AU6663794A - Processes and intermediate compounds useful for the preparation of platelet glycoprotein iib/iiia inhibitors - Google Patents

Description

TITLE

Processes And Intermediate Compounds Useful For The Preparation Of Platelet Glycoprotein IIb/IIIa

Inhibitors FIELD OF THE INVENTION

This invention relates to processes for the synthesis of platelet glycoprotein IIb/IIIa

inhibitors, and to intermediate compounds useful in said processes.

BACKGROUND OF THE INVENTION

Activation of platelets and the resulting

platelet aggregation and secretion of factors by the platelets have been associated with different

pathophysiological conditions including cardiovascular and cerebrovascular thromboembolic disorders, for example, the thromboembolic disorders associated with unstable angina, myocardial infarction, transient ischemic attack, stroke, atherosclerosis and diabetes. The contribution of platelets to these disease

processes stems from their ability to form aggregates, or platelet thrombi, especially in the arterial wall following injury. Platelets are known to play an essential role in the maintenance of hemostasis and in the pathogenesis of arterial thrombosis. Platelet activation has been shown to be enhanced during coronary thrombolysis which can lead to delayed reperfusion and reocclusion. Clinical studies with aspirin, ticlopidine and a monoclonal

antibody for platelet glycoprotein IIb/IIIa provide biochemical evidence for platelet involvement in unstable angina, early stage of acute myocardial infarction, transient ischemic attack, cerebral ischemia, and stroke.

Platelets are activated by a wide variety of agonists resulting in platelet shape change, secretion of granular contents and aggregation. Aggregation of platelets serves to further focus clot formation by concentrating activated clotting factors in one site. Several endogenous agonists including adenosine diphosphate (ADP), serotonin, arachidonic acid, thrombin, and collagen, have been identified. Because of the involvement of several endogenous agonists in activating platelet function and aggregation, an inhibitor which acts against all agonists would represent a more efficacious antiplatelet agent than currently available antiplatelet drugs, which are agonist-specific.

Current antiplatelet drugs are effective against only one type of agonist; these include aspirin, which acts against arachidonic acid; ticlopidine, which acts against ADP; thromboxane A₂ synthetase inhibitors or receptor antagonists, which act against thromboxane A₂; and hirudin, which acts against thrombin.

Recently, a common pathway for all known

agonists has been identified, namely platelet

glycoprotein IIb/IIIa complex (GPIIb/IIIa), which is the membrane protein mediating platelet aggregation. A recent review of GPIIb/IIIa is provided by Phillips et al. (1991) Cell 65: 359-362. The development of a GPIIb/IIIa antagonist represents a promising new approach for antiplatelet therapy. Recent studies in man with a monoclonal antibody for GPIIb/IIIa indicate the antithrombotic benefit of a GPIIb/IIIa antagonist.

There is presently a need for a GPIIb/IIIa-specific antiplatelet agent which inhibits the

activation and aggregation of platelets in response to any agonist. Such an agent should represent a more efficacious antiplatelet therapy than the currently available agonist-specific platelet inhibitors.

GPIIb/IIIa does not bind soluble proteins on unstimulated platelets, but GPIIb/IIIa in activated platelets is known to bind four soluble adhesive proteins, namely fibrinogen, von Willebrand factor, fibronectin, and vitronectin. The binding of

fibrinogen and von Willebrand factor to GPIIb/IIIa causes platelets to aggregate. The binding of

fibrinogen is mediated in part by the Arg-Gly-Asp (RGD) recognition sequence which is common to the adhesive proteins that bind GPIIb/IIIa.

Several RGD-containing peptides and related compounds have been reported which block fibrinogen binding and prevent the formation of platelet thrombi. For example, see Cadroy et al. (1989) J. Clin. Invest. 84: 939-944; Klein et al. U.S. Patent 4,952,562, issued 8/28/90; European Patent Application EP 0319506 A; European Patent Application EP 0422938 Al; European Patent Application EP 0422937 A1; European Patent Application EP 0341915 A2; PCT Patent Application WO 89/07609; PCT Patent Application WO 90/02751; PCT Patent Application WO 91/04247; and European Patent Application EP 0343085 A1. Compounds of formula (I) are difficult to

prepare. For example, the process described in United States Patent Application No. 07/949,085 uses N-α methyl Tosyl protected Arginine as the initial

starting material and modified solid phase

methodology in the synthesis. This method is not applicable to multi-gram and kilogram preparations. Thus, there is a need for a process capable of

providing these compounds that utilizes inexpensive, readily available starting materials, cheaper coupling reagents and techniques that do not require high dilution . It is an objective of the present invention to provide such a process. It is also an objective of the present invention to provide intermediate

compounds useful in said processes for the preparation of platelet glycoprotein IIb/IIIa inhibitors.

Finally, it is an objective of this invention to provide processes for the prepartion of said

intermediate compounds.

DETAILED DESCRIPTION OF THE INVENTION

This invention is directed to a processes for the preparation of compounds of formula:

comprising the steps of:

(a) coupling an amino tripeptide of formula:

, wherein Z is a suitable carboxylic acid protecting group and Y is a suitable amine protecting group, with a carboxylic acid derivitive of formula: , wherein G is a suitable amine protecting group, to produce a protected linear peptide of

formula:

, (b) removing the Z and G protecting groups of the product of Step (a) to produce a deprotected linear peptide of formula:

;

(c) cyclizing the deprotected linear peptide of Step (b) to produce a cyclic peptide of formula:

;

(d) converting the benzyl ester group of the product of Step (c) to an acid of formula:

; (e) deprotecting the amine group of the product of Step (d) to produce an amine of formula:

; and

(f) reacting the product of Step (e) with a reagent capable of converting an amine to guanidine to produce a compound of formula (I), wherein: w is 0 or 1;

R¹ is , wherein: p and p' are 0 or 1; R¹⁹ is a C₆-C₁₄ saturated, partially

saturated, or aromatic carbocyclic ring system or heterocyclic ring system composed of at least 1-3 heteroatoms selected from N, O, S; all these ring systems may be optionally substituted with 0-2 R⁷;

R¹⁷ and R¹⁶ are independently selected from the group: hydrogen;

C₁-C₄ alkyl, optionally substituted with halogen;

C₁-C₂ alkoxy;

benzyl;

R¹⁵ and R¹⁸ are independently selected from the group: hydrogen,

C₁-C₈ alkyl substituted with 0-2 R⁸, C₂-C₈ alkenyl substituted with 0-2 R⁸, C₂-C₈ alkynyl substituted with 0-2 R⁸,

C₃-C₈ cycloalkyl substituted with 0-2

R⁸,

C₆-C₁₀ bicycloalkyl substituted with

0-2 R⁸ aryl substituted with 0-2 R¹³, a heterocylic ring system composed of 5-10 atoms including 1-3 nitrogen, oxygen, or sulfur heteroatoms,

optionally substituted with 0-2 R¹³;

R¹⁵ and R¹⁷ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³; R¹⁸ and R¹⁶ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁵ and R¹⁴ can alternatively join to form a 5-8 membered carbocyclic ring

substituted with 0-2 R¹³, when R¹⁷ is H;

R⁷ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀

arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R²⁰, -C(=O)R²⁰,-

OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl optionally substituted with -NR²⁰R²¹;

R⁸ is independently selected at each

occurrence from the group:

=O, F, Cl, Br, I, -CF₃, -CN, -CO₂R²⁰, -C(=O)NR²⁰R21, -CH₂OR²⁰, -OC(=O)R20,

-CH₂NR²⁰R²¹, -NR²⁰R²¹;

R¹³ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀ arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆ cycloalkoxy, -OC(=O)R20, -C(=O)R20,- OC(=O)OR²°, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl (substituted with -NR²⁰R²¹);

R²⁰ is independently selected at each

occurrence from the group: H, C₁-C₇ alkyl, aryl, -(C₁-C₆

alkyl) aryl, or C₃-C₆ alkoxyalkyl;

R²¹ is independently selected at each

occurrence from the group:

H, C₁-C₄ alkyl, or benzyl;

R¹¹ is H or C₁-C₈ alkyl; R¹² is H or C₁-C₈ alkyl;

R¹⁴ is H or C₁-C₈ alkyl;

R² is H, C₁-C₈ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₁-C₆ cycloalkylethyl, phenyl, phenylmethyl, CH₂OH, CH₂SH,

CH₂OCH₃, CH₂SCH₃, CH₂CH₂SCH₃, (CH₂)_sNH₂, (CH₂)_sNHC(=NH) (NH₂), (CH₂)_sNHR²¹, wherein s = 3-5; R¹² and R² can be taken together to form-(CH₂)_t- , wherein t = 2-4, or -CH₂SC (CH₃)₂-;

R³ is H or C₁-C₈ alkyl;

A is selected from the group:

-(C₁-C₇ alkyl)-. , wherein q is 0,1, , wherein q is

0,1, , wherein v is 0-3 and provided that W is 0,

- (CH₂)_mO-(C₁-C₄ alkyl)-, wherein m = 1,2,

- (CH₂)_mS-(C₁-C₄ alkyl)-, wherein m = 1,2;

R³ and A may also be taken together to form _,

wherein n = 0-1 and provided that w = 0;

R⁹ is H, C₁-C₈ alkyl; and

R⁵ is H, C₁-C₈ alkyl.

In a preferred embodiment, the above described process provides compounds of formula (I) wherein:

R¹⁹ is selected from:

, ,

,

or

;

R¹⁵ and R¹⁸ are independently selected from

H, C₁-C₄ alkyl, phenyl, benzyl,

phenyl- (C₂-C₄) alkyl, C₁-C₄ alkoxy;

R¹⁷ and R¹⁶ are independently H or C₁-C₄

alkyl; R⁷ is H, C₁-C₈ alkyl, phenyl, halogen, or C₁-C₄

alkoxy;

R¹¹ is H or C₁-C₃ alkyl;

R¹² is H or CH₃; A is -(C₁-C₅ alkyl)- , wherein q is 0,1; , wherein q is 0,1

- (CH₂)_mS(CH₂)₂-, wherein m = 1,2 ,.

wherein v is 0-3 and provided that w = 0 R³ and A may be taken together to form , wherein, n = 0- 1 and provided that w = 0;

R⁹ is H, C₁-C₃ alkyl ;

R⁵ is H, C₁-C₃ alkyl.

