CA2019006C - Antiherpes tetrapeptide derivatives having a cycloalkyl substituted aspartic acid side chain - Google Patents

Abstract

Disclosed herein are tetrapeptide derivatives of the formula X-NH-CHR1-C(W1)-NR2-CH[CH2C(O)-Y]-C(W2)-NH-CH[CR3(R5)-COON]-C(W3)-NH-CHR5-Z wherein X is a terminal group, for example, alkanoyl or phenylalkanoyl radicals, R1 and R5 are selected from amino acid or derived amino acid residues, R2 is hydrogen, alkyl or phenylalkyl, R3 and R4 are joined to form a cycloalkyl, W1, W2 and W3 are oxo or thioxo, Y is, for example, an alkoxy or a monosubstituted or disubstituted amino, and Z is a terminal unit, for example, hydrogen, COON or CH2OH. The derivatives are useful for treating herpes infections.

Description

201.9006 13-BG-D-26a Antiherpes Tetrapeptide Derivatives Having a Cvcloalkyl Substituted As' artic Acid Side Chain Field of the Invention This invention relates to peptide derivatives having antiviral properties and to means for using the derivatives to treat viral infections. More specifically, the invention relates to peptide derivatives (hereinafter called "peptiides") exhibiting activity against herpes viruses, to pharmacsutical compositions comprising the peptides, and to a method of using the peptides to treat herpes infections.
Background of the Invention The family of herpes viruses is responsible for a wide range of infections that afflict humans and many important domestic ani-mals. The diseases caused by these viruses range from bothersome cold sores to highly destructive infections of the central nervous system (encephalitis). The more common members of this family include herpes simplex virus (types 1 and 2) responsible for cold sores and genital lesions; varicella zc~ster virus which causes chicken pox and shingles; and Epstein-Barn virus which causes infectious mononucleosis. Although some significant advances have been made in the last decade in antiviral therapy, the need for effective, safe therapeutic agents for treating herpes viral infections continues to exist. For a recent review of current therapeutic agents in this area, see M.C. Nahata, "Antiviral Drugs: Pharmacokinetics, Adverse Effects and Therapeutic Use", J. Pharm. Technol., 3, 100 ( 1987).

20.0006 The present application discloses a group of peptide derivatives having activity against herpes viruses. The relatively selective action of these peptides against herpes viruses, combined with a wide margin of safety, renders the peptides as desirable agents for combating herpes infections.
The association of peptides with anti-herpes activity is uncommon. Instances of reports of such an association include B.M.
Dutia et al., Nature, 321, 439 (1986), E.A. Cohen et al., Nature, 321, 441 (1986), J.H. Subak-Sharpe et al., UK patent application 2185024, published July 8, 1987, E.A. Cohen et al., European patent application 246630, published November 25, 1987, R. Freidinger et al., European patent application 29'2255, published November 23, 1988, and R. Freidinger et al., U.S. patent 4,814,432, issued March 21, 1989. The subject peptides of the previous reports can be distinguished from the peptides of the present application by characteristic structural and biologic~~l differences.
Summary of the Invention:
The peptides of this invention are represented by formula 1 X-NH-CHR'-C(W')-NR2-CH[CHZC(O)-Y]-C(V~)-NH-CH[CR3(R4)-COOH]-C(W3)-NH-CHRs-Z 1 wherein X is (1-lOC)alkanoyl; (1-lOC)alkanoyl monosubstituted with halo, hydroxy or lower alkoxy; (:l-lOC)alkoxycarbonyl; benzoyl;
benzoyl monosubstituted or disubstituted with a substituent selected from halo, hydroxy, lower alkyl, lower alkoxy, phenyl, 2-carboxy-phenyl or benzyl; 2,2-diphenylacetyl; phenyl(2-lOC)alkanoyl;
phenyl(2-lOC)alkanoyl monosubstituted or disubstituted on the aromatic portion thereof with a substituent selected from halo, hydroxy, lower alkyl, lower alkoxy or phenyl; phenyl(3-lOC)-alkenoyl; (lower cycloalkyl)carbom~l; (lower cycloalkyl)carbonyl 201900u substituted with one to four substituents selected from halo or lower alkyl; cyclohexylcarbonyl substituted at position 2 with lower alkanoyl, phenyl(lower)alkanoyl or phenyl(lower)alkoxycarbonyl; 3,6-dimethyl-2-(phenylethoxycarbonyl)cyclohexylcarbonyl; or a straight or branched chain 1,4-dioxoalkyl containing from five to eleven carbon atoms;
R' is lower alkyl, hydroxy(lov~rer)alkyl, mercapto(lower)alkyl, methoxy(lower)alkyl, methylthio(lov~rer)alkyl, benzyloxy(lower)alkyl, benzylthio(lower)alkyl, carboxy(lowe;r)alkyl, lower cycloalkyl, (lower cycloalkyl)methyl, phenyl, phenylmethyl, 2-thienyl or 2-thienylmethyl;
RZ is hydrogen, lower alkyl or phenyl(lower)alkyl;
R3 and R4 together with the carbon .atom to which they are attached form a lower cycloalkyl;
RS is lower alkyl, lower cycloalkyl, or (lower cycloalkyl)methyl;
W', WZ, and W3 each independently is oxo or thioxo;
Y is a. (1-14C)allcoxy, (3-14)alkenyloxy, CH3(OCH2CH~o O wherein n is the integer 1, 2 or 3, lower cycloalkyloxy, lower alkoxy monosubstituted with a lower cycloalkyl, phenoxy, phenoxy monosubstituted with hydro~:y, halo, lower alkyl or lower alkoxy, phenyl(lower)alkoxy or phenyl(lower)alkoxy in which the aromatic portion thereof is substituted with hydroxy, halo, lower alkyl or lower alkoxy, or b. NR6R' wherein R6 is lower aalkyl and R' is lower alkoxy, or c. NR6R' wherein R6 is hydrogen or lower alkyl and R' is (1 14C)alkyl, lower cycloalkyl, lower alkyl monosubstituted with a lower cycloalkyl; phenyl, phenyl monosubstituted with halo, lower alkyl or lower alkoxy; phenyl(lower)alkyl, phenyl(lower)alkyl in which the aromatic portion thereof is substituted with halo, lower alkyl or lower alkoxy; or (Het)-lower alkyl wherein Het represents a five or six membered heterocyclic radical containing one or two heteroatoms selected from nitrogen, oxygen or sulfur, or ~~~19006 d. NR6R' wherein R6 and R' together with the nitrogen to which they are attached form a pyrrolidino, piperidino, morpholino, thiomorpholino, piperazino or 4-(lower alkyl)piperazino; and Z is hydrogen; COOH; CH2COOH; CH2CHZCOOH; CHZOH; 5-1 H-tetrazolyl; COORg wherein Rg is lower alkyl; CONR9R'° wherein R9 and R'° each independently is hydrogen or lower alkyl; or CON(R")OH wherein R" is hydrogen or lower alkyl; with the provisos that (1) when X is a (1-10(:)alkanoyl containing one or two carbon atoms (i.e. formyl or acetyl) then RZ is lower alkyl or phenyl lower alkyl, and that (2) when Z is hydrogen then R3 is hydrogen or lower alkyl and R' is lower alkyl or R3 or R4 together with the carbon atom to which they are attached form a lower cycloalkyl;
or a therapeutically acceptable salt thereof.
A preferred group of the peptides of this invention is represented by formula 1 whereiin X is (1-lOC)alkanoyl; (1-lOC)alkanoyl monosubstituted with chloro, fluoro, hydroxy or methoxy; benzoyl monosubstituted with phenyl, 2-carboxyphenyl or benzyl; phenyl(2-lOC)alkanoyl; phe:nyl(2-lOC)alkanoyl monosubsti-tuted on the aromatic portion thereof with a substitutent selected from halo, hydroxy, lower alkyl, lower alkoxy or phenyl; phenyl(3-lOC)alkenyl; (lower cycloalkyl)carbonyl; (lower cycloalkyl)carbonyl monosubstituted, disubstituted, trisubstituted or tetrasubstituted with methyl; cyclohexylcarbonyl substituted at position 2 with a phenyl-(lower)alkanoyl; la,2a,313,6~13-3,6-dimethyl-2-(phenyl-ethoxycarbonyl)cyclohexanecarbonyl or 6-methyl-2-(1-methylethyl)-1,4-dioxoheptyl; R' is as defined hereinabove; R2 is hydrogen or lower alkyl; R3 and R4 together with the carbon atom to which they are joined form a lower cycloalk:yl; Rs is 1-methylethyl, 1,1-dimethylethyl, 1-methylpropyl, 2-me;thylpropyl, 2,2-dimethylpropyl, cyclopentyl, cyclopentylmethyl, cycla~hexyl or cyclohexylmethyl; W', V~ and W3 are as defined hereinabove; Y is (1-14C)alkoxy, lower cycloalkyloxy, lower cycloalkylmethoxy, phenyl(lower)alkoxy, NR6R' wherein R6 is lower alkyl and R' is lower alkoxy, or NR6R' wherein R6 is hydrogen or lower alkyl and R' is (1-14C)alkyl, (3-.._ s 14C)alkenyloxy, CH3(OCHZCH~3-O, lower cycloalkyl, lower cycloalkylmethyl, phenyl, phenyl monosubstituted with halo, lower alkyl or lower alkoxy, phenyll;lower)alkyl, phenyl(lower)alkyl monosubstituted with halo, lower alkyl or lower alkoxy, (Het)-lower s alkyl wherein Het is a heterocyclic radical selected from 2-pyrrolyl, 2-pyridinyl, 4-pyridinyl, 2-furyl, 2-isoxazolyl and 2-thiazolyl, or NR6R' wherein R6 and R' together with the nitrogen atom to which they are attached form a pyrrolidino, piperidino or morpholino; and Z is as defined hereinabove; with the provisos that (1) when X is a (1-lOC)alkanoyl containing one or two carbon atoms then R2 is methyl, and that (2) when Z is hydrogen then R3 is hydrogen, methyl or ethyl and R4 is methyl or ethyl, or R3 and R4 together with the carbon atom to which they are attached form a lower cycloalkyl; or a therapeutically acceptable salt thereof.
is A more preferred group of the peptides is represented by formula 1 wherein X and Rs are as defined in the last instance; R' is lower alkyl, hydroxy(lowc;r)alkyl, methoxy(lower)alkyl, benzyloxy(lower)alkyl, lower cycloalkyl, (lower cycloalkyl)methyl, phenyl, phenylmethyl or 2-thienyl; RZ is hydrogen or methyl; R3 and R4 together with the carbon atom to which they are attached form a lower cycloalkyl; W', WZ and W3 acre oxo; Y is (1-14C)alkoxy, (3-14C)alkenyloxy, CH3(CICHzCH2)3-O, lower cycloalkyloxy, lower cycloalkylmethoxy, phenyl(lower)alkoxy, NR6R' wherein R6 is lower alkyl and R' is lower alkoxy, or NR6R' wherein R6 is hydrogen or 2s lower alkyl and R' is (1-14C)alkyl, lower cycloalkyl, lower cycloalkylmethyl, phenyl, phenyl(lowe;r)alkyl or pyridinyl(lower alkyl), or NRbR' wherein R6 and R' together with the nitrogen to which they are attached form a pyrrolidino, pipe;ridino or morpholino; and Z is hydrogen, CC10H, CH2CC10H, CH2CIH, s-1H-tetrazolyl, CONR9R'°
wherein R9 and R'° each independently is hydrogen or lower alkyl, or CON(R'1)OH wherein R" is hydrogen or methyl; or a therapeuti-cally acceptable salt thereof; with the previsos (1) and (2) noted in the preceding paragraph being applicable.

