagonist activity without agonist activity. Their inhibitory proper-ty is demonstrated in the ~ollowing assay . procedures:
Virgin female Charles River rats weighing 200-250 y.
are injected 24 and 48 hours before use with diethyl stilbesterol, 1 mg./kg. subcutaneously, dissolved in eorn oil. The rats are sacrificed by cervical dislocation and the uterus is removed and a section of the u-terine horns ~`
mounted in a 2 ml. tissue bath containing a modified Tyrode solution maintained at 30C. and bubbled with 95% oxygen, 5% carbon dioxi~e. A series of control eontractions is elicited by alternate additions of angiotensin II, anti-diuretic hormone (~DH) and bradykinin. A solution of the test compound is then substituted for the plain Tyrode ~-solution and the treat contractions are obtained after an equilibration period of 15 or 30 minutes. Regularly timed contractions are elicited during the equilibration period in order to maintain the timed sequence of agonis-t additions.
Three control and three treat contractions are averaged to obtain the mean percent change. The compound is rated active if it effects a significant decrease in the con-tractions produced by the action of -the agonist.

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slood pressure is measured in Charles River albino rats anesthetized with pentobarbital sodium (50 mg./kg.) and pretreated with phenoxyhenzamine (30 m~./ky ) and propranolol (15 mg./kg.) while maintaining body -temperature at 32C.
The pressure is recorded from the carotid artery with a P~100 linear core pressure transducer, Physiograph. Both juyular veins are cannulated, one vein used for infusion of antagonists and the other for bolus injections of anglotensin II. An angiotensin II dose response curve is determined before each tes-t of the antagonists so that each animal serves as its own con-trol. An additional group of animals is tested to determine the effects oE a 15-minute placebo infusion of saline on angiotensin II responses. After de-termination of the angio-tensin II dose response curve, a placebo or inhibitor infusion is initiated and maintained for 15 minutes and continued ~
during the second dose response. Immediately after the -initial 15 minute infusion period the dose response curve is repeated. After the second dose response curve is obtained, the infusion of the antagonist is s-topped. Thereafter, representative doses of angiotensin II which produced approximately 20-25 mm of mercury response in the control period are injected at 10-15 minute intervals until the con-trol response is obtained. The time after infusion for the same response to appear is considered an indication of the antagonist's duration of activity. Relative activity is determined by comparing the ratio of the calculated doses obtained from the dose response curves of anyiotensin II
necessary to increase blood pressure 25 ~n of mercury before and after the inhibitor.
The invention will appear more fully from the examples which follow. These examples are given by way of illustration only and are no-t to b,e cons-trued as limitiny the inven-tion ei-ther i'n spiri-t or in scope, as many modi-fications both in materials and in me-thods will be apparent to those skilled in the art. In these examples temperatures are given in dec3rees Celsius, (C.) and quantities of ma-terials in par-ts by weight unless otherwise noted. The stereo- :
Ghemical confi.guration of each of the opticall,v active amino acids in the examples is L or DL.

3~7 __ 21.7 g of t-butoxycarbonylvaline was dis~olved in 200 ml of methylene chloride. 22.2ml of N-methylmorpholine was added to the solution. The solution was cooled to -70C. 13.1 ml of isobutylchloroformate was then added.
The reaction mixture was warmed up to -15C. and stirred for 5 minutes. The reaotion mixture was again cooled to -70C-23.2 g of tyrosine methyl ester hydrochloride was added to - the reaction mixture. The reaction mixture was allowed to warm ~o room temperature, and then was stirxed for 16 hours.
The reaction mixture was extracted three times with 0.5 M
potassium bisulfate and once with brine. The methylene ~; chloride solution was dried over anhydrous sodium sulfate, filtered and stripped of solvent The residue was dissolved in 200 ml of ethyl ether. The ether solution was added to cold rapidly stirring Skellysolve B. The white precipi tate was filtered and dried to afford the product t-butoxy-carbonylvalyltyrosine methyl ester.