In the most preferred embodiment, the above-described process provides compounds of formula (I) wherein:

R⁵, R⁹, R¹⁶, R¹⁷ and R¹⁸ are H; R¹¹, R¹², and R¹⁴ are H or CH₃;

R¹⁵ is H, C₁-C₄ alkyl, phenyl, benzyl, or

phenyl- (C₂-C₄) alkyl; and

R³ is H or C₁-C₃ alkyl.

The above described process specifically

provides a compound of formula: w is 1;

p is 0;

R¹⁹ is ;

R⁵, R⁹, R¹⁷, R¹⁵,R¹¹, R¹², R¹⁴ are H;

R² is C₂H₅;

R³ is CH₃; and

A is -(CH₂)₃-. This invention also provides a process for the preparation of an intermediate compound of formula:

comprising cyclizing a compound of formula:

wherein :

Y is pthalyl, t-BOC, CBZ, CBZNH-C (=N-CBZ), t-BOCNH-C(=Nt-BOC)-, Tos-NH-C (=NH) -, CF₃C(=O)-;

R¹ is , wherein: p and p' are 0 or 1;

R¹⁹ is a C₆-C₁₄ saturated, partially

saturated, or aromatic carbocyclic ring system or heterocyclic ring system composed of at least 1-3 heteroatoms selected from N, O, S; all these ring systems may be optionally substituted with 0-2 R⁷;

R¹⁷ and R¹⁶ are independently selected from the group: hydrogen;

C₁-C₄ alkyl, optionally substituted with halogen;

C₁-C₂ alkoxy;

benzyl;

R¹⁵ and R¹⁸ are independently selected from the group: hydrogen,

C₁-C₈ alkyl substituted with 0-2 R⁸, C₂-C₈ alkenyl substituted with 0-2 R⁸, C₂-C₈ alkynyl substituted with 0-2 R⁸,

C₃-C₈ cycloalkyl substituted with 0-2 R⁸, C₆-C₁₀ bicycloalkyl substituted with 0-2 R⁸, aryl substituted with 0-2 R¹³, a heterocylic ring system composed of 5-10 atoms including 1-3 nitrogen, oxygen, or sulfur heteroatoms,

optionally substituted with 0-2 R¹³;

R¹⁵ and R¹⁷ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³; R¹⁸ and R¹⁶ can alternatively join to form a

5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁵ and R¹⁴ can alternatively join to form a 5-8 membered carbocyclic ring

substituted with 0-2 R¹³, when R¹⁷ is

H;

R⁷ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀

arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R²⁰, -C(=O)R²⁰,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl optionally substituted with -NR²⁰R²¹;

R⁸ is independently selected at each

occurrence from the group:

=0, F, Cl, Br, I, -CF₃, -CN, -CO₂R²⁰, -C(=O)NR²⁰R²¹, -CH₂OR²⁰, -OC(=O)R20, -CH₂NR²⁰R²¹, -NR²⁰R²¹;

R¹³ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀ arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R20, -C(=O)R20,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl (substituted with -NR²⁰R²¹⁾;

R²⁰ is independently selected at each

occurrence from the group:

H, C₁-C₇ alkyl, aryl, -(C₁-C₆

alkyl) aryl, or C₃-C₆ alkoxyalkyl;

R²¹ is independently selected at each

occurrence from the group: H, C₁-C₄ alkyl, or benzyl; R¹¹ is H or C₁-C₈ alkyl;

R¹² is H or C₁-C₈ alkyl;

R¹⁴ is H or C₁-C₈ alkyl;

R² is H, C₁-C₈ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₁-C₆ cycloalkylethyl, phenyl, phenylmethyl, CH₂OH, CH₂SH,

CH₂OCH₃, CH₂SCH₃, CH₂CH₂SCH₃, (CH₂)_sNH₂, (CH₂)_sNHC(=NH) (NH₂), (CH₂)_sNHR²¹, wherein s = 3-5;

R¹² and R² can be taken together to form- (CH₂)_t- , wherein t = 2-4, or -CH₂SC (CH₃) ₂-;

R³ is H or C₁-C₈ alkyl; is selected from the group:

-(C₁-C₇ alkyl)-; , wherein q is 0,1; , , wherein v is 0-3,

-(CH₂)_mO-(C₁-C₄ alkyl)-, wherein m = 1,2,

-(CH₂)_mS-(C₁-C₄ alkyl)-, wherein m = 1,2;

R³ and A may also be taken together to form , wherein n = 0-1;

R⁹ is H, C₁-C₈ alkyl; and R⁵ is H, C₁-C₈ alkyl.

In a preferred embodiment, the above described process provides an intermediate compound of formula (II) wherein:

Y is phthalyl, CBZ, CBZNH-C(=NCBZ)-,

Tos-NH-C(=NH)-;

R¹⁹ is selected from: , ,

,

or

;

R¹⁵ and R¹⁸ are independently selected from

H, C₁-C₄ alkyl, phenyl, benzyl, phenyl- (C₂-C₄) alkyl, C₁-C₄ alkoxy;

R¹⁷ and R¹⁶ are independently H or C₁-C₄

alkyl;

R⁷ is H, C₁-C₈ alkyl, phenyl, halogen, or

C₁-C₄

alkoxy;

R¹¹ is H or C₁-C₃ alkyl;

R¹² is H or CH₃;

A is C₁-C₇ alkyl.

, wherein q is 0,1, , wherein q is , wherein q is

0,1,

- (CH₂)_mS(CH₂)₂-, wherein m = 1,2,

, wherein v is 1-3 and Y is two hydrogen atoms;

R³ and A may be taken together to form

, wherein, n = 0-1 and Y is two hydrogen atoms;

R⁹ is H, C₁-C₃ alkyl;

R⁵ is H, C₁-C₃ alkyl

In a more preferred embodiment, the above-described process provides intermediate compounds of formula (II) wherein: R⁵, R⁹, R¹⁶, R¹⁷ and R¹⁸ are H;

R¹¹, R¹², and R¹⁴ are H or CH₃;

R¹⁵ is H, C₁-C₄ alkyl, phenyl, benzyl, or phenyl-(C₂-C₄)alkyl; and

R³ is H or C₁-C₃ alkyl.

The above-described process specifically provides an intermediate compounds of formula (II) wherein: Y is phthalyl;

p is 0;

R¹⁹ is ;

R⁵, R⁹, R¹⁷, R¹⁵,R¹¹, R¹², R¹⁴ are H;

R² is C₂H₅;

R³ is CH₃; and

A is -(CH₂)₃-.

This invention also provides intermediate compounds useful in the claimed processes for the preparation of compounds of formula (I). Said intermediate compounds have formulae:

wherein:

Y is H, phthalyl, t-BOC, CBZ, t-BOCNH-C (=Nt- BOC)-, CBZ-NH-C(=NCBZ)-, Tos-NH-C(=NH)-, CF₃C(=O)-;

Z is H, t-butyl, benzyl, alkyl, t-BOC;

G is H, t-BOC, CBZ; R¹ is , wherein: p and p' are 0 or 1; R¹⁹ is a C₆-C₁₄ saturated, partially

saturated, or aromatic carbocyclic ring system or heterocyclic ring system composed of at least 1-3 heteroatoms selected from N, O, S; all these ring systems may be optionally substituted with 0-2 R⁷;

R¹⁷ and R¹⁶ are independently selected from the group: hydrogen;

C₁-C₄ alkyl, optionally substituted with halogen;

C₁-C₂ alkoxy;

benzyl;

R¹⁵ and R¹⁸ are independently selected from the group: hydrogen,

C₁-C₈ alkyl substituted with 0-2 R⁸, C₂-C₈ alkenyl substituted with 0-2 R⁸, C₂-C₈ alkynyl substituted with 0-2 R⁸,

C₃-C₈ cycloalkyl substituted with 0-2

R⁸,

C₆-C₁₀ bicycloalkyl substituted with

0-2 R⁸ aryl substituted with 0-2 R¹³, a heterocylic ring system composed of 5-10 atoms including 1-3 nitrogen, oxygen, or sulfur heteroatoms,

optionally substituted with 0-2 R¹³;

R¹⁵ and R¹⁷ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³; R¹⁸ and R¹⁶ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁵ and R¹⁴ can alternatively join to form a 5-8 membered carbocyclic ring

substituted with 0-2 R¹³, when R¹⁷ is H;

R⁷ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀

arylalkyl, C₁-C₄ alkoxy, -CO2R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R²°, -C(=O)R²⁰,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl optionally substituted with -NR²⁰R²¹;

R⁸ is independently selected at each

occurrence from the group:

=O, F, Cl, Br, I, -CF₃, -CN, -CO₂R²⁰, -C(=O)NR²⁰R²¹, -CH₂OR²⁰, -OC(=O)R20,

-CH₂NR²⁰R²¹, -NR²⁰R²¹;

R¹³ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀ arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆ cycloalkoxy, -OC(=O)R20, -C(=O)R20, - OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl (substituted with -NR²⁰R²¹);

R²⁰ is independently selected at each

occurrence from the group: H, C₁-C₇ alkyl, aryl, -(C₁-C₆

alkyl) aryl, or C₃-C₆ alkoxyalkyl;

R²¹ is independently selected at each

occurrence from the group:

H, C₁-C₄ alkyl, or benzyl;

R¹¹ is H or C₁-C₈ alkyl; R¹² is H or C₁-C₈ alkyl;

R¹⁴ is H or C₁-C₈ alkyl;

R² is H, C₁-C₈ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₁-C₆ cycloalkylethyl, phenyl, phenylmethyl, CH₂OH, CH₂SH,

CH₂OCH₃, CH₂SCH₃, CH₂CH₂SCH₃, (CH₂)_sNH₂, (CH₂)_sNHC(=NH) (NH₂), (CH₂)_sNHR²¹, wherein s = 3-5; R¹² and R² can be taken together to form-(CH₂)_t- , wherein t = 2-4, or -CH₂SC(CH₃)₂-;

R³ is H or C₁-C₈ alkyl;

A is selected from the group:

-(C₁-C₇ alkyl)-. , wherein q is 0,1, , wherein q is 0,1,

, wherein v is

0-3,

-(CH₂)_mO-(C₁-C₄ alkyl)-, wherein m = 1,2,

-(CH₂)_mS-(C₁-C₄ alkyl)-, wherein m - 1,2;

R³ and A may also be taken together to form , wherein n = 0-1 ;

R⁹ is H, C₁-C₈ alkyl; R⁵ is H, C₁-C₈ alkyl; and

R²⁵ is H or benzyl.