.~ 209006 A most preferred group of the peptides is represented by formula 1 wherein X is 2-ethyl'.butanoyl, 3-methylbutanoyl, 4-methylpentanoyl, octanoyl, 2-hydroxy-3-methylbutanoyl, 2-biphenylylcarbonyl, phenylacetyl, phenylpropionyl, 2-(1-methylethyl)-6-phenylhexanoyl, 2-(1-methylethyl)-6-phenyl-3-hexenoyl, cyclopropylcarbonyl, 2,2,3,3-tetramethylcyclopropylcarbonyl, cyclo-hexylcarbonyl, 2-methylcyclohexylcarbonyl, 2,6-dimethyl-cyclohexylcarbonyl, 2-(3-phenyl-1-o:KOpropyl)cyclohexanecarbonyl or 1 a,2a,3B,613-3,6-dimethyl-2-(phenyledloxycarbonylkyclohexylcarbonyl;
R' is lower alkyl, hydroxymethyl, 1~-hydroxyethyl, 1-benzyloxyethyl, cyclopentyl, cyclohexyl, cyclohexylmethyl, phenyl, phenylmethyl or 2-thienyl; R2 is hydrogen or methyl; R3 and R° together with the carbon atom to which they are attached form a lower cycloalkyl; RS
is 1-methylpropyl, 2-methylpropyl, 2,2-dimethylpropyl or cyclohexylmethyl, Wl, WZ and W3 are oxo, Y is hexyloxy, 1-methylheptyloxy, octyloxy, decylo:xy, trans-3-heptenyloxy, cis-3-octenyloxy, CH3(OCHZCHZ)3 O, c:yclopentyloxy, cyclohexyloxy, cyclohexylmethoxy, phenylpropoxy, :f~(Me)OMe, ethylamino, phenyl-amino, phenylethylamino, N-methyl-N-phenylethylamino, 2-pyridinyl-ethyl, N,N-dimethylamino, N,N-dieth~ylamino, N,N-diisopropylamino, N-methyl-N-octylamino, pyrrolidino, piperidino or morpholino; and Z
is hydrogen, COOH, CHZCOOH, 5-1H-tetrazolyl, CHZOH or CONR'R'° wherein R9 and R'° each independently is hydrogen, methyl, ethyl or propyl; with the proviso that when Z is hydrogen then R3 is hydrogen, methyl or ethyl and R4 is methyl or ethyl, or R3 and R4 together with the carbon atom to which they are attached form a lower cycloalkyl; or a therapeutically acceptable salt thereof.