29.6 g of t-butoxycarbonylvalyltyrosine methyl ester was dissolved in 255 ml. oP acetic acid. To this solu-tion was added 128 ml of 6N hydrochloric acid in dioxane.
; ~he reaction was allowed to stand for five minutes and the sol-vPnt was removed under vacuum. The residue was triturated with ethyl ether. The resultant precipitate was filtered, wa~hed with ethyl ether and dxied in a vacuum oven at 55C.
to afford valyltyrosine methyl ester hydrochloride.
; EX~UPLE 3 21.5 g of t-butoxycarbonylnitroarginine was dissolved in 200 ml of methylene chloride~ 15.0 ml of N-methylmorpholine ", 3~7 was add~d to the solution. 5'he solution was cooled to -70C.
8.8 ml of isobutyl chloroformate was then added. The reac-tion mixture was warmed up to -15C. and stirred for 5 minutes.
The reaction mi~ture was again cooled to -70~C. 22.3 g of valyltyrosine methyl ester hydrochloride was added to the reaction mixture. The reaction mixture was allowed to warm to room temperature, and then was stirred for 16 hours, rrhe reaction mixture was extracted three times with 0,5 M
potassium bisulfate and once with brine. The methylene chloride solutivn was dried over anhydrous sodium sulfate, filtered and stripped of solvent. The residue was dissolved in 200 ml of ethyl ethér. The ether solution was added to cold rapidly stirring Skellysolve B. The white precipitate was filtered and dried to afford the product t-butoxycarbonyl~
5 nitroarginylvalyltyrosine methyl ester.
EXA~.PLE_4 30~9 g of t-butoxycarbonylnitroarginylvalyl tyrosine methyl ester was dissolved in 177 ml. of a~atic acid. ~o this solution was added 88.5 ml of 6N hydrochloriG
acid in dioxane. The reaction was allowed to stand for five minutes and the solvent was removed under vacuum. The residue was triturated with ethyl ether. The resultant precipitate was filtered, washed with ethyl ether and dried in a vacu~n oven at 55C- to aPfoxd nitroarginylvalyl-5 tyrosine methyl ester hydrochloride.Ei~PLE 5 8.84 g of t-butoxycarbonylsarcosine was dissolved in 200 ml of methylen~ chloride. 10.5 ml of N-methyl-morpholine was added to the solution. rrhe solution was cooled to ~70 C. 6.1 ml of isobutyl chloroformate was then added.
he reaction mixture was warrned up to -15Co and stirred for 3~7 5 minutes. The reaction mixture was again cooled to -70C~
25.5 9 of nitroarginylvalyltyrosine methyl esthex hydro-chloride was added to the reaction mixture. The xeaction mixture was allowed to warm to xoom temperature, and then was stirred for 16 hours. The reaction mixture was extracted three times with 0.5 M potassium bisulfats and once with brine. The methylene chloride solution was dried over anhydrous sodium sulfate, ~iltered and stripped of solvent. The residue was dissolved in 200 ml of ethyl ether. The ether solution was added to cold rapidly stixxing Skellysolve B
The white pxecipitate was filtered and dried to afford the product t-butoxycarbonylsarcosylnitroarginylvalylt,yrosine methyl esterD
E~A~PLE 6 10.0 g of t-butoxycarbonylsarcosylnitroarginyl-valyltyrosine methyl ester was dissol~ed in 30 ml o methanol.
To this solution was added 60 ml of lN lithium hydroxide.
The reaction mixture was ~tirred for three hours, then neutralized with lN hydrochloric acid to pH 7. The solvent was removed by vacuum and the residue was dissolved in N,N-dimethylformamide. The solution was filtered and the solvent removed by vacuwn. The residue was dissolved in methanol/

2-propanol. The alcohol solution was added to 1 liter of ~old rapidly stirring ethyl ether. The white precipitate was filtered and dried in vacuo to afford t-butyloxycarbonyl-sarcosylnitroaryinylvalyltyrosine.
~A~PLE 7 -21.5 g of t-butoxycarbonylproline was diqsolved in 200 ml of methylene chloride. 22.2 ml of N-methylmorpholine was added to the solutlon. The solution was cooled to -70C, 13.1 ml of isobutyl chloroformate was then added. The , ., ..., .... ~

reaction mixture was warmed up to -15C. and stirred for 5 minu~es. The reaction mixture was again cooled to -70~.
15.6 g of serine methyl ester hydrochloride was added to the reaction mixture. The reaction mixture was allowed to warm to room temperature, and then stirred fox 16 hours. The reaction mixture was extracted three times with 0.5~
pota~sium ~isulfate and once with brine~ The methylene chloride solution was dried over anhydrous sodium sulfate, filterPd and stripped of solvent. The residue was dissolved in 200 ml of ethyl ether. The ether solution was added to cold rapidly stirring Skellysolve B. The white precipi-tate was filtexed and dried to afford the product t-butoxy-carbonylprolylserine methyl ester.
E~A~PLE 8 __ 24.4 g of t-butoxycarbonylprolylserine methyl ester was dissolved in 262 ml o dioxaneO To this solu-tion was added 141 ml. of 6N hydrochloric acid in dioxane.
The reaction was allowed to stand for ten minutes and the solvent was removed under vacuum. The residue was triturated 20 with ethyl ethex. The resultant product, prolylserine methyl ester hydrochloride, was a clear glass.
E~A~PLE 9 23,3 g of t-butoxycarbonylisoleucine was dissolved in 200 ml of methylene chloride. 33,3 ml of N-methyl-morpholine was added to the solution. The solution was cooledto -70C. 13.1 ml of isobutylchloroformate was then addedO
The reaction mixture was warmed up to -15C, and stirred for 5 minutes. The reaction mixture wa~ again cooled to -70C-Z6.0 g o histidine methyl ester dihydrochloride was added to ~he reaction mixture. The reaction mixture was allowed to warm to room temperature, and then was stirred or 16 _9_