Preferred intermediate compounds of formulae III and IV are those wherein:

Y is H, phthalyl, CBZ, CBZ-NH-C(=NCBZ)-,

Tos-NH-C(=NH)-, CF₃C(=O)-;

Z is H, t-butyl;

G is H, t-BOC;

R¹⁹ is selected from:

, , ,

or

; R¹⁵ and R¹⁸ are independently selected from H, C₁-C₄ alkyl, phenyl, benzyl, phenyl-(C₂-C₄) alkyl, C₁-C₄ alkoxy; R¹⁷ and R¹⁶ are independently H or C₁-C₄ alkyl;

R⁷ is H, C₁-C₈ alkyl, phenyl, halogen, or C₁-C₄

alkoxy;

R¹¹ is H or C₁-C₃ alkyl;

R¹² is H or CH₃;

A is C₁-C₇ alkyl.

, wherein q is 0,1, , wherein q is 0,1,

-(CH₂)_mS(CH₂)₂-, wherein m = 1,2,

, wherein v is 0-3,

R³ and A may be taken together to form , wherein n = 0-1;

R⁹ is H, C₁-C₃ alkyl; R⁵ is H, C₁-C₃ alkyl.

Most preferred intermediate compounds of formulae III and IV are those preferred compounds wherein:

R⁵, R⁹, R¹⁶, R¹⁷ and R¹⁸ are H; R¹¹, R¹², and R¹⁴ are H or CH₃;

R¹⁵ is H, C₁-C₄ alkyl, phenyl, benzyl, or phenyl-(C₂-C₄)alkyl; and R³ is H or C₁-C₃ alkyl. Specifically preferred compounds of formulae II and IV are those wherein:

Y is phthalyl;

p is 0;

_R19 is ;

R⁵, R⁹, R¹⁷, R¹⁵,Rⁿ, R¹², R¹⁴ are H;

R² is C₂H₅;

R³ is CH₃; and

A is -(CH₂)₃-.

The compounds herein described may have

asymmetric centers. Unless otherwise indicated, all chiral, diastereomeric and racemic forms are included in the present invention. Many geometric isomers of olefins, C=N double bonds, and the like can also be present in the compounds described herein, and all such stable isomers are contemplated in the present invention. Two distinct isomers (cis and trans) of the peptide bond are known to occur; both can also be present in the compounds described herein, and all such stable isomers are contemplated in the present invention. Unless otherwise specifically noted, the L-isomer of the amino acid is the preferred stereomer of the present invention. The D and L-isomers of a particular amino acid are designated herein using the conventional 3-letter abbreviation of the amino acid, as indicated by the following examples: D-Leu, or L-Leu.

When any variable (for example, R¹ through R⁸, m, n, p, X, Y, etc.) occurs more than one time in any constituent or in any formula, its definition on each occurrence is independent of its definition at every other occurrence. Also, combinations of substituents and/or variables are permissible only if such

combinations result in stable compounds.

As used herein, "alkyl" is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms; "alkoxy" represents an alkyl group of indicated number of carbon atoms attached through an oxygen bridge; "cycloalkyl" is intended to include saturated ring groups, such as cyclopropyl,

cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; and "biycloalkyl" is intended to include saturated bicyclic ring groups such as

[3.3.0]bicyclooctane, [4.3.0]bicyclononane,

[4.4.0]bicyclodecane (decalin), [2.2.2]bicyclooctane, and so forth. "Alkenyl" is intended to include hydrocarbon chains of either a straight or branched configuration and one or more unsaturated carbon-carbon bonds which may occur in any stable point along the chain, such as ethenyl, propenyl and the like; and "alkynyl" is intended to include hydrocarbon chains of either a straight or branched configuration and one or more triple carbon-carbon bonds which may occur in any stable point along the chain, such as ethynyl,

propynyl and the like. "Halo" or "halogen" as used herein refers to fluoro, chloro, bromo and iodo; and "counterion" is used to represent a small, negatively charged species such as chloride, bromide, hydroxide, acetate, sulfate and the like.

As used herein, "aryl" is intended to mean phenyl or naphthyl; "carbocyclic" is intended to mean any stable 5- to 7- membered monocyclic or bicyclic or 7- to 14-membered bicyclic or tricyclic carbon ring, any of which may be saturated, partially unsaturated, or aromatic. Examples of such carbocyles include, but are not limited to cyclopentyl, cyclohexyl, phenyl, biphenyl, naphthyl, indanyl or tetrahydronaphthyl (tetralin).

As used herein, the term "heterocycle" or

"heterocyclic ring system" is intended to mean a stable 5- to 7- membered monocyclic or bicyclic or 7- to 10-membered bicyclic heterocyclic ring which may be saturated, partially unsaturated, or aromatic, and which consists of carbon atoms and from 1 to 3

heteroatoms selected from the group consisting of N, O and S and wherein the nitrogen and sulfur heteroatoms may optionally be oxidized, and the nitrogen may optionally be quaternized, and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The heterocyclic ring may be attached to its pendant group at any heteroatom or carbon atom which results in a stable structure. The heterocyclic rings described herein may be substituted on carbon or on a nitrogen atom if the resulting compound is stable. Examples of such heterocycles include, but are not limited to, pyridyl, pyrimidinyl, furanyl, thienyl, pyrolyl, pyrazolyl, imidazolyl, tetrazolyl, benzofuranyl, benzothiophenyl, indolyl, indolenyl, quinolinyl, isoquinolinyl or benzimidazolyl, piperidinyl, 4-piperidonyl,

pyrrolidinyl, 2-pyrrolidonyl, pyrolinyl,

tetrahydrofuranyl, tetrahydroquinolinyl,

tetrahydroisoquinolinyl, decahydroquinolinyl or octahydroisoquinolinyl.

By "stable compound" or "stable structure" is meant herein a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into an efficacious therapeutic agent. The term "substituted", as used herein, means that one or more hydrogen on the designated atom is replaced with a selection from the indicated group, provided that the designated atom's normal valency is not exceeded, and that the substitution results in a stable compound.

As used herein, the term "amine protecting group" means any group known in the art of organic synthesis for the protection of amine groups. Such amine protecting groups include those listed in

Greene, "Protective Groups in Organic Synthesis" John Wiley & Sons, New York (1981) and "The Peptides:

Analysis, Sythesis, Biology, Vol. 3, Academic Press, New York (1981), the disclosure of which is hereby incorporated by reference. Any amine protecting group known in the art can be used. Examples of amine protecting groups include, but are not limited to, the following: 1) acyl types such as formyl,

trifluoroacetyl, phthalyl, and p-toluenesulfonyl; 2) aromatic carbamate types such as benzyloxycarbonyl (Cbz) and substituted benzyloxycarbonyls, 1-(p-biphenyl)-1-methylethoxycarbonyl, and

9-fluorenylmethyloxycarbonyl (Fmoc); 3) aliphatic carbamate types such as tert-butyloxycarbonyl (Boc), ethoxycarbonyl, diisopropylmethoxycarbonyl, and allyloxycarbonyl; 4) cyclic alkyl carbamate types such as cyclopentyloxycarbonyl and adamantyloxycarbonyl; 5) alkyl types such as triphenylmethyl and benzyl; 6) trialkylsilane such as trimethylsilane; and 7) thiol containing types such as phenylthiocarbonyl and dithiasuccinoyl.

As used herein, "pharmaceutically acceptable salts and prodrugs" refer to derivatives of the disclosed compounds that are modified by making acid or base salts, or by modifying functional groups present in the compounds in such a way that the modifications are cleaved, either in routine

manipulation or in vivo, to the parent compounds.

Examples include, but are not limited to: mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; esters of carboxylates; acetate, formate and benzoate derivatives of alcohols and amines; and the like.

Pharmaceutically acceptable salts of the

compounds of the invention can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in

Remington's Pharmaceutical Sciences, 17th ed., Mack

Publishing Company, Easton, PA, 1985, p. 1418, the disclosure of which is hereby incorporated by

reference.

The term "amino acid" as used herein means an organic compound containing both a basic amino group and an acidic carboxyl group. Included within this term are modified and unusual amino acids, such as those disclosed in, for example, Roberts and Vellaccio (1983) The Peptides, 5: 342-429, the teaching of which is hereby incorporated by reference.

The term "amino acid residue" as used herein means that portion of an amino acid (as defined herein) that is present in a peptide or pseudopeptide. The term "peptide" as used herein means a linear compound that consists of two or more amino acids (as defined herein) that are linked by means of peptide or pseudopeptide bonds.

Synthesis The following abbreviations are used herein:

D-Abu D-2-aminobutyric acid

β-Ala or

bAla 3-aminopropionic acid

Boc t-butyloxycarbonyl

Boc-iodo-Mamb t-butyloxycarbonyl-3-aminomethyl-4-iodo- benzoic acid

Boc-Mamb t-butyloxycarbonyl-3-aminomethylbenzoic acid

Boc-ON [2-(tert-butyloxycarbonyloxylimino)-2- phenylacetonitrile

Cl₂Bzl dichlorobenzyl

CBZ Carbobenzyloxy

DCC dicyclohexylcarbodiimide

DIEA diisopropylethylamine

di-NMeOrn N-αMe-N-γMe-ornithine

DMAP 4-dimethylaminopyridine

HBTU 2-(1H-Benzotriazol-1-yl)-1,1,3,3- tetramethyluronium

hexafluorophosphate

NMeArg or

MeArg α-N-methyl arginine

NMeAmf N-Methylaminomethylphenylalanine

NMeAsp α-N-methyl aspartic acid

NMeGly or

MeGly N-methyl glycine

NMe-Mamb N-methyl-3-aminomethylbenzoic acid NMM N-methylmorpholine

OcHex O-cyclohexyl OBzl O-benzyl

TBTU 2-(1H-Benzotriazol-1-yl)-1,1,3,3- tetramethyluronium

tetrafluoroborate

Tos tosyl

The following conventional three-letter amino acid abbreviations are used herein; the conventional one-letter amino acid abbreviations are not used herein:

Ala = alanine

Arg = arginine

Asn = asparagine

Asp = aspartic acid

Cys = cysteine

Gln = glutamine

Glu = glutamic acid

Gly = glycine

His = histidine

Ile = isoleucine

Leu = leucine

Lys = lysine

Met = methionine

Nle = norleucine

Orn = ornithine

Phe = phenylalanine

Phg = phenylglycine

Pro = proline

Ser = serine

Thr = threonine

Trp = tryptophan

Tyr = tyrosine

Val = valine The present invention provides a process for the synthesis of compounds of formula (I). The provided process is accomplished using inexpensive, simple starting materials. The overall process is novel: it utilizes novel reaction steps, novel reaction

sequences, and novel reaction intermediates. In practicing the provided invention, knowledge of a number of standard techniques known to those in the art is required. The following discussion and

references are offered to provide such knowledge.