Still another preferred group of the peptides is represented by formula 1 wherein X is 2-ethylbut<moyl, R' is 1,1-dimethylethyl or 1-methylpropyl, RZ is hydrogen, R3, R', Rs, W', WZ, W3 and Y are as defined in the last instance, and Z is hydrogen, COOH or CHZOH;
with the proviso that when Z is hydrogen then R3 and R4 each is methyl or ethyl, or R3 and R' together with the carbon atom to which they are attached form a lower cycloallcyl; or a therapeutically acceptable salt thereof.
Included within the scope of this invention is a pharma-ceutical composition comprising an anti-herpes virally effective amount of a peptide of formula 1, or a therapeutically acceptable salt thereof, and a pharmaceutically or veterinarily acceptable Garner.
Also included within the scoF~e of this invention is a cosmetic composition comprising a peptide oiP formula 1, or a therapeutically acceptable salt thereof, and a physiologically acceptable carrier suitable for topical application.
An important aspect of the :invention involves a method of treating a herpes viral infection in a mammal by administering to the mammal an anti-herpes virally effective amount of the peptide of formula 1, of a therapeutically acceptable salt thereof.
Another important aspect involves a method of inhibiting the replication of herpes virus by contacting the virus with a herpes viral ribonucleotide reductase inhibiting amount of the peptide of formula 1, or a therapeutically acceptable salt thereof.
Processes for preparing the: peptides of formula 1 are described hereinafter.

g Details of the Invention GENERAL
Alternatively, formula 1 c:an be illustrated as:

R
NH
x N HN
Z
R R qr R
The term 'residue' with reference: to an amino acid or amino acid derivative means a radical derived from the corresponding a-amino acid by eliminating the hydroxyll of the carboxy group and one hydrogen of the a-amino group.
In general, the abbreviations used herein for designating the amino acids and the protective groups are based on recommenda-lions of the IUPAC-IUB Commision of Biochemical Nomenclature, sew European Journal of Biochemistry 1:38, 9 (1984). For instance, Gly, Val, Thr, Ala, Ile, Asp, Ser and Leu represent the residues of glycine, L-valine, L-threonine, L-alanine,1L-isoleucine, L-aspartic acid, L-serine and L-leucine, respectively.
The asymmetric carbon atoms residing in the principal linear axis (i.e. the backbone) of the peptides of formula 1, exclusive of the terminal groups, have an S configuration. Asymmetric carbon atoms residing in the side chain of an amino .acid or derived amino acid residue, including those in terminal groups, may also have the R
configuration. Furthermore, with respexa to disubstituted benzoyl, disubstitued phenyl(1-lOC)alkanoyl, and disubstituted and trisubstituted cyclohexane;carbonyl, as defined for X of peptides of formula 1, the substituents are selected on the basis that they do not interfere with each others presence.

The symbol "Tbg" represents the amino acid residue of 2(S)-amino-3,3-dimethylbutanoic acid. ~f'he symbol "Cpg" represents the amino acid residue of (S)-a-aminocyclopentaneacetic acid. The symbol "Phg" represents the aumino acid residue of (S)-a-aminophenylacetic acid. Thr(OBzI) for the residue of 03-benzyl-L-threonine.
Other symbols used herein acre: Asp(cyPr) for the residue of (S)-a-amino-1-carboxycyclopropaner~cetic acid; Asp(cyBu) for the residue of (S)-a-amino-1-carboxycyclobutaneacetic acid; Asp(cyPn) for the residue of (S)-a-amino-1-carboxycyclopentaneacetic acid; and Asp(cyHx) for the residue of (S)-a-amino-1-carboxycyclohexaneacetic acid. Asp(pyrrolidino) is used for the residue of the amide 2(S)-amino-4-oxo-4-pyrrolidinobutanoic acid; and Asp(morpholino), Asp(NEtz) and Asp(N-Me-N-octyl) similarly represent the residues of the corresponding amides wherein the pyrrolidino is replaced with morpholino, diethylamino and N-methyl-N-octylamino, respectively.
The term 'halo' as used herein means a halo radical selected from bromo, chloro, fluoro or iodo.
The term "lower alkyl" as used herein, either alone or in combination with a radical, means straight chain alkyl radicals containing one to six carbon atoms and branched chain alkyl radicals containing three to six carbon atorns and includes methyl, ethyl, propyl, butyl, hexyl, 1-methylethyl, 1-methylpropyl, 2-methylpropyl and 1,1-dimethylethyl.
The term "lower alkenyl" as used herein means straight chain alkenyl radicals containing two to s;ix carbon atoms and branched chain alkenyl radicals containing three to six carbon atoms and includes vinyl, 1-propenyl, 1-methyle;thenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl and 2-butenyl.

-~ X019006 to The term "lower cycloalkyl" as used herein, either alone or in combination with a radical, means saturated cyclic hydrocarbon radicals containing from three to six carbon atoms and includes cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
The term "lower alkoxy" as used herein means straight chain alkoxy radicals containing one to four carbon atoms and branched chain alkoxy radicals containing three to four carbon atoms and includes methoxy, ethoxy, propoxy, 1-methylethoxy, butoxy and 1,1 dimethylethoxy. The latter radical is known commonly as tertiary butyloxy.
The term "lower alkanoyl" as used herein means straight chain 1-oxoalkyl radicals containing from. one to six carbon atoms and branched chain 1-oxoalkyl radicals containing four to six carbon atoms and includes acetyl, 1-oxopropyl, 2-methyl-1-oxopropyl, 1 oxohexyl and the like.
The term "(1-14C)alkyl" as used herein means straight and branched chain alkyl radicals containing from one to fourteen carbon atoms, respectively. The terms "(1-liDC)alkoxy" and "(1-14C)alkoxy"
as used herein, either alone or in combination with a radical, mean straight and branched chain alkoxy radicals containing from one to ten carbon atoms and one to fourdxn carbon atoms, respectively.
The term "(3-14C)alkenyloxy" mea~~s straight and branched chain alkenyloxy radicals containing from three to fourteen carbon atoms, and in which the double bond may be cis or trans and is positioned more than one carbon atom away from the oxygen atom of the radical; for example, 2-propenyloxy, :3-heptenyloxy and 3-octenyloxy.
The term "(1-lOC)alkanoyl" as used herein means straight or branched chain 1-oxoalkyl radicals camtaining from one to ten carbon atoms; for example, acetyl, 4-methyl-1-oxopentyl or (4-methyl-pentanoyl) or 1-oxooctyl (or octanoyll). The term "(3-lOC)alkanoyl"
as used herein means straight or braJnched chain 1-oxoalkyl radicals 201900fi containing from three to ten carbon atoms. The term "phenyl(2-lOC)alkanoyl" as used herein means phenyl substituted 1-oxoalkyl radicals wherein the 1-oxoalkyl portion thereof is a straight or branched chain 1-oxoalkyl containing from two to ten carbon atoms;
for example, 1-oxo-3-phenylpropyl a~ld 1-oxo-5-methyl-6-phenylhexyl.
The term "phenyl(3-lOC)alkenoyl" as used herein means phenyl substituted 1-oxoalkenyl radicals wherein the 1-oxoalkenyl portion thereof is a straight or branched chain 1-oxalkenyl containing from three to ten carbon atoms; for example, 2-methyl-1-oxo-3-phenyl-3-pentenyl.
The symbol "'~(CSNH]" used between the three letter representations of two amino acid residues means that the normal amide bond between those residues in the peptide, being represented, has been replaced with a thioamide bond.
The term "pharmaceutically acceptable carrier" or "veterinarily acceptable earner" as use herein means a non-toxic, generally inert vehicle for the active ingredient which does not adversely affect the ingredient.
The term "physiologically acceptable carrier" as used herein means an acceptable cosmetic vehiicle of one or more non-toxic excipients which do not react with or reduce the effectiveness of the active ingredient contained therein.
The term "veterinarily acceptable earner" as used herein means a physiologically acceptable vehicle for administering drug substances to domestic animals corr~prising one or more non-toxic pharmaceutically acceptable excipients which do not react with the drug substance or reduce its effectiveness.