3~

hours. The r~actlon mixture was extracted three times with 0.5 M potassium bisulfate and once with brin~. The methylene chloride solution was dried over anhydrous sodium sulfate, filtered and stripped of solvent. The xesidue was dissolved in 200 ml. of ethyl ether. The ether solution was added to cold rapidly stirring Skellysolve B. The white precipi-tate was filtered and dried to aford the product t-butoxy-carbonylisoleucylhistidine methyl estèr.
~PLE 10 29.4 g of t-butoxycarbonylisoleucylhistidine methyl ester was dissolved in 150 ml of methanol. To this solution was added 308 ml of lN lithium hydroxide. The reaction was stirred for three hours, then neutralized with lN hydrochloric acid to pH 3. The solven~ wa~ removed by vacuum and the residue was dissolved in N,N-dimethylformamide.
The solution was filtered and the solvent removed by vacuum.
The residue was dissolved in methanol/2-propanol. The alcohol solution was added to 2 liters of cold rapidly stirring,ethyl ether. The white precipi ate was filtered and dried in vacuo 0 to affoxd t-butoxycarbonylisoleucylhistidine hydrochloride.
E~A~PLE 11 10.1 g of t-butoxycarbonylisoleucylhistidine hydrochloride and 6.3 g of pxolylserine methyl ester hydxo-chloride were dissolved in 100 ml of dimethylformamide. The solution was,cooled to 0C. To the solution was added 3.4 g of l-hydroxybenzotriazole, 2.8 ml of N-methylmorpholine and 7.6 g of dicyclohexylcarbodiimide. The reaction mixture was stirred for two hours at 0C. and then wa~ allowed to stand at 4C. ~or sixteen hours. Dicyclohexylurea was filtered from the reaction mixture and was washed with ace-tone. 300 ml of ethyl acetate was added to the solution.

,. ~

~7 The solution was extracted three times with 300 ml saturated potassium bicarbonate and two times with 300 ml of brine.
The product was extracted into 300 ml of 2M potassium bisul-fate. The acidic solution was neutralized with potassium caxbonate. The slightly basic aqueous solution was extracted three times with 300 ml o methylene chlorideO The methylene chlorlde solu~ion, which contained the product, was dried o~er sodium sulfat ~ filtered and stripped of solvent under vacuum. The residue was dissolved in 100 ml of ethyl acetate.
The svlution was added to 1 liter of cold rapidly stirring Skellysolve B. The white precipitate was filtered and dried under vacuum at 55C. to afford the product t-but carbonylisoleucylhistidylprolylserine methyl ester.
EXA~PLE 12 .
8.5 g o t-butoxycarbonylisoleucylhistidylpxolyl-serine methyl ester was dissolved in 51 ml. o~ dioxane. To this solution was added 25.5 ml of 6N hydrochloric acid in dioxane. The reaction was allowed to s,tand for ten minutes and the solvent was removed under vacuum to afford isoleucyl- -histidylprolylserine methyl ester hydrochloridea ~ LE 13 9.8 g ~f t-butoxycarbonylsarcosylnitroarginyl-valyltyrosine and 7.6 g of isoleucylhlstidylprolylserine methyl ester hydrochloride were dissolved in 100 ml of di-methylforamide. The solution was cooled to 0C. To thesolution was added 2.03 g o~ l-hydroxybenzotriazole, 1.7 ml of N-methylmorpholine and 4O64 g of dicyclohexylcarbodiimide.
-~ The reaction mixture was stirred for two hours at 0C. and then was allowed to stand at 4C. for sixteen hours. Dicyclo-hexylurea was filtered from the reaction mixture and was washed with acetone. 300 ml of ethyl acetate was added to the ~olution. The solution was extracted three times with 300 ml saturated potassium bicarbonate and two times with 300 ml of hrine~ The product was extracted into 300 ml o~
2~ potassium bisulfate. The acidic solution was neutralized with potassium carbonate. The slightly basic aqueous solu~
tion was extracted three times with 300 ml of methylene chloride. The methylene chloride solution, which contained the product, was dried over sodium sulate, filtered and stripped of solvent under vacuum. The residue was dissolved in 100 ml of ethyl acetate. The solution was added to 1 liter of cold rapidly stirring Skellysolve B. The white precipitate was filtered and dried under vacuum at 55C.
to afoxd the product t-butoxycarbonyl~arcosylnitroarginyl-valyltyrosylisoleucylhistidylprolylserine methyl ester.
lS PLE 14 3.0 g of t-butoxycarbonylsarcosylnitroarginyl- -valyltyrosylisoleucylhistidylprolylserine methyl ester was dissolved in 20 ml of pyridine and 10 ml of triethylamine.-The solution was cooled in an ice bath. 0.51 g of tosyl chloride was added to the solution. At ten minute inter-vals, three additional 0.51 g batches of tosyl chloride were added. After standing ~or two hours, the reaction mixture was filtered. 200 ml of methylene chloride was added to the reaction. The solution was extracted three times with 5%
ammonium hydroxide in water. ~he solution was then dried over sodium sul~ate and stripped under vacuum~ The residue was taken up in 2% methanol/methylene chloride and passed through a silica gel column to remove the colored impurities and a~ford the pure product t-butoxycarbonylsarcosylnitro-arginylvalyltyrosylisoleucylhistidylprolyldehydroalaninemethyl ester.