Generally, peptides are elongated by deprotecting the α-amine of the C-terminal residue and coupling the next suitably protected amino acid through a peptide linkage using the methods described. This deprotection and coupling procedure is repeated until the desired sequence is obtained. This coupling can be performed with the constituent amino acids in a stepwise fashion, or condensation of fragments (two to several amino acids), or combination of both

processes, according to the method originally

described by Merrifield, J. Am. Chem. Soc, 85, 2149-2154 (1963), "The Peptides: Analysis, Synthesis,

Biology, Vol. 1, 2, 3, 5, and 9, Academic Press, New York, (1980-1987); Bodanszky, "Peptide Chemistry: A

Practical Textbook", Springer-Verlag, New York (1988); and Bodanszky et al. "The Practice of Peptide

Sythesis" Springer-Verlag, New York (1984), the disclosures of which are hereby incorporated by reference.

The coupling of two amino acid derivatives, an amino acid and a peptide, two peptide fragments, or the cyclization of a peptide can be carried out using standard coupling procedures such as the azide method, mixed carbonic acid anhydride (isobutyl chloroformate) method, carbodiimide (dicyclohexylcarbodiimide, diisopropylcarbodiimide, or water-soluble

carbodiimides) method, active ester (p-nitrophenyl ester, N-hydroxysuccinic imido ester) method. Woodward reagent K method, carbonyldiimidazole method,

phosphorus reagents such as BOP-Cl, or oxidation-reduction method. Some of these methods (especially the carbodiimide) can be enhanced by the addition of 1-hydroxybenzotriazole. These coupling reactions may be performed in either solution (liquid phase) or solid phase.

The functional groups of the constituent amino acids must be protected during the coupling reactions to avoid undesired bond formation. The protecting groups that can be used, methods of using them to protect amino acids, and methods to remove them are listed in Greene, "Protective Groups in Organic

Synthesis" John Wiley & Sons, New York (1981) and "The Peptides: Analysis, Sythesis, Biology, Vol. 3,

Academic Press, New York (1981), the disclosure of which is hereby incorporated by reference.

The α-carboxyl group of the C-terminal residue is usually protected by an ester that can be cleaved to give the carboxylic acid. These protecting groups include: 1) alkyl esters such as methyl and t-butyl, 2) aryl esters such as benzyl and substituted benzyl, or 3) esters which can be cleaved by mild base

treatment or mild reductive means such as

trichloroethyl and phenacyl esters. In the solid phase case, the C-terminal amino acid is attached to an insoluble carrier (usually polystyrene). These insoluble carriers contain a group which will react with the carboxyl group to form a bond which is stable to the elongation conditions but readily cleaved later. Examples of which are: oxime resin (DeGrado and Kaiser (1980) J. Org. Chem . 45, 1295-1300) chloro or bromomethyl resin, hydroxymethyl resin, and

aminomethyl resin. Many of these resins are

commercially available with the desired C-terminal amino acid already incorporated.

The α-amino group of each amino acid must be protected. Any protecting group known in the art can be used. Examples of these are: 1) acyl types such as formyl, trifluoroacetyl, phthalyl, and p-toluenesulfonyl; 2) aromatic carbamate types such as benzyloxycarbonyl (Cbz) and substituted

benzyloxycarbonyls, 1-(p-biphenyl)-1-methylethoxycarbonyl, and 9-fluorenylmethyloxycarbonyl (Fmoc); 3) aliphatic carbamate types such as tert-butyloxycarbonyl (Boc), ethoxycarbonyl,

diisopropylmethoxycarbonyl, and allyloxycarbonyl; 4) cyclic alkyl carbamate types such as

cyclopentyloxycarbonyl and adamantyloxycarbonyl; 5) alkyl types such as triphenylmethyl and benzyl; 6) trialkylsilane such as trimethylsilane; and 7) thiol containing types such as phenylthiocarbonyl and dithiasuccinoyl. The preferred etamino protecting group is either Cbz, Boc or Fmoc. Many amino acid derivatives suitably protected for peptide synthesis are commercially available.

The α-amino protecting group is cleaved prior to the coupling of the next amino acid. When the Cbz group is used, the reagents of choice are

hydrogenation conditions using hydrogen at atmospheric pressure or in a Parr apparatus at elevated hydrogen pressure, or cyclohexene or ammonium formate over palladium, palladium hydroxide on charcoal or platinum oxide in methanol, ethanol or tetrahydrofuran, or combination of these solvents (P. N. Rylander,

Hydrogenation Methods, Acedemic Press, 1985). When the Boc group is used, the methods of choice are trifluoroacetic acid, neat or in dichloromethane, or HCl in dioxane. The resulting ammonium salt is then neutralized either prior to the coupling or in situ with basic solutions such as aqueous buffers, or tertiary amines in dichloromethane or

dimethylformamide. When the Fmoc group is used, the reagents of choice are piperidine or substituted piperidines in dimethylformamide, but any secondary amine or aqueous basic solutions can be used. The deprotection is carried out at a temperature between 0°C and room temperature.

Any of the amino acids bearing side chain

functionalities must be protected during the

preparation of the peptide using any of the above-identified groups. Those skilled in the art will appreciate that the selection and use of appropriate protecting groups for these side chain functionalities will depend upon the amino acid and presence of other protecting groups in the peptide. The selection of such a protecting group is important in that it must not be removed during the deprotection and coupling of the α-amino group.

For example, when Cbz is chosen for the amine protection the following protecting groups are

acceptable: p-toluenesulfonyl (tosyl) moieties for arginine; t-butyloxycarbonyl, phthalyl, or tosyl for lysine or ornithine; alkyl esters such as cyclopentyl for glutamic and aspartic acids; alkyl ethers for serine and threonine; and the indole of tryptophan can either be left unprotected or protected with a formyl group.

When Boc is chosen for the α-amine protection the following protecting groups are acceptable: p-toluenesulfonyl (tosyl) moieties and nitro for arginine; benzyloxycarbonyl, substituted

benzyloxycarbonyls, or tosyl for lysine; benzyl or alkyl esters such as cyclopentyl for glutamic and aspartic acids; benzyl ethers for serine and

threonine; benzyl ethers, substituted benzyl ethers or 2-bromobenzyloxycarbonyl for tyrosine; p-methylbenzyl, p-methoxybenzyl, acetamidomethyl, benzyl, or t-butylsulfonyl for cysteine; and the indole of

tryptophan can either be left unprotected or protected with a formyl group.

When Fmoc is chosen for the α-amine protection usually tert-butyl based protecting groups are

acceptable. For instance, Boc can be used for lysine, tert-butyl ether for serine, threonine and tyrosine, and tert-butyl ester for glutamic and aspartic acids.

Once the elongation and cyclization of the peptide is completed all of the protecting groups are removed. For the liquid phase synthesis the

protecting groups are removed in the manner dictated by the choice of protecting groups. These procedures are well known to those skilled in the art.

Unusual amino acids used in this invention can be synthesized by standard methods familiar to those skilled in the art ("The Peptides: Analysis, Sythesis, Biology, Vol. 5, pp. 342-449, Academic Press, New York (1981)). N-Alkyl amino acids can be prepared using proceedures described in previously (Cheung et al., (1977) Can . J. Chem . 55, 906; Freidinger et all, (1982) J. Org. Chem . 48, 77 (1982)), which are incorporated here by reference.

The process of the present invention utilizes the general methods described above along with the novel methods described below to prepare the compounds of Formula (I).

The process of the present invention begins with the sequence of steps shown in Scheme 1. In Step 1 of the process, a compound of formula (1) is reacted with an appropriate protecting group to give protected amine (2). The compound of formula (2) wherein Y is an amine protecting group, such as t-Boc, acyl, phthalyl, or other suitable group previously

described, can be prepared from an appropriately substituted α-amino acid by complexing the α-amine and carboxylic acid with a copper salt, in water, an alcohol, or dioxane, or combination of these solvents, and protecting the remote amine with a protecting group such as t-butyloxycarbonyl, acyl, phthalyl or another previously described protecting group. The preferred procedure for the preparation of compound (2) wherein Y is phthalyl, uses copper sulfate in water, and carbethoxyphthalimide as described in the procedure M. Bodanszky, M. Ondetti, C. Birkhime, and P. Thomas, "J. of American Chemical Society, 86, 4452, 1964".

In Step 2 of the process, the protected compound (3) is prepared by reacting amine (2) with any of the previously described amine protecting groups

precursors. The preferred protecting group is Cbz. Thus, reaction of amine compound (2) and benzyl chloroformate in 1,4-dioxane and water with sodium hydroxide as the acid scavenger at ambient temperature affords compound (3) wherein X is Cbz. This is shown in Scheme 1.