The term "effective amount" means a predetermined antiviral amount of the antiviral agent, i.e. an amount of the agent sufficient to be effective against the viral organisms in vivo.
The term "coupling agent" as used herein means an agent capable of effecting the dehydrative coupling of an amino acid or peptide free carboxy group with a frEx amino group of another amino acid or peptide to form an amide bond between the reactants.
Similarly, such agents can effect tihe coupling of an acid and an alcohol to form corresponding esters. The agents promote or facilitate the dehydrative coupling by activating the carboxy group.
Descriptions of such coupling agents and activated groups are included in general text books of peptide chemistry; for instance, E.
Schroder and K.L. Lubke, "The Peptides", Vol. 1, Academic Press, New York, N.Y., 1965, pp 2-128, and K.D. Kopple, "Peptides and Amino acids", W.A. Benjamin, Inc., New York, N.Y., 1966, pp 33-51. Examples of coupling agents are thionyl chloride, diphenyl-phosphoryl azide, 1,1'-carbonyldiimidazole, dicyclohexylcarbodiimide, N-hydroxysuccinimide, or 1-hydroxybenzotriazole in the presence of dicyclohexylcarbodiimide. A very practical and useful coupling agent is (benzotriazol-1-yloxy)tris(dimethyhunino)-phosphonium hexafluoro-phosphate, described by B. Castro ea al., Tetrahedron Letters, 1219 (1975), see also D. Hudson, J. Org. Chem., 53, 617 (1988), either by itself or in the presence of 1-hydroxybenzotriazole.
Process The peptides of formula 1 can be prepared by processes which incorporate therein methods commonly used in peptide synthesis such as classical solution coupling of amino acid residues and/or peptide fragments, and if desired solid phase techniques. Such methods are described, for example, by E. Schra3er and K. Lubke, cited above, in the textbook series, "The Peptides: Analysis, Synthesis, Biology", E. Gross et al., Eds., Academic Press, New York, N.Y., 1979-1987, Volumes 1 to 8, and by J.M. Stewart and J.D. Young in "Solid Phase Peptide Synthesis", 2nd ed., :Pierce Chem. Co., Rockford, IL, USA, 1984.
A common feature of the aforementioned processes for the peptides is the protection of the reactive side chain groups of the various amino acid residues or derived amino acid residues with suitable protective groups which v~rill prevent a chemical reaction from occurring at that site until the protective group is ultimately removed. Usually also common i;s the protection of an a-amino group on an amino acid or a fragment while that entity reacts at the carboxy group, followed by the selective removal of the a-amino protective group to allow subsequent reaction to take place at that location. Usually another common feature is the initial protection of the C-terminal carboxyl of the aunino acid residue or peptide fragment, if present, which is to bea~ome the C-terminal function of the peptide, with a suitable protective group which will prevent a chemical reaction from occurring at that site until the protective group is removed after the desired sequence of the peptide has been assembled.
In general, therefore, a peptide of formula 1 can be prepared by the stepwise coupling in the order of the sequence of the peptide of the amino acid or derived amino acid residues, or fragments of the peptide, which if required are suitably protected, and eliminating all protecting groups, if present, at the completion of the stepwise coupling to obtain the peptide of formula 1. More specific processes are illustrated in the examples hereinafter.
With reference to the preparation of peptides of formula 1 in which Z is 5-1H-tetrazolyl, the derived amino acid residue containing the tetrazole can be prepared as follows: Boc-Leu-NHZ, for example, was converted to its corresponding nitrite derivative by treatment with p-toluenesulfonyl chloride in -- ~0~.9006 methylenedichloride in the presence of excess pyridine and a catalytic amount of 4-dimethylaminopyridine (Fieser and Fieser, "Reagents for Organic Synthesis", John Wiley arid Sons, Inc., New York, NY, USA, 1967, vol 1, p 1183). The rutrile derivative then was mixed with tributyl tin azide, J.G.A. Lui,~ten et al., Rec. Trav., 81, 202 (1962), giving a tetrazole tin intermediate [c~ K. Sisido et al., Journal of Organometallic Chemistry, 33, 337 (1971) and J. Dubois et al., J. Med. Chem., 27, 1230 ( 1984)]. The latter was treated with hydrogen chloride in diethyl ether to afford the desired tetrazole residue as a hydrochloride salt, for example, NHZCH[CHZCH(CH3)z]-5-1H-tetrazole dihydrochloride. The tetrazole residue, or its hydrochloride salt, was used for coupling with the appropriate amino acid or protected fragment, leading to the desired peptide of formula 1.
The peptide of formula 1 of this invention can be obtained in the form of a therapeutically acceptable salt.
In the instance where a particular peptide has a residue which functions as a base, examples of suich salts are those with organic acids, e.g. acetic, lactic, succinic, benzoic, salicylic, methanesulfonic or p-toluenesulfonic acid, as well as polymeric acids such as tannic acid or carboxymethyl cellulose, and also salts with inorganic acids such as hydrohalic acids, e.g. hydra~hloric acid, or sulfuric acid, or phorphoric acid. If desired, a particular acid addition salt is converted into another acid addition salt, such as a non-toxic, pharmaceutically acceptable salt, by treatment with the appropriate ion exchange resin in the manner described by R.A. Boissonnas et al., Helv. Chim. Acta, 43, 1849 (19fi0).
In the instance where a particular peptide has one or more free carboxy groups, examples of such salts are those with the sodium, potassium or calcium rations, or with strong organic bases, for example, triethylamine or N-mett~ylmorpholine.