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~ ~ PLE 15 2.09 g of t-butoxycaxbonylsarcosylnitroaryinyl-valyltyrosylisoleucylhistidylprolyldehydroalanine methyl ~ster was dissolved in 30 ml of dioxane. To this solution was added 60 ml. of lN lithium hydroxide. The reaction mixture was stirred for three hours, then neutralized with 1~ hydrochloric acid to p~ 7. The solvent was removed by vacuum and the residue was dissolved in N,N-dimethyl ormamide. The solut,ion was filtered and the solvent removed by vacuum. The residue was dissolved in dioxane and added to 300 ml of cold rapidly s~irring ethyl ether. The preci-; ` pitate was filtered and dried in vacuo to afford t-butoxy-carbonylsarcosylnitroarginylvalyltyrosylisoleucylhistidyl-prolyldehydroalanine.
E~AMPLE 16 1.07 g of t-butoxycarbonylsarcosylnitroarginyl- ,~
valyltyrosylisoleucylhistidylprolyldehydroalanine was stirred for thixty minutes at C. in 10 ml of hydrogen fluoride and 1 ml of anisole. The crude product was run in a counter-current distribution system of n-butanol:acetic acid:water (4 :1 :5) for 200 transfers. The solvent was removed under vacuum. The residue'was dissolved in water and lyophilized to af~ord the product sarcosylarginylvalyltyrosylisol~ucyl-histidylprolyldehydroalanine diacetic acid salt.
' A~PLE 17 52.8 g o ~-phenylserine was dried under vacuum at C for four hours. Thè anhydrous amino acid was s,uspended ... . , . , .. ~

~VZ~7 in 250 ml of methanol and the mixture was cooled to 10C.
96.4 ml of ~hionyl chloride was added gradually, keeping the temperature below 10C. The mixture was stirred for 24 hour~ a~ room temperature. The clear solution was stripped to dryness and the residue shaken with ether to af~ord ~-phenylserine methyl ester hydrochloride~
~MPLE 18 61.0 g of ~-phenylserine methyl ester hydrochloride was finely powdered and suspended in 500 ml of methylene chloride. 62.3 g of t-butoxycarbonylproline was then added, followed by 30~2 ml of N-methylmorpholine. A clear solu-tion was obtained after stirring for one-half hour under reflux. The solution was cooled to oC. and 59.6 g of dicyclohexylcarbodiimide in lO0 ml of methylene chloride was added~ with stirring~ After stand:ing for 16 hours at room temperature, the dicyclohexylurea was removed by filtra-tion. The iltrate was washed twice with 0.5 M potassium bisul~ate. The solution was then dried over sodium sulfatè
and the solvent removed in vacuo. The product was shaken with Skellysolve B, and the product was filtered off and dried to afford t-butoxycarbonylprolyl-~-phenylserine methyl ester.
EXAMPLE l9 3.92 g o~ t-butoxycarbonylprolyl-~-phenylserine methyl ester was dissolved in 40 ml o~ pyridine and the solution was cooled to 0C. 2.30 g of p-toluenesulfonyl chloridé was added and the mixture was stirred at 0C. until a clear solution resulted. The solution was allowed to stand for 16 hours at room temperature. The pyridine was stripped off under vacuum at room temperature. The residue was dissolved in chloroform, and the chloroform solution was washed three times with 0.5 M potassium bisulfate. The , . .... . _ solution was dried over sodium sulfate and the solven-t was stripped off to afford th~ product, a brittle foam, t-butoxy-carbonylprolyl-o-tosyl~ phenyl) serine methyl ester.
~XA~PLE 20 5.00 g of t-butoxycarbonylprolyl-o-tosyl-(~-ph~nyl) sexine methyl ester was dissolved in 50 ml o ethyl acetate and 1.81 g of dicyclohexylamine was added. A~ter standing for 16 hours, the dicyclohexylammonium tosylate was removed by filtration and washed with ethyl acetate The combined filtrates were washed twice with 0.5 M potassium bisulfate, dried over sodium sulfate, and the solvent was stripped off. The residual oil was chromatographed on neutral sili¢a using benzene as the eluting solvent to afford the purified solid product t-butoxycarbonylprolyl-dehydrophenylalanine methyl est~r.
~PLE 21 3.74 g of t-butoxycarbonylprolyldehydrophenyl-alanine methyl ester was di solved in 75 ml of ether. The solution was cooled to 0C. and saturated with hydrogen chlo~
ride gas. After a few minute~, the produck, prolyldehydro-phenylalanine methyl ester hydrochloride, began to crystallize. The mixture was allowed to stand for one houx at room temperature, and the product was filtered off and washed with ethyl ether.
A~PLE 22 6.20 g of proly~dehydrophenylalanine methyl ester hydrochloride was di~solved in 100 ml of dimethyl-formamide and 7.36 g o~ t-butoxycarbonylisoleucylhistidine was added, followed by 2.70 g of l-hydroxybenzotriazole, The solution was cooled to 0C and 4.16 g o dicyclohexyl-carbodiimide was added in one portion. Th~ mixture was ~V~L7 stirred ~or one houx at room temperature, and then allow~d to stand for 16 hours. The dicyclohexylurea which crystal-lized was removed by filtration and the solvent was removed under high vacuum at 40C. ~he viscous liquid which S remained was shaken with a large volume of water. The water was then decanted and the gummy product was rubbed with ether. The resulting product was purified by countercurrent distribution, 400 transfers, in a system o~ methanol:water:
chloroform:carbon tetrachloride (37:10:26:27) to afford t-butoxycarbonylisoleucylhistidylprolyldehydrophenylalanine methyl ester.
A~PLE 23 6.24 g of t-butoxycarbonylisoleucylhistidylprolyl-dehydrophenylalanine methyl ester was dissolved in 125 ml of ethyl acetate. The solution was cooled in an ice bath , and dry hydrogen chloride gas was bubbled in for one hour.
The product began to separate after a few minutes. At the conclusion of the reaction, the salt was filtered off and washed with ethyl,acetate to yield pure isoleucyl-histidylprolyldehydrophenylalanine methyl ester dihydro-- chloride.
E~A~PLE 24 6.52 y of ~-butoxycarbonylsarcosylnitroarginyl-valyltyrosine (Example 6) was dissolved in 130 ml of methanol:
acetic acid:water (8 :1:1). O.i g of palladium black was added and the mixture was hydrogenated at 60 psi and room temperature for 24 hours. The solvents were stripped off, the residue was dissolved in 50 ml of water, and the solu~