In Step 3 of the process, the oxazolidinone compound (4) is prepared, as shown in Scheme 1, by the condensation of an appropriately substituted aldehyde, such as formaldehyde, acetaldehyde, benzaldehyde, C₃-C₈ alkyl and branched alkyl aldehydes or aldehyde surrogates such as trioxane, dimethoxymethane or higher alkyl acetals, in a solvent like benzene, toluene, N,N-dimethylformamide, or dioxane with an acid catalyst such as p-toluenesulfonic acid,

hydrochloric acid, or trifluoroacetic acid at a temperature between 50°-150°C with a dean stark trap, molecular sieves, magnesium sulfate or other drying agent. The preferred procedure for the preparation of compound (4) wherein R²² is H, X is CBZ and Y is phthalyl, involves condensation of compound (3) wherein X is Cbz and Y is phthalyl with

paraformaldehyde or trioxane, and p-toluenesulfonic acid in toluene, or hydrogen chloride in dioxane, at reflux temperature with a dean stark trap. Other methods and reagents capable of affecting this

transformation are described in R. M. Freidinger, J.S. Hinkle, D. S. Perlow, B. H. Arison, J. Org. Chem., 1983, 48 , 77-81, Dov Ben-Ishai, JACS, 1957, 79, 5736, and all references contained therein.

In Step 4 of the process, as shown in Scheme 1, N-α-alkyl compound (5) is prepared by reduction of oxazolidinone (4) with triethylsilane and an acid such as trifluoroacetic acid in solvents such as methylene chloride or chloroform between -25° and 60°C. The preferred procedure for the preparation of compound (5) wherein X is Cbz, R²² is H and Y is phthalyl, from the corresponding compound (4) utilizes triethylsilane with trifluoroacetic acid in chloroform at ambient temperature to reflux temperature of the solvent.

Scheme 2 shows Steps 5-8 of the process of this invention. In Step 5, the dipeptide (6) is prepared by coupling amino acid (5) with an appropriately substituted carboxy protected amino acid, (AA) . Step 5 utilizes any of the several amide bond forming reactions described previously. The preferred method of Step 5 for the preparation of the compound of formula (6) wherein Z is t-butyl alkyl and X is Cbz is via reaction of the corresponding carboxylic acid (5) with glycine t-butyl ester, in the presence of the water soluble carbodiimde, 1-(3- dimthethylaminopropyl)-3-ethylcarbodiimide

hydrocloride, in the solvent methylene chloride, with N-methylmorpholine as the acid scavenger, at ambient temperature; or via reaction with isobutylchloroformate and N-methylmorpholine in tetrahydrofuran at -30° to 0° temperature.

In Step 6, the N-α-alkyl dipeptide (7) is

prepared by deprotection of the corresponding compound of formula (6) using the appropriate conditions for removal of the selected protecting group, as shown in Scheme 2. For example, for compounds of formula (6) wherein X is Cbz, one may use any of the many

hydrogentation methods well known in the literature, (see: P. N. Rylander, Hydrogenation Methods, Acedemic Press, 1985). Such methods include: catalytic

reduction with hydrogen over platinum oxide; and cyclohexene, ammonium formate or catalytic reduction at elevated hydrogen pressure over palladium on charcoal, in an appropriate solvent such as methanol or ethanol. The preferred method for the preparation of compound (7) wherein Z is t-butyl alkyl, involves hydrogenation of compound (6) wherein X is Cbz with 10% palladium on charcoal and ammonium formate, in an alcohol solvent, at a temperature between ambient temperature and 70°. Alternatively, the reaction may be carried out with 10% palladium on charcoal at elevated hydrogen pressure, in an alcohol solvent.

Step 7 of the process involves preparation of tripeptide (10) by coupling of an appropriately substituted N-α protected amino acid compound of formula (22) with the N-α-alkyl dipeptide compound (7). Compounds of formula (22) are commercially available (Sigma, BACHEM). Step 7 may be accomplished using any of the previously described methods for forming amide bonds. For Step 7, the preferred method to prepare compound (10) wherein X is Cbz, R³ is alkyl, and Z is t-butyl alkyl, is to activate the N-α-Cbz protected amino acid of the corresponding compound of formula (22) with O-benzotriazol-1-yl- N,N,N',N'-tetramethylurion hexafluorophosphate, or a carbodiimide and 1-hydroxybenzotriazole in the

presence of a compound of formula (7) wherein R³ is alkyl Z is t-butyl alkyl, and Y is a protecting group, in methylene chloride, at ambient temperature.

In Step 8, compound (11) is prepared by

hydrogenation of the N-α-Cbz-protected tripeptide,

(10), using conditions outlined above. The preferred reduction methods for preparation of a compound of formula (11) wherein Z is t-butyl alkyl, from compound (10) wherein X is Cbz, include: 10% palladium on charcoal and ammonium formate or cyclohexene, in an alcohol solvent, over a temperature range between ambient temperature and 70°C, or 10% palladium on charcoal at elvated hydrogen pressure, in an alcohol solvent.

Steps 9-11 of the process of this invention are shown in Scheme 3. In Step 9, the fully elaborated protected linear peptide compound, (15), is prepared by coupling the carboxylic acid compound, (14), and the amino tripeptide compound, (11). This step may be carried out using any of the previously described methods for forming amide bonds. The preferred coupling method for the preparation of the linear peptide of formula (15) wherein Z is t-butyl alkyl and G is t-Boc, from the amino compound (11) wherein Z is t-butyl alkyl and the carboxylic acid compound of formula (14) wherein G is t-Boc, utilizes 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride or O-benzotriazol-1-yl-N,N,N',N'-tetramethylurion hexafluorophosphate carbonyldiimiazole,

hydroxysuccinate ester or isobutylchloroformate and 1-hydroxybentriazole with N-methylmorpholine in N,N-dimethylformamide or acetonitrile at ambient

temperature.

In Step 10, the free amino acid peptide

compound, (16), is prepared by the deprotection of compound (15). For example, deprotection of (15) wherein Z is t-butyl alkyl and G is t-Boc may be accomplished using any of the variety of methods well known in the literature for the deprotection of t-butyl esters and t-Boc groups. Such methods include: hydrogen chloride in dioxane or ethyl acetate; and trifluoroacetic acid neat or in methylene chloride, chloroform, ether, or toluene. The preferred method to prepare the free amino acid compound, (16), by deprotection of compound (15) wherein G is t-Boc and Y is t-butyl alkyl, utilizes trifluoroacetic acid in methylene chloride or hydrogen chloride in dioxane, at ambient temperature.

In Step 11, the cyclic compound, (17), is

prepared by cyclization of the linear pentapeptide compound, (16). This Step may be accomplished using any of the variety of amide bond forming reactions well known in the literature, as previously described. Alternatively, the cyclization step may be carried out using macrocyclization techniques. The preferred cyclization methods for the preparation of compounds of formula (17) from the linear compound, (16), utilizes a carbodiimide such as 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, dicyclohexylcarbodiimide, or O-benzotriazol-1-yl-N,N,N',N'-tetramethylurion

hexafluorophosphate and 1-hydroxybentriazole with N-methylmorpholine, in a solvent such as N,N-dimethylformamide or acetonitrile, at ambient

temperature.

Steps 12-14 of the process of this invention are shown in Scheme 4. In Step 12, the carboxylic acid,

(18), is prepared from the corresponding compound of formula (17) wherein R²⁵ is benzyl by reduction of the ester using methods any of the previously described methods. The preferred methods for the reduction of the protected compound (17) wherein R²⁵ is benzyl include: 10% palladium on charcoal and ammonium formate or cyclohexene in ethanol, methanol,

tetrahydrofuran, or combinations of these solvents, over a temperature range between ambient temperature and 70°.

In Step 13, the amino compound of formula (19) is prepared by removal of the protecting group, Y, of (18) via methods appropriate for removing the selected protecting group, Y. The preferred methods for preparation of the amino compound (19) from the protected compound (18) wherein Y is phthalyl, utilize hydrazine, or. methyl amine or other lower alkyl amines in solvents such as water, methanol, ethanol or combination of these solvents, at a temperature between ambient temperature and 80°. [M. Ghazala, et al, J. Med. Chem., 29(7), 1263-1269 (1986), W. M.

Bryan, J. Org. Chem., 51(7), 3371-72, (1986), J. T. Doi, G. W. Luehr, Tetrahedron Letters, 26(50), 6143-6146 (1985)]. An alternative method utilizes sodium borohydride as the reductive agent. [J. O. Osby, M. G. Martin, B. Ganem, Tetrahedron Letters, 25(20), 2093-6, (1984)].

In Step 14 of the process, the compound of formula (I) is prepared. The preparation is effected by reacting the amine compound, (19), with any of the variety of reagents capable of converting an amine to a guanidine compound or a protected guanidine.

Suitable reagents include: S-methyl and O-methyl isoureas, guanyl-3, 5-dimethylpyrazole, cyanamide, formamidine sulfonic acid, bis-carbamate protected s-alkyl isoureas, "The Peptide" vol 2, 169-175,

Garigipat et al. Tetrahedron Letters 31, 1969 (1990), Kim et al. Tetrahedron Letters 29, 3183 (1988), Miller and Bischoff, Synthesis 777,(1986), Delle Monache EPO330629A2 (1989) and Bernard et al. Can. J. Chem. 36,1541 (1958). The preferred method for the

conversion of the amino compound (19) to the guanidine compound (I) utilizes formamidine sulfonic acid and N,N-dimethylaminopyridine, in solvents such as water, methanol, ethanol, dioxane or combination of these solvents at ambient temperature to reflux temperature of the solvent.

The preparation of intermediate compound (14) is shown in Scheme 5. The pseudodipeptide (14) is prepared by coupling the amino carboxylic acid

compound of formula (13) or formula (13A), with the activated carboxylic acid of an appropriately

substituted N-α protected amino acid of formula (21) wherein G is a protecting group such as t-Boc, using any of the amide bond forming reactions previously described. The preferred method for preparing the carboxylic acid compound, (14), wherein R¹ is phenyl, is by reaction of the free amino acid compound, (13) wherein R¹ is phenyl, with a carboxylic acid, (21), activated with N,N'-carbonyldiimidazole, in the solvent N,N-dimethylformamide, at ambient temperature. Alternatively, the carboxylic acid can be activated as the N-hyroxysuccinate ester in a solvent such as methylene chloride or N,N-dimethylformamide.