a...
is Antiheroes Activi~
The antiviral activity of the; peptides of formula 1 can be demonstrated by biochemical, nnicrobiological and biological procedures showing the inhibitory effect of the compounds on the replication of herpes simplex viruses, types 1 and 2 (HSV-1 and HSV-2), and other herpes viruses, for example, varicella zoster virus (VZV), Epstein-Barr virus (EBV), .equine herpes virus (EHV) and cytomegalovirus.
Noteworthy is the fact that all of the aforementioned viruses are dependent on their own ribonucleotide reductase to synthesize deoxyribonucleotides for their replication. Although this fact may not be directly linked with the antiviral activity found for the present peptides, the latter compounds have been shown so far to have anti-viral properties against all viruses dependent on ribonucleotide reduc-tase to synthesize DNA for their replication.
In the examples hereinafter, the inhibitory effect on herpes ribonucleotide reductase is noted for exemplary peptides of formula 1. Noteworthy, in the connection with this specific inhibition of herpes ribonucleotide reductase, is the relatively minimal effect or absence of such an effect of the peptides on cellular ribonucleotide reductase activity required for normal cell replication.
A method for demonstrating the inhibitory effect of the peptides of formula 1 on viral replication is the cell culture technique; see, for example, T. Spector et al., Proc. Nati. Acad. Sci.
USA, 82, 4254 (1985).
The therapeutic effect of the peptides can be demonstrated in laboratory animals, for example, by using an assay based on genital herpes infection in Swiss Webster rnice, described by E.R. Kern, et al., Antiviral Research, 3, 253 (198:3).
When a peptide of this invention, or one of its therapeutically acceptable salts, is employed as an antiviral agent, it is administered topically or systemically to warm-blooded animals, e.g. humans, pigs or horses, in a vehicle comprising one or more pharmaceutically acceptable carriers, the proportion of which is determined by the solubility and chemical nature of the t~evtide, chosen route of administration and standard biological practice. For topical adminis-tration, the peptide can be formulated in pharmaceutically accepted vehicles containing 0.1 to 10 percent, preferably 0.5 to 5 percent, of the active agent. Such formulations can be in the form of a solution, cream or lotion.
For systemic administration, the peptide of formula 1 is administered by either intravenous, subcutaneous or intramuscular injection, in compositions with pharmaceutically acceptable vehicles or carriers. For administration by injection, it is preferred to use the peptide in solution in a sterile aqueous vehicle which may also contain other solutes such as buffers or preservatives as well as sufficient quantities of pharmaceutically acceptable salts or of glucose to make the solution isotonic.
Suitable vehicles or carriers for the above noted formulations are described in standard pharmaceutical texts, e.g. in "Remington's Pharmaceutical Sciences", 16th ed, Mack Publishing Company, Easton, Penn., 1980.
The dosage of the peptide will vary with the form of administration and the particular active agent chosen. Furthermore, it will vary with the particular host under treatment. Generally, treatment is initiated with small incrE;ments until the optimum effect under the circumstances is reached. In general, the peptide is most desirably administered at a concentration level that will generally afford antivirally effective results without causing any harmful or deleterious side effects.
With reference to topical application, the peptide is administered cutaneously in a suitable topical formulation to the infected area of the body e.g. the slan or part of the oral or genital cavity, in an amount sufficient to cover the infected area. The treatment should be repeated, for example, every four to six hours until lesions heal.
With reference to systemic administration, the peptide of formula 1 is administered at a dosage of 10 mcg to 1000 mcg per kilogram of body weight per day, although the aforementioned variations will occur. However, a dlosage level that is in the range of from about 50 mcg to 500 mcg pier kilogram of body weight per day is most desirably employed in order to achieve effective results.
Another aspect of this invention comprises a cosmetic composition comprising a herpes viral prophylactic amount of the peptide of formula 1, or a therapeutically acceptable salt thereof, together with a physiologically acceptable cosmetic Garner.
Additional components, for example, skin softeners, may be included in the formulation. The cosmetic formulation of this invention is used prophylactically to prevent the outbreak of herpetic lesions of the skin. The formulation can be applied nightly to susceptible areas of the skin. Generally, the cosmetic .composition contains less of the peptide than corresponding pharmacc;utical compositions for topical application. A preferred range of the amount of the peptide in the cosmetic composition is 0.01 to 0.2 :percent by weight.

20.9006 Although the formulation disclosed hereinabove are indicated to be effective and relatively safe medications for treating herpes viral infections, the possible concurrent administration of these formulations with other antiviral medications or agents to obtain beneficial results is not excluded. ;Such other antiviral medications or agents include acyclovir and antiviral surface active agents or antiviral interferons such as those disclosed by S.S. Asculai and F.
Rapp in U.S. patent 4,507,281, March 26, 1985.
The following examples ililustrate further this invention.
Solution percentages or ratios express volume to volume relationship, unless stated otherwise. Abbreviations used in the examples include Ac: acetyl; Boc: t-butyloxycarbonyl; BOP: (benzotriazol-1-yloxy)tris-(dimethylamino)-phosphonium hexafluorophosphate; Bzl: benzyl;
CHZC1Z: methylenedichloride; DIPE,A: diisopropylethylamine; DCC:
N,N-dicyclohexylcarbodiimide; DMh: dimethyl formamide; EtzO:
diethyl ether; EtOAc: ethyl acetate; EtOH: ethanol; HOBt: 1 hydroxybenzotriazole; HPLC: high performance liquid chromato graphy; MeOH: methanol; NMMI: N-methylmorpholine; TFA:
trifluoroacetic acid; THF: tetrahydrofnran. Temperatures are given in degrees centrigrade.
EXamplf; 1 Preparation of the Intermediate Boc-.Asnfl(S)-methylheptyloxyl-OH
A solution of Boc-Asp-OB~zI (10.2 g, 31.6 mmol) in acetonitrile was added at 0 ° to a mixture of N,N'-carbonyldiimi-dazole (5.6 g, 34.7 mmol), DIPEA, (8 ml, 46 mmol) and 2(S)-octanol (6 ml, 37.9 mmol) and 4-dumethylaminopyridine (200 mg).
The mixture was stirred for 3 h and then concentrated to dryness.
The residue was dissolved in EtOAc. The solution was washed with 1N aqueous HCI, 1N aqueous NaHC03, dried (MgSO,) and concentrated. The resultant oil ways purified by chromatography (SiOZ, eluent: hexane-EtOAc, 7:3) to give Boc-Asp[1(S)-methyl-heptyloxy]-OBzl (92% yield). Hydr~~genation of the latter compound in the presence of 20% Pd(OH),/C in ethanol solution afforded a quantitative yield of the title compound as a solid. NMR(200 MHz, CDCl3)8 0.9(m,3H), 1.25(m,IOH), 1.45(s,9H), 2.8(dd,lH), 3.0(dd,lH), 4.6(m,lH), 4.95 (m,lH) and 5.55(d,:lH).
Analogous esters of Boc-Asp-OH were prepared in the same manner.
Examvle 2 Preparation of the Intermediate Boc-Asn(NEt,)-OH
BOP (2.20 g, 5.0 mmol) was added under NZ to a cooled (0 °) solution of Boc-Asp-OBzI ( 1.90 g, 4.6 mmol) in CH2C12 (50 ml).
After 3 min NHEt~.HCI (0.55 g, 5.0 mmol) and DIPEA (2.4 ml, 13.8 mmol) were added. The resultant solution was stirred at 20-22 ° for 18 h. The solution was washed with 10% aqueous citric acid (2 X), 10% aqueous NaHC03 (2 X) and brine (2 X). The organic layer was dried (MgS04) and concentrated to give an oil.
After Si02 chromatography of the oil using hexane-EtOAc (7:3) as the eluent, Boc-Asp(NEtz)-OBzI (1.55 g, 89%) was obtained as an oil.
Under a NZ atmosphere, a solution of the latter compound ( 1.55 g, 4.09 mmol) in MeOH (100 ml) was mixed with 5% Pd/C (155 mg).
The mixture was shaken on a Parr apparatus under H2 (50 psi) for 90 min. The mixture was filtered tluough a 45 m membrane and the filtrate concentrated to give Boc-,Asp(NEt,~-OH (1.15 g, 98%) as an oil. The structure of the product was confirmed by NMR.
In the same manner, corresponding N-substituted asparagine analogs were obtained by replacing IVI~t~.HC1 with the appropriate amine or amine salt (e.g. pyrrolidine or N,O-dimethylhydroxylamine hydrochloride).