tion was lyophilixed. The residual powder was dissolved in 50 ml of water. 10 ml o lN hydrochloric acid was added and the solution lyophilized to give t-butoxycarbonyl-sarcosylarginylvalyltyrosine hydrochloride EXA~PL~ 25 .
6.44 9 of -t-butoxycarbonylsarcosylarginylvalyl-tyrosine hydrochloride and 5.97 g sf isoleucylhistidyl-prolydehydxophenylalanine methyl ester dihydrochloride were dissolved in 100 ml of dimethylformamide. 1.01 m~l of N-methylmorpholine was added, follvwed by 2.70 g of l-hydroxy-benzotriazole. The solution was cooled in an ice bath and 2.29 g of dicyclohexylcarbodiimide was added. The solution was stirred for 16 hours at room temperature. The dicyclo-hexylurea was filtered o and the filtrate was stripped to dryness under high vacuum. The residue was shaken with a large volume of water~ The product was then filtered and washed thoroughly with water to afford the pure product t-butoxycarbonylsarcosylarginylvalyltyrosylisoleucylhisti-dylprolyldehydrophenylalanine methyl ester dihydrochloride.
EX~PLE_26 11.86 g of t-bu~oxycarbonylsarcosylarginylvalyl-tyrosylisoleucylhistidylprolyldehydrophenylalanine methyl ester dihydrochloride was dissolved in 330 ml of methanol and the solution was cooled in an ice bath. 110 ml of lN
sodium hydroxide was added dropwise with rapid stirring over one-half hour. The solution was removed from the ice bath and the stirring was continued at room temperature for one additional hour. 6.0 y o acetic acid was added and the solution was stripped to dry~ess. The residue was shaken with water and the crude product was filtered and washed with water to afford t-butoxycarbonylsa'rcosylarginylvalyltyro-sylisoleucylhistidylprolyldehydrophenylalanine hydrochloride.
The product was purified by partition chromato-graphy on LH-20 as follows: 200 g of dry gel was swollen ,, ~

3~'7 by s-~irring the gel for 16 hours in two liters of the lower phase from ~utanol:acetic acid:w~ter ~4:1:5~. The swollen gel was packed into a column and washed with 2 liters of the upper pha~e. The product was dissolved in a minimum of upper phase and pipet-ted onto the col~nn in a thin band, which was allowed to soak in. The column was eluted with upper phase at a flow rate of 60 ml per hour~ and 25 ml fractions were collected. The fractions containing the pure product were pooled and stripped to dryness.
E~A~PLE 27 5.68 g of t-butoxycarbonylsarcosylarginyl-valyltyrosylisoleucylhistidylprolydehydrophenylàlanine hydrochloride was dissolved in 25 ml of acetic acid, and 50 ml of 6N hydrogen chloride in dioxane was added. The sol-ution was allowed to stand for one hour at room tempera-ture and the solven was removed under vacuum. The residue was stirred with ether and the product was filtered and washed with ether. The final product, sarcosylarginyl-trihydrochlo~ide, was homogeneous on thin layer chromato-graphy in n-butanol:acetic acid:water (7:1:2).
EX~PLE 28 2-Phenyl-4-isopropylidene-5-oxazolinone and other 2-phenyl-4-alkylidene-5-oxazolinones were prepared accordiny to the method described in E. Baltazzi, et.
al., Chemistry and Industry, February 13, 1954, p. 191