The amino carboxylic acid compound of formula (13) or formula (13A) can be purchased or can be prepared by reduction of the appropriately substituted cyano carboxylic acid compound (12) by methods well known in the literature for reducing cyano groups, as described in Tett . Lett . , 4393 (1975); Modern

Synthetic Reactions, H.O. House (1972); or Harting et al. J. Am . Chem . Soc , 50: 3370 (1928). The preferred method for preparing the amino acid (13), wherein R¹ is phenyl from (12) involves reductive hydrogenation at elevated hydrogen pressure, with 10% palladium on charcoal in an alcohol solvent like ethanol between ambient temperature and 60°C. For example, reduction of 3- or 4-cyanobenzoic acid, which is a compound of formula (12) wherein R¹ is phenyl, under these

conditions affords the corresponding benzyl amine of formula (13).

Other analogues of compounds of formula (13) and (13A) may be prepared by any of a number of methods well known in the literature or as described in the following schemes. For example, the N-alkylated compound of formula (23) can be prepared according to standard procedures, for example, Olsen, J. Org. Chem . (1970) 35: 1912). This compound may also be prepared as shown in Scheme 6.

Schemes 7-10 show a number of routes to

intermediate compounds of formula (24). Compound (24) falls within general formula (13) and is useful for the synthesis of compounds of formula (14). Scheme 7 details a method for the preparation of compounds of formula (24) wherein R²³ is CH₃, CH₂CH₃, CH₂CH₂CH₃, CH₂CH₂CH₂CH₃, CH(CH₃)2, C(CH₃)3, CH(CH₃)CH₂CH₃, benzyl, cyclopentyl, or cyclohexyl. Scheme 8 shows a route for the preparation of compounds of formula (24) wherein R²³ = CH₃, CH₂CH₂CH₂CH₃, or phenyl. Schemes 9 and 10 show routes for the preparation of compounds of formula (24) wherein R²³ = CH₃ or phenyl.

3-Aminophenylacetic acids. Formula (25), which is another compound of general formula (13) and is useful as an intermediate in the synthesis of the compounds of the invention is prepared using standard procedures, for example, as described in Collman and Groh (1982) J. Am . Chem . Soc , 104: 1391, and as shown below:

The 4, 5, and 6-Substituted 3-aminomethylbenzoic acid•HCl of formula (26), can be prepared using standard procedures, for example, as described in Felder et al Helv. Chim . Acta, 48: 259 (1965); de Diesbach Helv. Chim . Acta, 23: 1232 (1949); Truitt and Creagn J. Org. Chem . , 27: 1066 (1962); or Sekiya et al Chem . Pharm . Bull . , 11: 551 (1963), and as shown below. Such compounds fall within general formula (13) and are useful for the preparation of compounds of formula (14) as shown in Scheme 3.

Compounds such as 2-Aminomethylbenzoic acid-HCl, (27), and 2-aminomethylphenylacetic acid-HCl, (28), fall within general formula (13) and are useful as intermediates in the synthesis of the compounds of formula (14) as shown in Scheme 3. See Naito et al J. Antibiotics, 30: 698 (1977); or Young and Sweet J. Am . Chem . Soc , 80: 800 (1958), and as shown below:

Alternatives carbocylic residues for R¹ of the invention include aminoalkyl-naphthoic acid. Formula (29), and aminoalkyl-tetrahydronaphthoic acid. Formula (30). The synthesis of these intermediates is outlined below in Scheme 11:

Some other possible analogues for R¹ Formula (I) can be prepared according to a modification of standard procedures previously reported in the literature (Earnest, I., Kalvoda, J., Rihs, G., and Mutter, M., Tett. Lett., Vol. 31, No. 28, pp 4011-4014, 1990).

An alternative process for the preparation of compounds of formula (I) involves introduction of the guanidine residue at an earlier stage. In this process, a synthon bearing a guanidine residue, such as compound (9), or a synthon bearing a protected guanidine residue, such as compound (9A), is used instead of a compound of formula (5) in the process depicted in Scheme 2. Scheme 12 shows methods for the preparation of compounds of formula (9) and (9A). The amine compound Formula (8) can be prepared from the protected amine compound (5) wherein Y is phthalyl using methods previously discussed for the removal of a phthalyl group. The preferred method involves the use of hydrazine or methylamine, in a solvent such as ethanol, at a temperature between ambient temperature to reflux temperature of the solvent. The compound of formula (9) can be prepared from the amino compound (8), using any of the variety of methods previously described for converting an amine to a guanidine.

Alternatively, compound Formula (9A), can be prepared from the amino compound Formula (8), or compound

Formula 9 using any of the variety of methods in the literature that describe preparation of protected guanidines. The preferred methods for the preparation of the protected quanidine compound of formula (9A), are di-t-Boc S-methyl isothiourea or di-CBZ S-methyl isothiourea (Delle Monche, et al, EPO 0330629A2) in methanol or ethanol at tempertatures between ambient and reflux temperature of the solvent.

Utilization of (9) or (9A) in Scheme 2 would ultimately afford an intermediate such as (11A) or (11B):

Compounds (11) or (11B) could then be utilized in the processes described in Schemes 3-4 to provide, ultimately, compounds of formula (I)

Examples

All chemicals and solvents (reagent grade) were used as supplied from the vendors cited without further purification. t-Butyloxycarbonyl (Boc) amino acids and other starting amino acids may be obtained commercially from Bachem Inc., Bachem Biosciences Inc. (Philadelphia, PA), Advanced ChemTech (Louisville, KY), Peninsula Laboratories (Belmont, CA), or Sigma (St. Louis, MO). 2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) and TBTU were purchased from Advanced ChemTech.

N-methylmorpholine (NMM), m-cresol, D-2-aminobutyric acid (Abu), trimethylacetylchloride,

diisopropylethylamine (DIEA), 3-cyanobenzoic acid and [2-(tert-butyloxycarbonyloxylimino)-phenylacetonitrile] (Boc-ON) were purchased from

Aldrich Chemical Company. Dimethylformamide (DMF), ethyl acetate, chloroform (CHCl3), methanol (MeOH), pyridine and hydrochloric acid (HCl) were obtained from Baker. Acetonitrile, dichloromethane (DCM), acetic acid (HOAc), trifluoroacetic acid (TFA), ethyl ether, triethylamine, acetone, and magnesium sulfate were purchased from EM Science. Palladium on carbon catalyst (10% Pd) was purchased from Aldrich Chemical Company or Fluka Chemical Company. Absolute ethanol was obtained from Quantum Chemical Corporation.

Thin layer chromatography (TLC) was performed on

Silica Gel 60 F₂₅₄ TLC plates (layer thickness 0.2 mm) which were purchased from EM Separations. TLC visualization was accomplished using UV light, iodine, and/or ninhydrin spray. Melting points were

determined using a Thomas Hoover or Electrothermal 9200 melting point apparatus and are uncorrected. NMR spectra were recorded on a 300 MHz General Electric QE-300, Varian 300, or Varian 400 spectrometer. Fast atom bombardment mass spectrometry (FAB-MS) was performed on a VG Zab-E double-focusing mass

spectrometer using a Xenon FAB gun as the ion source or a Finnigan MAT 8230. Preparation of Intermediates

Preparation of 3-Aminomethylbenzoic acid•HCl 3-Cyanobenzoic acid (10.0 g, 68 mmol) was dissolved in

200 ml ethanol by heating in a 35-50ºC water bath.

Concentrated HCl (6.12 ml, 201 mmol) was added and the solution was transferred to a 500 ml nitrogen-flushed round bottom flask containing palladium on carbon catalyst (1.05 g, 10% Pd/C). The suspension was stirred under an atmosphere of hydrogen for 38 hours, filtered through a scintered glass funnel, and washed thoroughly with H₂O. The ethanol was removed under reduced pressure and the remaining aqueous layer, which contained a white solid, was diluted to 250 ml with additional H₂O. Ethyl ether (250 ml) was added and the suspension was transferred to a

separatory funnel. Upon vigorous shaking, all solids dissolved and the aqueous layer was then washed two times with ether, evaporated under reduced pressure to a volume of 150 ml, and lyophilized to give the title compound (3-aminomethylbenzoic acid-HCl) (8.10 g, 64%) as a beige solid. ¹H NMR (D₂O) 4.27 (s, 2H), 7.60 (t, 1H), 7.72 (d,1H), 8.06 (d, 2H).

Preparation of t-Butyloxycarbonyl-3-aminomethylbenzoic

Acid (Boc-Mamb)

The title compound was prepared according to a modification of standard procedures previously

reported in the literature (Itoh, Hagiwara, and Kamiya (1975) Tett . Lett . , 4393). 3-Aminomethylbenzoic acid (hydrochloride salt) (3.0 g, 16.0 mmol) was dissolved in 60 ml H₂O. To this was added a solution of Boc-ON (4.33 g, 17.6 mmol) in 60 ml acetone followed by triethylamine (5.56 ml, 39.9 mmol). The solution turned yellow and the pH was adjusted to 9 (wet pH paper) by adding an additional 1.0 ml (7.2 mmol) triethylamine. The solution was stirred overnight at room temperature at which time the acetone was removed under reduced pressure and the remaining aqueous layer was washed three times with ether. The aqueous layer was then acidified to pH 2 with 2N HCl and then extracted three times with ethyl acetate. The

combined organic layers were washed three times with H₂O, dried over anhydrous magnesium sulfate, and evaporated to dryness under reduced pressure. The material was recrystallized from ethyl acetate/ hexane to give two crops of the title compound (2.58 g, 64%) as an off-white solid, mp 123-125°C ; ¹H NMR (CDCl₃)

1.47 (s, 9 H), 4.38 (br s, 2 H), 4.95 (br s, 1H), 7.45 (t, 1H), 7.55 (d, 1H), 8.02 (d, 2H).

Preparation of 3-[1'-(t- butyloxycarbonyl)aminolethylbenzoic acid (BOC-MeMAMB)

3-Acetylbenzoic acid (0.50 g, 3 mmol),

hydroxylamine hydrochloride (0.70 g, 10 mmol) and pyridine (0.70 ml, 9 mmol) were refluxed in 10 ml ethanol, for 2 h. Reaction mixture was concentrated, residue triturated with water, filtered and dried.

Oxime was isolated as a white solid (0.51 g ; 94.4% yield). ¹HNMR (CD₃OD) 7.45-8.30 (m, 4H), 2.30 (s, 3H). MS (CH₄-CI) [M+H-O] = 164.