The intermediates of examples 1 and 2 or their analogs can be incorporated into corresponding peptides of formula 1 according to the procedures of examples 7 or 8.
Examvle 3 5 Preparation of d,l-cis-6-(3-Phen~rl-1-oxopronvl)-3-cyclohexene-1-carboxvlic acid A Grignard reagent was prepared in THF (40 ml) from phenylethyl bromide (2.75 ml, 20 rnmol) and Mg turnings (0.51 g, 21 mmol) while the mixture was heated at reflux temperature for 1 10 h. A solution of 3a,4,7,7a-tetrahydro-1,3-isobenzofurandione (3.04 g, 20 mmol) in Et~O (100 ml) was cooled to -40°. The solution of the Grignard reagent was added dropwis~e via a cannula over 15 min to the stirred cooled solution. The reaction mixture was allowed to warm to room temperature over 15 min and then stirred at that 15 temperature for 2 h. The reaction mixture was quenched at 0° with 1N aqueous HCl and then extracted with EtOAc. The organic phase was extracted with 1N aqueous NaOH. The latter aqueous phase was washed with EtOAc, rendered acidic with 6N aqueous HCl and extracted with EtOAc. The latter extract was dried (MgSO,) and 20 concentrated to dryness. The crude product was purified by chroma-tography (Si02; eluent: hexane-EtOAc, 1:1) to give the title com-pound (2.99 g, 58%). The NMR of the product was in agreement with the assigned structure.
The title compound was incorporated as a N-terminal residue into the pentultimate protected interrr~ediate of the desired peptide of formula 1 according to the procedure of example 7. Subsequent hydrogenolysis simultaneously removed any benzyl protecting groups of the pentultimate intermediate and reduced the double bond in the terminal residue to afford the corresponding peptide of formula 1 wherein X is d,l-cis-2-(3-phenyl-1-oxopropylkyclohexanecarbonyl.
The diastereoisomers can be separated by HPLC.

20.9006 Examvle 4 Preparation of la,2a,3B,6B-3.6-Dimethvlcvclohexane-1,2-dicarboxvlic Acid Monovhenylethvl Ester A solution of trans,trans-2,4-~hexadiene (1.10 g, 13.4 mmol) and malefic anhydride ( 1.31 g, 13.4 mmol) in benzene ( 15 ml) was heated at 85° for 4 h. The mixtm~e was cooled and diluted with EtOAc. The organic phase was washed with H20, dried (MgSO,) and concentrated to give 3aa,4B,7B;7aa-tetrahydro-4,7-dimethyl 1,3-isobenzofurandione (2.00 g, 83%) as a white solid. A solution of the latter compound (500 mg) in THIF was added to an excess of magnesium phenylethoxide in THF at -20 °. The stirred reaction mixture was allowed to come to room temperature and then stirred for 18 h at that temperature. Isolation of the product in the manner described in example 4 gave la,2a,3B,6B-3,6-dimethyl-4-cyclohexene-1,2-dicarboxylic acid monophenylethyl ester (310 mg). Subsequent hydrogenation [H2, 20% Pd(OH)y~C,EtOH,3h] yielded the title compound in quantitative yield. The NMR spectrum was in agreement with the assigned structure for the product.
The title compound was incorporated as a N-terminal reside according to the procedure of example 7 to yield desired peptides of formula 1 as a mixture of diastereoi.somers which can be separated by HPLC.
ExamylE; 5 Preparation of (S)-a-Amino-1-carboxvcycloalkylacetic Acid Intermediates These intermediates, which can be used to prepare peptides of formula 1 in which R' and R4 are joined to form a lower cycloalkyl can be prepared according to the method of M. Bochenska and J.F.
Biernat, Rocz. Chem., 50, 1195 (197fi); see Chem. Abstr., 86, 43990r (1977).

20~L9006 More specifically exemplifie,i, (t)-Boc-Asp(cyPn)(OBzI)-OH
was prepared as follows: To a solution of 1-bromocyclopentane-carboxylic acid ethyl ester [17.1 g, 77.3 mmol, described by D.N. Harpp et al., J. Org. Chem., 46, 3420 (1975)] and freshly distilled ethyl isocyanoacetate (12.7 g, 122 mmol) in a mixture of dimethylsulfoxide and Et~O (1:1, 12CI ml) was added sodium hydride (4.5 g, 60°k dispersion in mineral oil, 122 mmol) in small portions over 5 h. The resulting red slurry was stirred at room temperature for 16 h after which time it was t~~eated with a saturated aqueous solution of ammonium chloride (5 ml). The mixture was diluted with water (500 ml). The resulting mixture was extracted (2X) with ethyl acetate. The ethyl acetate layers were combined and washed with water (2X) and then with brine. Drying (MgSO,), filtering and concentration of the extract afforded a dark red oil. This material was subjected to flash chromatography through a 5 x 25 cm column of silica gel [eluent: ethyl acetate-hexane (1:10)]. Concentration of the appropriate fractions provided a-cyano-1-carboxycyclopentaneacetic acid diethyl ester as a clear colorless viscous liquid ( 13 g, 66 %).
The latter compound (13 g, :il mmol) was mixed with 6 N
aqueous HCl (60 ml) at 0 °. After dissolution, the reaction mixture was heated in a oil bath at 120 ° for 24 h. After this time water was removed from the mixture using a dry ice rotory evaporator.
The resulting white solid was dried under high vacuum for 18 h.
The dried material was dissolved in a mixture of dioxane (50 ml) and 3N aqueous NaOH (52 ml). A solution of di(tertiarybutyl) dicarbonate (14.6 g, 67 mmol) in di~oxane (25 ml) was added to the solution. The mixture was stirred at room temperature for 16 h.
Additional 3N aqueous NaOH was added at intervals insuring a pH
of about 10. The mixture was diluted with water (500 ml) and extracted (2X) with EtzO (200 ml). The aqueous phase was rendered acidic (pH = 3) with solid citric acid and extracted (2X) with ethyl acetate (300 ml). The combined ethyl acetate extracts were washed with water (3x) and brine. Drying, filtering and concentration of the extract afforded Boc-Asp(cyPn)-OH as a white solid (14 g, 96%).
To a solution of the latter compound (7.2 g, 25 mmol) in dry DMF (50 ml) was added KZCO3 (7.6 g, 55 mmol) and benzyl bromide (6.6 ml, 55 mmol). The reaction mixture was stirred at room temperature for about 7 h. Thereafter, the reaction mixture was poured into a mixture of water (500 ml) and ethyl acetate (350 ml).
The organic phase was washed with water (2X) and brine. Drying, filtering and concentration of the c;xtract provided a pale yellow viscous liquid. This material was subjected to flash chromatography through a 5 x 20 cm column of silica gel, eluting with hexane-ethyl acetate ( 12:1 ). Concentration of the appropriate fractions provided the dibenzyl derivative of Boc-Asp-(cyPn)-OH as a low melting white solid ( 11 g, 94%). The dibenzyl product was dissolved in THF ( 100 ml) and an aqueous solution of Li~OH (23.5 ml, 1N) was added.
After 4 h, the reaction mixture was :poured into water and extracted (3X) with EtzO. The aqueous phase was rendered acidic with 10%
aqueous citric acid and extracted (2~;) with ethyl acetate. The ethyl acetate layers were combined, .dried (MgSO,), filtered and concentrated to provide Boc-Asp(cy:Pn)(OBzI)-OH as a clear color less gum (7.3 g, 82%).
Example; 6 Preparation of the Intermediate Boc-Asn(cvPn)(OBzI)yr~CSNHILeu-OBzI
The title compound is obtained by stirring a mixture of the protected dipeptide Boc-Asp(cyPn)(OBzI)-Leu-OBzI (5.5 mmol) and Lawesson's reagent (2.7 mmol), see 'U. Pederson et al., Tetrahedron, 38, 3267 (1982), in toluene at reflu~: temperature for 2 h; followed by pouring the cooled reaction mixture onto a column of silica gel (3.5 x 30 cm) and eluting the column with CHZC12.