4.6g of sodium metal were added to 1200 ml f methanol. The sodium was allowed to react with the methanol, then 149g of benzyl mercaptan were added followed by 201g of 2 phenyl-4-isopropylidene-5-oxazolinone.
The reaction mixture was stirred for six hours then neutralized to pH5 with glacial acetic acid. The methanol was removed under vacuum. The residue was ~C12~7 subjected to colun~ chromatography on silica gel in 50%
hexane-50~ chloroform to remove the excess benzyl mercaptan.
This aEforded pure procluct, methyl N-benzoyl-S-benzyl pen:icillaminate.

~X~PLE 29 1000 ml of concentxated hydrochloric acid, 1000 ml of 90% formic acid and 1000 ml of distilled water were added to 286 g methyl N-benzoyl~S-benzylpenicillaminate. The reaction mixture was refluxed for forty-eight hours. The solvents were removed under vacuum, and residue was washed copiously with hot diethyl ether. The resultant precipitate was pure product, S-benzylpenicillamine hydrochloride.

1000 ml of methanol were cooled to -20C. To this was added dropwise 171 g of thionyl chloride. After the thionyl chloride had been added, 199 g of S-benzylpenicillamine hydrochloride were added. The reac-tion mixture was re- -fluxed for sixteen hours. The methanol was removed under vacuum. Fresh methanol was added to the reaction mixture then removed under vacuum. llhe residue-was triturated wlth die-thyl ether. The precipitate was filtered and washed with diethyl ether. This resulted in pure product, methyl S-benzylpenicillaminate hydrochloride.

:
146 g of t-butoxycarbonyl proline were dissolved in 1500 ml of methylene chloride. 150 ml of N-methylmorpholine were added to the solution. The solution was cooled to -70C. 89 ml of isobutylchloroformate were added. The renction mix-ture was warmed to ~15C. and then cooled to ~70C. 197 g of methyl S-benzylpenicillarninate hydrochloride ~z~

were added to the reaction mixture. The reaction mixture was stirred for sixteen hours at room temperature. The reaction mixture was extracted three times with l~OM
potassum bisulfate and once wit~l brine. The methylene chloride solution was dried ovex anhydrous sodiurn sulfate~
~iltered and stripped of solvent. The residue was dissolved in a minimum of diethyl ether. The ether solution was added to cold rapidly stirring hexane. The white precipitate was filtered and dried to afford the product, methyl t-butoxycarbonylprolylpenicillaminate.

230 g of methyl t-butoxycarbonylprolylpenicillaminate were dissolved in 1000 ml methylene chloride. 167 g of methyl trifluoromethylsulfonate were added to the solution.
The reac-tion mixture was stirred for six hours. 500 ml of eth~nol were added to the reaction mixture. The solvents were removed from the reaction under vacuum.
The residue was dissolved in 1000 ml of methylene chloride. 1~2 ml of triethylamine were added to the solution. The reaction mixture was allowed to stand for two hours. The solvent was removed under vacuum. The residue was subjected to column chromatograplly on silica gel in 20% hexane-80-% chloroform. This afforded pure product, methyl t-butoxycarbonylprolyl-2,3-dehydrovalinate.
E~MPL~ 33 .. .. _ .
16.3 g o~ methyl t-butoxycarbonylprolyl-2,3-dehydro-valinate were dissolved in 100 rnl of methanol. 150 ml of lM sodium hydroY.ide were added to the solution. The solution was stirred for six hours. The solution was neutralized to p~l3 with lM potassium blsulfate. The solvent ~C12~