A solution of the oxime (0.51 g, 3 mmol) in ethanol, containing 10% Pd on carbon (1.5 g) and cone. HCl (0.25 ml, 3 mmol) was hydrogenated at 30 psi H₂ pressure in a Parr hydrogenator for 5 h. Catalyst was filtered and the filtrate concentrated. Residue was triturated with ether. The hydrochloride salt was isolated as a white solid (0.48 g ; 85.7% yield).

1HNMR (CD₃OD) 7.6-8.15 (m, 4H), 4.55(q, 1H), 1.70(s,

3H). MS [M+H] = 166.

The amine hydrochloride (0.40 g, 2 mmol) was dissolved in 15 ml water. A solution of BOC-ON (0.52 g, 2.1 mmol) in 15 ml acetone was added, followed by the addition of triethylamine (0.8 ml, 6 mmol).

Reaction was allowed to proceed for 20 h. The reaction mixture was concentrated and partitioned between ethyl acetate and water. Aqueous layer was acidified to pH 2 using 10% HCl solution. Product was extracted in ethyl acetate, which after the usual work up and

recrystallization from ethyl acetate/hexane, gave the title compound as a white solid (0.30 g ; 57% yield). m.p. 116-118° C.

1HNMR (CDCl₃) 7.35-8.2 (m, 4H), 4.6(bs, 1.5H), 1.50 (d,

3H), 1.40 (s, 9H). MS (NH3-CI) [M+NH₄] = 283.

Preparation of 3-[1'-(t-butyloxycarbonyl)amino]benzylbenzoic acid (BOC-PhMAMB)

A solution of 3-benzoylbenzoic acid (2.00 g, 9 mmol), hydroxylamine hydrochloride (2.00 g, 29 mmol) and pyridine (2.00 ml, 25 mmol) in ethanol was

refluxed for 12 h. After the usual extractive work up, white solid was obtained (2.41 g). The product still contained traces of pyridine, but was used in the next step without further purification.

The crude product (2.00 g, ~8 mmol) was

dissolved in 200 ml ethanol. 10% Pd-C (2.00 g) and con. HCl (1.3 ml, 16 mmol) were added. Reaction mixture was hydrogenated at 30 psi for 1 h. The catalyst was filtered and the reaction mixture

concentrated. Upon trituration of the residue with ether and drying under vacuum, amine hydrochloride was obtained as a white solid (2.12 g ; 97% yield). ¹HNMR (CD₃OD) 7.4-8.15 (m, 10H), 5.75(s, 1H). MS (CH₄-CI) [M+H-OH] = 211.

Amine hydrochloride (1.00 g, 4 mmol) was

converted to its BOC-derivative by a procedure similar to the methyl case. 0.60 g (48% yield) of the

recrystallized (from ethanol/hexane) title compound was obtained as a white solid, m.p. 190-192° C. ¹HNMR (CD₃OD) 7.2-8.0 (m, 10H), 5.90 (2s, 1H, 2 isomers), 1.40(s, 9H). MS (NH₃-CI) [M+NH₄-C₄H₈] = 289

Preparation of t-Butyloxycarbonyl-D-2-aminobutyric

Acid

D-2-aminobutyric acid (1.0 g, 9.70 mmol) was dissolved in 20 ml H₂O and a solution of Boc-ON (2.62 g, 10.6 mmol) in 20 ml acetone was added. A white precipitate formed which dissolved upon addition of triethylamine (3.37 ml, 24.2 mmol) to give a pale yellow solution (pH = 9, wet pH paper). The solution was stirred at room temperature overnight at which time the acetone was removed under reduced pressure. The remaining aqueous layer was extracted with ether three times, acidified to pH 2 with concentrated HCl, and then extracted with ethyl acetate three times. The combined organic layers were dried over anhydrous magnesium sulfate and evaporated under reduced

pressure to give t-butyloxycarbonyl-D-2-aminobutyric acid as an oil (2.05 g, greater than quantitative yield, contains solvent), which was used without further purification. ¹H NMR (CDCl₃) 0.98 (t, 3H), 1.45 (s, 9H), 1.73 (m, 1H), 1.90 (m, 1H), 4.29 (m, 1H), 5.05 (m, 1H).

Preparation of t-ButyIoxycarbonyl-3-aminophenylacetic

Acid A solution of 3-aminophenylacetic acid (Aldrich, 10 g, 66 mmol), di-tert-butyl dicarbonate (15.8 g, 72 mmol), and DIEA (8.6 g, 66 mmol) in 50 ml of

dichloromethane was stirred overnight at room

temperature. The reaction mixture was concentrated, partitioned between dichloromethane-H₂O, the water layer was separated, acidified to pH 3 with 1N HCl, and extracted with dichloromethane. The extracts were washed with H₂O, brine, dried over anhydrous sodium sulfate, and evaporated to dryness under reduced pressure. This material was purified by

recrystallization from heptane to provide the title compound (3.7 g, 22%) as a white solid, mp 105°C; ¹H NMR (CDCl₃) 7.35 (s, 1H), 7.25 (m, 3H), 6.95 (m, 1H), 6.60 (br s, 1H), 3.65 (s, 2H), 1.50 (s, 9H).

Preparation of Synthesis of 4-Chloro-3- aminomethylbenzoic Acid-ΗCl The title compound was prepared by modification of procedures previously reported in the literature (Felder et al (1965) Helv. Chim . Acta, 48: 259). To a solution of 4-chlorobenzoic acid (15.7 g, 100 mmol) in 150 ml of concentrated sulfuric acid was added N-hydroxymethyl dichloroacetamide (23.7 g, 150 mmol) in portions. The reaction mixture was stirred at room temperature for 2 days, poured onto 375 g of ice, stirred for 1 hour, the solid was collected by

filtration, and washed with H₂O. The moist solid was dissolved in 5% sodium bicarbonate solution, filtered, and acidified to pH 1 with concentrated HCl. The solid was collected by filtration, washed with H₂O, and air-dryed overnight to give 4-chloro-3-dichloroacetylaminomethylbenzoic acid (26.2 g, 89%) as a white powder. A suspension of 4-chloro-3-dichloroacetylaminomethylbenzoic acid (26.2 g, 88 mmol) in 45 ml of acetic acid, 150 ml of concentrated HCl, and 150 ml of H₂O was heated to reflux for 3 hours, filtered while hot, and allowed to cool to room temperature. The solid was collected by filtration, washed with ether, washed with acetone-ether, and air-dryed overnight to give the title compound (7.6 g, 39%) as off-white crystals, mp 278-9°C; ¹H NMR (D₆- DMSO) 13.40 (br s, 1H), 8.75 (br s, 3H), 8.20 (s, 1H), 7.95 (dd, 1H), 7.70 (d, 1H), 4.20 (br s, 2H).

Preparation of t-Butyloxycarbonyl-4-chloro-3- aminomethylbenzoic Acid

A suspension of 4-chloro-3-aminomethylbenzoic acid•HCl (6.7 g, 30 mmol) and triethylamine (9.3 g, 92 mmol) in 50 ml of H₂O, was added to a solution of Boc-ON (9.2 g, 38 mmol) in 50 ml of tetrahydrofuran cooled to 0°C. The reaction mixture was stirred at room temperature overnight, and the volatile compounds were removed by concentration under reduced pressure. The residue was diluted with H₂O, washed with ether, acidified to pH 3 with 1N HCl, and extracted with ethyl acetate. The extracts were washed with H₂O, brine, dried over anhydrous magnesium sulfate, and evaporated to dryness under reduced pressure. This material was triturated with ether-hexane to provide the title compound (7.4 g, 87%) as a white powder, mp 159°C (dec); ¹H NMR (D6~DMSO) 13.20 (br s, 1H) , 7.90 (s, 1H), 7.80 (dd, 1H), 7.60 (br s, 1H), 7.55 (d, 1H), 4.20 (br d, 2H), 1.40 (s, 9H). Preparation of 2-Aminomethylphenylacetic Acid d-Lactam The title compound was prepared by modification of procedures previously reported in the literature (Naito et al. (1977) J. Antibiotics, 30: 698). To an ice-cooled suspension of 2-indanone (10.8 g, 82 mmol) and azidotrimethylsilane (9.4 g, 82 mmol) in 115 ml of chloroform was added 25 ml of concentrated sulfuric acid at a rate to maintain the temperature between 30-40°C. After an additional 3 hours, the reaction mixture was poured onto ice, and the water layer was made basic with concentrated ammonium hydroxide. The chloroform layer was separated, washed with H₂O, brine, dried over anhydrous magnesium sulfate, and evaporated to dryness under reduced pressure. This material was purified by sublimination (145°C, < 1 mm), followed by recrystallization from benzene to give the title compound (5.4 g, 45%) as pale yellow crystals, mp 149-150°C; ¹H NMR (CDCl₃) 7.20 (m, 5H), 4.50 (s,

2H), 3.60 (s, 2H). Preparation of 2-Aminomethylphenylacetic Acid•HCl The title compound was prepared by modification of procedures previously reported in the literature (Naito et al. (1977) J. Antibiotics, 30: 698). A mixture of 2-aminomethylphenylacetic acid d-lactam (6.4 g, 44 mmol) and 21 ml of 6N HCl was heated to reflux for 4 hours. The reaction mixture was treated with activated carbon (Norit A), filtered, evaporated to dryness, and the residual oil triturated with acetone. Filtration provided the title compound (5.5 g, 62%) as colorless crystals, mp 168°C (dec); ¹H NMR (D₆-DMSO) 12.65 (br s, 1H), 8.35 (br s, 3H), 7.50 (m, 1H), 7.35 (m, 3H), 4.05 (ABq, 2H), 3.80 (s, 2H).

Preparation of 2-Aminomethylbenzoic Acid g-Lactam The title compound was prepared by modification of procedures previously reported in the literature (Danishefsky et al. (1975) J. Org. Chem . , 40: 796). A mixture of methyl o-toluate (45 g, 33 mol), N-bromosuccinimide (57 g, 32 mol), and dibenzoyl

peroxide (0.64 g) in 175 ml of carbon tetrachloride was heated to reflux for 4 hours. The cooled reaction mixture was filtered, evaporated to dryness under reduced pressure, dissolved in 250 ml of methanol, and concentrated ammonium hydroxide (75 ml, 1.11 mol) was added. The reaction mixture was heated to reflux for 5 hours, concentrated, filtered, and the solid washed with H₂O followed by ether. This material was purified by recrystallization from H₂O to give the title compound (11.0 g, 26%) as a white solid, mp 150°C; ¹H NMR (CDCl₃) 7.90 (d, 1H), 7.60 (t, 1H), 7.50 (t, 2H),

7.00 (br s, 1H), 4.50 (s, 2H).