--~ ~~19~~fi Analogs thioamides intermediates are prepared in the same manner by replacing Boc-Asp(cyPn)(OBzI)-Leu-OBzI with the appropriate protected dipeptide.
Example 7 General Procedure for the Solid Phase Preyaration of Peytides of Formula 1 A modified version of the solid phase method of R.B.
Mernfield, J. Am. Chem. Soc., 85, 2.149 (1963) was used to prepare the peptides preferably using a BHA-photoresin such as [4-(2-chloropropionyl)phenoxy)acetamidomethyl-copoly(styrene-1% divinyl-benzene) resin, see D. Bellof and M. Mutter, Chemia, 39, 317 (1985). Protection of free carboxy ,groups and hydroxy groups was provided by the Bzl protective group. Typically, a Boc-amino acid, representing the C-terminal unit of the desired peptide, e.g. Boc-Leu-OH, was linked to the above noted BHA-photoresin by the potassium fluoride method of K. Horiki et al., Chem. Ixtt., 165 (1978), using 9 molar equivalents of KF and 3.6 molar equivalents of Boc-l:xu-OH, for example in DMF at 70 ° C for 24 hours, to give { 4- { 2- { Boc-leucine } propionyl }:phenoxy } acetamidomethyl-copoly(styrene-1% divinylbenzene) resin. The dried amino acid-solid support typically showed a leucine content of 0.6 to 0.8 mmol/g for the product, as determined by deprotection of an aliquot, followed by picric acid titration, B.F. Gisin, Anal. Chim. Acta, 58, 248 (1972). .
The latter amino acid-solid support was used to build up the required sequence of units (i.e. amino acid residues, derived amino acid residues) of the desired peptide by solid phase methodology. Two molar equivalents (per mole of the amino acid-solid support) of the appropriate amino acid residues were coupled serially to the solid support system using BOP (2 molar equivalents), or BOP (2 molar equivalents)/HOBt (1 molar equivalent), in the presence of N-methyl-morpholine (6 molar equivalents) in dry DMF. Completion of coupling was verified by a negative :ninhydrin test, E. Kaiser et al., Anal Biochem., 34, 595 ( 1979). Double coupling was used when necessary.
Cleavage of the protected peptide from the solid support was accomplished by irradiation at 330 nm in EtOH/DMF (1:4) at 0 °
5 under an argon atmosphere for 6 to 18 h. Protective groups (Bzl), if present, were removed from the cleavage product by hydrogenolysis over 5°70 or 10%v Pd/C or 20% Pd(OH~/C by standard procedures (cf. example 1). Purification of the final product was performed by reversed-phase HPLC to better than 95% homogeneity 10 using 0.06% aqueous TFA/0.6% TFA in acetonitrile gradients.
Example; 8 Preparation of (C,HO,CHO-Tb~-Asp(wrrolidino)-Asp(cyPn)-Leu-OH
(Example of a solution phase proced~.we for preparing compounds of formula 1 ) 15 To a solution of Boc-Asp(cyF'n)(OBzI)-OH (5.3 g, 14 mmol, described in example 3) in dry CH;zCl2 (50 mL), BOP (6.8 g, 16 mmol), NMM (4.6 mL, 42 mmol) and the (4-methylphenyl)sulfonic acid salt of LeuOBzl (6.6 g, 16 mmol) were added successively. The reaction mixture was stirred at room temperature for 5 h, after which 20 time it was poured into a two component system of EtOAc (500 mL) and a saturated aqueous solution of TfaHC03 (400 mL). The organic phase was washed with water and brine. Drying (MgSO,~, filtering and concentrating of the organic phase afforded a dark yellow oil.
This material was purified by flash chromatography [SiOz, eluent:
25 hexane-EtOAc (6:1)] to provide Boc-Asp(cyPn)(OBzI)-Leu-OBzI as a clear colorless gum (7 g, 86%, mi:Kture of diastereoisomers).
The latter compound (7 g, 12 mmol) was mixed with CH2Clz (4 mL). TFA (6 ml) was added to the mixture and the resulting solution was stirred for 30 min at room temperature. Thereafter, the majority of the solvent was evaF~orated and the residue was poured into a two component system o:f EtOAc (200 ml) and a saturated aqueous solution of NaHC03 (400 mL). Drying (MgSO,), filtering, and concentrating of the organic phase afforded the amine dipeptide H-Asp(cyPn)(OBzI)-Leu-OBzI as a clear colorless gum (mixture of diastereoisomers). The mixture was separated on a wATERS"LC-500 [2 columns of SiO~, eluent: hexane-EtOAc (1.5:1)]. The first diastereomer to elute (ca 2g, white solid) proved to provide the more active end products (peptides of formula 1). This observation proved general for all corresponding c;ycloalkyl aspartic acid derivatives made. For convenient storage of material, the pure amine dipeptide was treated briefly with 6N HCl/dioxane and concentrated to afford the hydrochloride salt as a white foam.
The latter hydrochloride salt (400 mg, 0.8 mmol) was coupled with Boc-Asp(pyrrolidino)-OH (250 mg, 0.87 mmol), following the same general procedure used above for preparing Boc-Asp(cyPn)(OBzI)-Leu-OBzI. The crude product was purified by flash chromatography [Si02, eluent: hexane-EtOAc (1:1)] to provide Boc Asn(pyrrolidino)-Asp(cyPn)(OBzI)-Leu-OBzI as a white foam (530 mg, 91%).
The previous material (280 mg, 0.38 mmol) was treated with 6 N HCl/dioxane (4 mL) for 3CI min at room temperature. The solvent was removed and the residue was pumped under high vacuum for 18 h. The resulting white foam was coupled to Boc-Tbg-OH
(1.1 eq) in essentially the same manner as was done for the previous coupling. The crude product was purified by flash chromatography [Si02, eluent: hexane-EtOAc (1:1)] to provide Boc-Tbg-Asp(pyrrolidino)-Asp(cyPn)(OBzI)-Leu-OBzI as a white foam (280 mg, 85%).
The latter material (65 mg, 0.075 mmol) was treated with 6N
HCl/dioxane for 20 min at room temperature. The solvent was evaporated. The residue was pumped under high vacuum for 2 h Trade-mark then dissolved in CH2C12 (1 mL). NMM (30 N.I,, 0.27 mmol) was added to the solution, followed b~y a premixed solution of 2-ethylbutanoic acid (12 ~rT., 0.095~ mmol) and BOP (40 mg, 0.09 mmol) in CHZCIz (0.5 mL). The reaction mixture was stirred at room temperature for 14 h, after which time it was poured into a two component system of EtOAc (20 mL) and a saturated aqueous solution of NaHCO, (20 mL). ThE; organic phase was separated, washed with water and brine, dried (MgSO~, filtered and concentrated to afford a yellow gum.. This material was purified by flash chromatography [Si02, eluent: C:H2Cli EtOAc (12:1)] to provide (CZHs~CHO-Tbg-Asn(pyrrolidino)-Asp(cyPn)(OBzI)-Leu-OBzI as a solid gum (49 mg, 75%).
The latter material (30 mg, 0.035 mmol) was dissolved in MeOH (1.5 mL). 20% Pd(OH)~/C (2.0 mg) and ammonium formate (20 mg) were added to the mixture. The mixture was stirred under an atmosphere of hydrogen for about 3 h. The reaction mixture was filtered through diatomaceous earth and the filtrate was concentrated.
The residue was dissolved in water ( 15 mL) containing a few drops of a saturated aqueous solution of NaHC03. The solution was washed (2X) with Et~O. The aqueous phase then was acidified with solid citric acid and extracted (2X) with EtOAc. The combined EtOAc extracts were dried (MgS04), filtered and concentrated to afford the title compound of this example as a white solid (20 mg, 83%), MS: 680(M+1).
The procedure of examples 7 or 8 can be used to prepare the peptides of formula 1; for example, see the peptides listed in the table of example 9. Commercially available Boc-amino acids were used. Unnatural amino acids were used in their Boc protected form;
they were either commercially av;~ilable, readily prepared from commercially available corresponding; amino acids by reaction with di-tertiary-butyl carbonate, or prepared by standard methods.