was removed under vacuum. The residue was dissolved in ethyl acetate~ 'Lhe inorganic salts were filtered from the ethyl acetate solu-tlon. The ethyl acetate was removed under vacuum to yield the product, t-butoxycar~onyl-prolyl-2,3-dehydrovaline.
_Y~MPLE 34 - 1.2 g of t-butoxycarbonylprolyl-2,3-dehydrovalille were dissolvecl in 70 ml of dimethylformamide. 0.62 g of cesium carbonate and 10 g of chloromethylated polystyrene 2% divinylbenzene resin (0.35 milliequivalents/gram) were added to the solution. The reaction mixture was stirre~
for thirty-six hours at 60C~ The resin was fil-tered and washed with dimethylformamide, water, 2-propanol, and metllylene chloride. The resin was dried at 70C. under vacu~n to yield the diepeptide t-butoxycarbonylprolyl-2,3-dehydrovaline which was attached to the resin by a benzyl ester linkage.
EX~MPLE 35 To attach t-butoxycarbonyl-im-tosylhistidine to the butoxycarbonylprolyl-2,3-dehydrovaline resin an~ add the subsequent amino acids to obtain the desired peptide the following sequence was repeated for each amino acid on an automated peptide synthesizer.
The t-butoxycarbonyl protecting group of lOg oE
t~butoxyprolyl-2,3-dehydrovalyl resin was removed with 40 trifluoroacetic acid-60~ methylene chloride. This resin was treated twice with the acid solution to ensure the removal of the t-butoxycarbonyl group. The excess acid was rinsed off with methylene chloride followed by 2-propanol and the sequence of rinsing with methylene chloride followed by 2-propanol was repeated sevcral times.

Tile trifluoracetate salt of the peptide resin was neutralized Wi-til N,N-diisopropylethyl amine. The excess amine was rinsed off with methylene chloride followed by 2-propanol as above.
The deblocked pep-tide resin had attached to i-t t-butoxycarbonyl-im-tosylhidtidine via dicyclohexylcar-bodiimide. t-Butoxycarbonyl-im-tosylhistidine and dicyclo-hexylcarbodiimide were added in two-fold excess. 2.36 g of t-butoxycarbonyl-im-tosylhistidine dissolved in 2S ml of methylene chloride and 1.46 y of dicyclohexylcarbodiimide dissolved in 25 ml methylene chloride were added to the resin. The reaction was agitated for two hours. -The coupling was repeated. The resin was rinsed as before with methylene chloride followed by 2-propanol. The resin was acetylated two times with 0.4M acetic anhydride in methylene chloride.
The resin was rinsed as before with methylene chloride followed by 2-propanol.
The above sequence was r~peated for the addition of each amino acid until the desired pept:ide, t-butoxycarbonyl-sarcosyl-N -nitroarginylvalyl-0-2-bromobenzyloxylcarbonyl-tyrosylisoleucyl-im-tosylhistidylprolyl-2,3-dehydrovalyl resin was obtained.

100 ml of liquid hydrogen fluoride was added to 10 g of the protected peptide resin from the previous example in 10 ml of anisole. The reaction was stirred for twenty minutes at 4C. The hydrogen fluoride was removed under water aspirator vacuum with a stream of nitrogen gas. The resin was washed with eidthyl ether to remove the anisole.
The resin was then washed three times with 25 ml of distilled water. The water was removed from the product under vacuum.

3~

~he residue was subjected to column chromatography on siLica gel which had been modified with octadecyltrichlorosilane.
This afforded pure product, sarcosylargirlylvalyltyrosyl-isoleucylhistidylprolyl-2,3-dehydrovaline.

. Substitution of 2-phenyl-4-methylene-5-oxazolinone for the 2-phenyl-4-isopropylidine-5-oxazolinone in Example 28 and substantial repetitlon of the procedures described in Examples 28 through 36 gave sarcosylaryinylvalyltyrosyl~
isoleucylhistidylprolyldehydroalanine.

~ bstitution of 2-phenyl-4-benzylidine-5-oxazol.inone for the 2-phenyl-4-isopropylidine-5-oxazolinone in ~xample 28 and subs:tantial repetition of the procedures described in Examples 2~ through 36 gave sarcosylarginylvalyltyrosyl-isoleucylhistidylprolyldehydrophenylalanine.

Z3~7 EXAMPL~ 38 Described below are typical pharmaceutical composi-tions con-taining the compounds of this invention.

SUPPOSITORY
, Inyredient Amount (mg.)/Suppository , ~ , A compound of the instant invention (e.g., sarcosyl-L-arginyl-~valyl-L-tyrosyl-L-isoleucyl-L-histidyl-L-prolyl-dehydroalanine 10.0 mg.

10Theobroma Oil (Cocoa Butter) 990.0 mg.

The cocoa butter was melted, preferably on a water or steam bath to avoid overheating, then the active ingredient was suspended in the melt. Finally, the mass was poured into cooled metal molds, whi.ch were chrome plated and the melt was readily solidified. -Other acceptable pharmaceutical carriers for a suppository product are exemplified by trigylcerides of oleic, palmitic and stearic acids (cocoa butter), partially hydrogenated cottonseed oil, branched saturated fatty alcohols such as Suppository base G, hydroyenated coconut oil triglycerides of C12-C18 fatty acids, water dispersible vehicles such as the polyethylene glycols glycerin, gelatin, polyoxyl 40 stearates, polyethylene-4-sorbitan monostearates, and materials which can raise the melting poi.nt of the suppository base, such as beeswax, spermaceti, eta.

.

L'AI~LN'LI,L L
Ingredlent ~mount (my.) /5 cc.

A comi~ound of the instant invention (e.g., sarcosyl-L-arginyl~L-valyl-L-tyrosyl-L-iso]eucyl-L-histidyl-L-prolyl-dehydroalanine 1.0 my.
Phosphate buffer 1.0 ml.
Water for Injection, U.S.P. q.s. 5.0 ml.
The active ingredient was dissolved in the phosphate buffer and water for lnjection, the solution was filtered and filled into ampuls and ampuls were sealed. Sterili-zation of the ampuls was achieved by an appropriate sterilization procedure~
Other acceptable pharmaceutical carriers for a parenteral product are exemplified by vegetable oils such as peanut, corn, cottonseed, sesame oil, benzyl alcohol, saline, phosphate buffer, ethylene gl~col polymers, urea, dimethylacetamide, triton, dioxolanes, ethyl car-bonate, ethyl lactate, glycerol formal, isopropyl myristate, surfactants (nonionic, cationic, anioIIic), polyalcohols, ethanol.
In the compositions of the type described above, the novel compounds of this invention are present in an amount envisioned to produce the desired effect. ~lthough 1.0 or 10.0 mg.per unit dose is often convenient, considerably more or less active inyredient can be incorporated into each dosage unit if so desired. The daily dosage of these compounds is dependen-t upon various factors such as the particular compowld ernployed, the condi-tion ~or which the compound is administered and the patient's individual response.
The matter contained in each of the eollowing claims is to be read as part of the general description of the present invention.

-25~

Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for the preparation of a compound of the general formula (I) wherein R is hydrogen, an alkyl radical containing 1-8 carbon atoms, or a phenyl radical; R1 is hydrogen or an alkyl radical containing 1-8 carbon atoms; and the stereochemical configuration of each of the optically active amino acid residues is L or DL which comprises a) coupling of an active ester of an N-protected peptide with a C-terminal peptide, amino acid, or unsaturated amino acid, the reactants being selected in such a manner to afford the desired octapeptide of formula (I), said reaction carried out in a non-protic solvent in the presence of an organic base at room tem-perature; optionally followed by dehydrogenation of the amino acid in position 8 of the peptide chain, followed by removal of N-protecting groups; or b) coupling of a compound of the formula wherein R and R1 are defined as hereinbefore with N-pro-tected sarcosine in a non-protic solvent at room tempera-ture, followed by removal of the N-protecting groups and polymer support.

2. A process according to Claim 1 wherein the amino acid residues have L stereochemical configuration.

3. A process according to Claim 1 for the pre-paration of sarcosylarginylvalyltyrosylisoleucylhistidyl-prolyldehydroalanine which comprises coupling t-butoxy-carbonylsarcosylnitroarginylvalyltyrosine with isoleucyl-histidylprolylserine methyl ester hydrochloride in dimethyl-formamide in the presence of N-methylmorpholine followed by dehydrogenation of the serine in position 8 and removal of the protecting groups.

4. A process according to Claim 1 for the pre-paration of sarcosylarginylvalyltyrosylisoleucylhistidyl-prolyldehydrophenylalanine which comprises couping t-butoxycarbonylsarcosylarginylvalyltyrosine hydrochloride and isoleucylhistidylprolyldehydrophenylalanine methyl ester dihydrochloride in dimethylformamide in the presence of N-methylmorpholine followed by removal of the protecting groups.

5. A process according to Claim 1 for the preparation of sarcosylarginylvalyltyrosylisoleucylhistidylprolyl-dehydroalanine which comprises coupling polymer supported nitroarginylvalyltyrosylisoleucylhistidylprolyldehydro -alanine with N-protected sarcosine in methylene chloride in the presence of dicyclohexylcarbodiimide, followed by removal of the N-protecting groups and polymer support.

6. A process according to Claim 1 for the preparation of sarcosylarginylvalyltyrosylisoleucylhistidylprolylde-hydrophenylalanine which comprises coupling polymer supported nitroarginylvalyltyrosylisoleucylhistidylprolydehydro-phenylalanine with N-protected sarcosine in methylene chloride in the presence of dicyclohexylcarbodiimide, followed by removal of the N-protecting groups and polymer support.

7. A compound of the formula wherein R is hydrogen, an alkyl radical containing 1-8 carbon atoms, or a phenyl radical; R1 is hydrogen or an alkyl radical containing 1-8 carbon atoms; and the stereochemical configuration of each of the optionally active amino acid residues is L or DL, whenever pre-pared by the process of Claim 1.

8. A compound according to the formula as defined in Claim 7 wherein the amino acid residues have the L
stereochemical configuration, whenever prepared by the process of claim 2.

9. Sarcosylarginylvalyltyrosylisoleucylhistidyl-prolyldehydroalanine whenever prepared by the process of Claim 3 or 5.

10. Sarcosylargintylvalyltyrosylisoleucylhistidyl-prolyldehydrophenylalanine whenever prepared by the process of Claim 4 or 6.