20~~00~

With reference to the preparation of peptides of formula 1 wherein RZ is lower alkyl or phenyl(lower)alkyl, the required N-alkylated Boc amino acids can be prepared by standard N-alkylation of corresponding Boc-amino acids. For example, Boc-N-Me-Asp-(NEt~-OH was obtained by reacting Boc-Asp(NEt,~-OH of example 2 with 2.5 molar equivalents of methyl iodide and 2.1 molar equivalents of potassium hydride in TIC at 0 ° for 18 h to give a mixture of Boc-N-Me-Asp(NEt~-OH and its corresponding methyl ester. The mixture was esterified fully (diazomethane) and then saponified (NaOH/HZO/dioxane) to yield the desired compound.
Example 9 Inhibition of Hert~es Simplex Virus (HSV, type 1) Ribonucleotide Reductase a) Preyaration of Enzyme HSV-1 ribonucleotide reductase (partially purified) was obtained from quiescent BHK-~21/C 13 cells infected with strain F HSV-1 virus at 10 plaque forming units/cell as described by E.A. Cohen et al., J. Gen. Virol., 66, 733 (1985).
b) Assav and Results for Exemylified Peptides By following the procedure described by P. Gaudreau et al., J. Biol, Chem., 262, 12413 (1,987), the assay results listed in the following table were obtained. The assay result for each peptide is expressed as the concentration of the peptide producing 50% of the maxinnal inhibition (ICS) of enzyme activity. The number of units of the enzyme preparation used in each assay was constant, based on the specific activity of the enzyme preparation. T'he results are relative to the activity obtained in control experiments without peptide and represent the mean of four assays that varied less than 10%
with each other.

20~~9~06 TABLE
Peptide F~AB/MS ICS

(M+H)+ (p.M) (C2HS~CHCO-Tbg-Asp(pyrro- 680 0.1 lidino)-Asp(cyPn)-Leu-OH

(see example 8) (CzHs~CHCO-Tbg-Asp(pyrro- 666 0.08 lidino)-Asp(cyBu)-Leu-OH

(CZHs~CHCO-Tbg-Asp[1(S)- 725 0.54 methylheptyloxy]-Asp(cyBu)-Leu-OH

(CzHs~CHCO-Tbg-Asp[1(S)- 761 ' 0.37 methylheptyloxy]-Asp(cyPn)-Leu-OH

(CzHs)zCHO-Tbg-Asp(N-Me-N-738 0.22 octylamino)-Asp(cyBu)-Leu-OH

(C2H5)zCHO-Tbg-Asp(pyrro- 674 ' 0.5 lidino)-Asp(cyPn)-(L-leucinol) (CZHS~CHCO-Tbg-Asp(pyrro- 666 0.27 lidino)-Asp(cyPn)-(L-leucinol 1. MS: (M+Na)+

Other examples of peptides of formula 1 are:
PhCHZCH2C0-Thr-N-Me-Asp(NEtz)-Asp(cyBu)-Leu-OH
[2-(2'-carboxy)biphenylyl]carbonyl-'Chr-Asp(NMez)-Asp(cyPr)-Leu-OH
octanoyl-Ile-Asp(octyloxy)-Asp-Leu-IVHz (CH3)zCHCHzCHzCO-NHCH(cyclohe:Kylmethyl)-CO-Asp(tridecyloxy)-Asp(cyHx)-Leu-OH

2o~,~oa~

[3-methyl-2-(1-methylethyl)-1-oxobutyl]-Ile-Asp(pyrrolidino)-Asp(cyHx)-Leu-OH
PhCHZCH2C0-Ile-N-Me-Asp(pyrrolidino)-Asp(cyBu)-Leu-OH and (CH3)ZCHCH2CH2C0-Ile-N-Me-Asp(cxtyloxy)-Asp(cyPn)-Leu-OH.

Claims (8)

1. A peptide of formula 1 X-NH-CHR1-C(W1)-NR2-CH[CH2C(O)-Y]-C(W2)-NH-CH[CR3(R4)-COOH]-C(W3)-NH-CHR5-Z
wherein X is 2-ethylbutanoyl, R1 is 1,1-dimethylethyl or 1-ethylpropyl, R2 is hydrogen, R3 and R4 together with the carbon atom to which they are attached form a lower cycloalkyl; R5 is 1-methylpropyl, 2-methylpropyl,

2,2-dimethylpropyl or cyclohexylmethyl, W1, W2 and W3 are oxo, Y is hexyloxy, 1-methylheptyloxy, octyloxy, decyloxy, trans-3-heptenyloxy, cis-3-octenyloxy, CH3(OCH2CH2)3-O, cyclopentyloxy, cyclohexyloxy, cyclohexylmethoxy, phenylpropoxy, N(Me)OMe, ethylamino, phenylamino, phenylethylamino, N-methyl-N-phenylethylamino, 2-pyridinylethyl, N,N-dimethylamino, N,N-diethylamino, N,N-diisopropylamino, N-methyl-N-octylamino, pyrrolidino, piperidino or morpholino, and Z is hydrogen, COOH or CH2OH; or a therapeutically acceptable salt thereof.
2. A peptide of claim 1 selected from the group of:
(C2H5)2CHCO-Tbg-Asp(pyrrolidino)-Asp(cyPn)-Leu-OH
(C2H5)2CHCO-Tbg-Asp(pyrrolidino)-Asp(cyBu)-Leu-OH
(C2H5)2CHCO-Tbg-Asp[1(S)-methylheptyloxy]-Asp(cyBu)-Leu-OH

(C2H5)2CHCO-Tbg-Asp[1(S)-methylheptyloxy]-Asp(cyPn)-Leu-OH
(C2H5)2CHCO-Tbg-Asp(N-Me-N-octylamino)-Asp(cyBu)-Leu-OH
(C2H5)2CHCO-Tbg-Asp(pyrrolidino)-Asp(cyBu)-(L-leucinol) and (C2H5)2CHCO-Tbg-Asp(pyrrolidino)-Asp(cyPn)-(L-leucinol).

3. A pharmaceutical composition comprising a peptide as recited in claim 1, or a therapeutically acceptable salt thereof, and a pharmaceutically or veterinarily acceptable carrier.

4. A cosmetic composition comprising a peptide as recited in claim 1, or a therapeutically acceptable salt thereof, and a physiologically acceptable carrier suitable for topical application.

5. The use of a peptide as defined in claim 1, or a therapeutically acceptable salt thereof, for treating herpes viral infection in a mammal.

6. The use as defined in claim 5 wherein the herpes viral infection is a herpes simplex viral infection.

7. The use of a peptide as defined in claim 1, or a therapeutically acceptable salt thereof, for inhibiting the replication of herpes virus.

8. The use of a peptide as defined in claim 1, or a therapeutically acceptable salt thereof, for inhibiting herpes viral ribonucleotide reductase.