Preparation of 2-Aminomethylbenzoic Acid•HCl The title compound was prepared using the

general procedure described above for 2-aminomethylphenylacetic acid•HCl. The lactam (3.5 g, 26 mmol) was converted to the title compound (2.4 g, 50%) as colorless crystals, mp 233°C (dec); ¹H NMR (D₆-DMSO) 13.40 (br s, 1H), 8.35 (br s, 3H), 8.05 (d,

1H), 7.60 (m, 3H), 4.35 (br s, 2H).

Preparation of 8-Amino-5,6,7,8-tetrahydro-2-naphthoic

Acid Hydrochloride (8)

Part A - A solution of 4-phenylbutyric acid (50.0 g, 0.3 mol) in ethanol (140 mL) with concentrated

sulfuric acid (0.53 mL) was stirred at reflux over 5 hours. The cooled solution was poured into ice water and extracted with ethyl acetate. The combined organic layers were backwashed with brine, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure to give 4-phenylbutyric acid ethyl ester (56.07 g, 0.29 mol, 97%) as a yellow liquid. ¹H NMR (CDCI₃) d 7.3-7.1 (m, 5H), 4.1 (q, 2H, J=7.1 Hz), 2.7 (t, 2H, J=7.7 Hz), 2.3 (t, 2H, J=7.5 Hz), 1.95 (quintet, 2H, J=7.5 Hz), 1.25 (t, 3H, J=7.1 Hz).

Part B - To a solution of aluminum chloride (153 g, 1.15 mol), and acetyl chloride (38.5 mL, 42.5 g, 0.54 mol) in dichloromethane (1500 mL) was added, dropwise, a solution of 4-phenylbutyric acid ethyl ester (50.0 g, 0.26 mol) in dichloromethane (500 mL). All was stirred at ambient temperature for 15 minutes. The solution was poured into cold concentrated

hydrochloric acid (2000 mL) and then extracted with dichloromethane. The combined organic layers were backwashed with brine, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure to give 4-acetylphenylbutyric acid ethyl ester (53.23 g, 0.23 mol, 88%) as a dark yellow liquid. ¹H NMR (CDCI₃) d 7.9 (d, 2H, J=8.1 Hz), 7.25 (d, 2H, J=8.4 Hz), 4.1 (q, 2H, J=7.1 Hz), 2.75 (t, 2H, J=7.6 Hz), 2.6 (s, 3H), 2.35 (t, 2H, J=7.6 Hz), 2.0 (quintet, 2H, J=7.5 Hz), 1.25 (t, 3H, J=7.1 Hz).

Part C -To a solution of 4-acetylphenylbutyric acid ethyl ester (50.0 g, 0.21 mol) in ethanol (1250 mL) was added, dropwise, a solution of sodium hydroxide

(50.0 g) in water (1250 mL). All was stirred at reflux over 4 hours. The solution was concentrated to half volume and then acidified to a pH equal to 1.0 using hydrochloric acid (IN). The resulting precipitate was collected and washed with water to give 4- acetylphenylbutyric acid (53.76 g, 0.26 mol, 99%) as a white solid, mp = 50-52°C; ¹H NMR (CDCl₃) d 7.9 (d, 2H, J=8.1 Hz), 7.25 (d, 2H, J=9.1 Hz), 2.75 (t, 2H, J=7.7 Hz), 2.6 (S, 3H), 2.4 (t, 2H, J=7.3 Hz), 2.0 (quintet, 2H, J=7.4 Hz).

Part D -To a solution of sodium hypochlorite (330 mL, 17.32 g, 0.234 mol) in a solution of sodium hydroxide (50%, 172 mL), warmed to 55°C, was added, portionwise as a solid, 4-acetylphenylbutyric acid (16.0 g, 0.078 mol) while keeping the temperature between 60-70°C. All was stirred at 55°C over 20 hours. The cooled solution was quenched by the dropwise addition of a solution of sodium bisulfite (25%, 330 mL). The mixture was then transferred to a beaker and acidified by the careful addition of concentrated hydrochloric acid. The resulting solid was collected, washed with water and dried, then triturated sequentially with chlorobutane and hexane to give 4-carboxyphenylbutyric acid (15.31 g, 0.074 mol, 95%) as a white solid, mp = 190-195°C; ¹H NMR (DMSO) d 12.55 (bs, 1H), 8.1 (s, 1H), 7.85 (d, 2H, J=8.1 Hz), 7.3 (d, 2H, J=8.1 Hz), 2.7 (t, 2H, J=7.5 Hz), 2.2 (t, 2H, J=7.4 Hz), 1.8 (quintet, 2H, J=7.5 Hz).

Part E - A mixture of 4-carboxyphenylbutyric acid (10.40 g, 0.05 mol), aluminum chloride (33.34 g, 0.25 mol) and sodium chloride (2.90 g, 0.05 mol) was heated with continual stirring to 190°C over 30 minutes. As the mixture cooled to 60°C, cold hydrochloric acid (1N, 250 mL) was carefully added. The mixture was extracted with dichloromethane. The combined organic layers were backwashed with dilute hydrochloric acid and water, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The resulting solid was triturated with chlorobutane to give 1-tetralon-7-carboxylic acid (9.59 g, 0.05 mol, 100%) as a brown solid, mp = 210-215°C; ¹H NMR (DMSO) d 8.4 (s, 1H), 8.1 (d, 2H, J=8.0 Hz), 7.5 (d, 1H, J=7.9 Hz), 3.0 (t, 2H, J=6.0 Hz), 2.65 (t, 2H, J=6.6 Hz), 2.1 (quintet, 2H, J=6.3 Hz).

Part F - A solution of 1-tetralon-7-carboxylic acid (1.0 g, 0.0053 mol) and sodium acetate (1.93 g, 0.024 mol) and hydroxylamine hydrochloride (1.11 g, 0.016 mol) in a mixture of methanol and water (1:1, 15 mL) was stirred at reflux over 4 hours. The mixture was cooled and then added was more water (50 mL). The solid was collected, washed with water and dried, then triturated with hexane to give 1-tetralonoxime-7-carboxylic acid (0.78 g, 0.0038 mol, 72%) as a white solid, mp = 205-215°C; ¹H NMR (DMSO) d 11.3 (s, 2H), 8.4 (s, 1H), 7.8 (d, 1H, J=7.7 Hz), 7.3 (d, 1H, J=7.7 Hz), 2.8 (t, 2H, J=5.9 Hz), 2.7 (d, 2H, J=6.6 Hz), 1.9-1.7 (m, 2H).

Part G - A mixture of 1-tetralonoxime-7-carboxylic acid (0.75 g, 0.0037 mol) in methanol (25 mL) with concentrated hydrochloric acid (0.54 mL, 0.20 g, 0.0056 mol) and palladium on carbon catalyst (0.10 g, 5% Pd/C) was shaken for 20 hours at ambient

temperature under an atmosphere of hydrogen (60 psi). The reaction mixture was filtered over Celite™ and washed with methanol. The filtrate was evaporated to dryness under reduced pressure and the residue was purified by flash chromatography using hexane: ethyl acetate::1:1 to give the racemic mixture of 8-amino-5,6,7,8-tetrahydro-2-naphthoic acid hydrochloride (0.225 g, 0.001 mol. 27%) as a white solid, mp = 289-291°C; ¹H NMR (DMSO) d 8.55 (bs, 3H), 8.2-8.1 (m, 1H), 7 . 85-7 . 8 (m, 1H) , 7 . 35-7 . 25 (m, 1H) , 4 . 5 (m, 1H) , 2 . 9-2 . 8 (m, 2H) , 2 . 1-1 . 9 (m, 3H) , 1 . 85-1 . 7 (m, 1H) .

Preparation of N-(BOC)-8-Aminomethyl-5,6,7,8- tetrahydro-2-naphthoic Acid (12)

Part A - A mixture of 1-tetralon-7-carboxylic acid (7.0 g, 0.037 mol) in methanol (13.6 mL, 10.8 g, 0.30 mol) with a catalytic amount of hydrochloriic acid (0.07 mL, 0.12 g, 0.0012 mol) was stirred at reflux over 5 hours. The cooled reaction mixture was poured into ice water and extracted with ethyl acetate. The combined organic layers were backwashed with water and brine, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The resulting solid was purified by flash chromatography using hexane: ethyl acetate::75:25. The resulting solid was triturated with hexane to give 1-tetralon-7-carboxylic acid methyl ester (3.61 g, 0.018 mol, 49%) as a yellow solid, mp = 170-172°C; ¹H NMR (CDCl₃) d 8.7 (s, 1H), 8.15 (d, 1H, J=8.1 Hz), 7.35 (d, 1H,

J=8.1 Hz), 3.95 (s, 3H), 3.05 (d, 2H, J=6.1 Hz), 2.7 (t, 2H, J=6.4 Hz), 2.15 (quintet, 2H, J=6.2 Hz).

Part B - A solution of 1-tetralon-7-carboxylic acid methyl ester (3.50 g, 0.017 mol),

trimethylsilylcyanide (1.98 g, 0.02 mol) and zinc iodide (0.10 g) in benzene (20 mL) was stirred at ambient temperature over 15 hours. Then added,

sequentially and dropwise, was pyridine (20 mL) and phosphorous oxychloride (4.0 mL, 6.55 g, 0.0425 mol). The reaction mixture was stirred at reflux over 1 hour then evaporated to dryness under reduced pressure. The residue was taken up in chloroform, backwashed with water, dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure to give methyl 8-cyano-5, 6-dihydro-2-naphthoate (1.70 g, 0.008 mol, 47%) as a yellow solid, mp - 73-75°C; ¹H NMR (CDCl₃) d 8.0-7.9 (m, 1H), 7.3-7.2 (m, 1H), 6.95 (t, 1H, J=4.8 Hz), 3.95 (s, 3H), 2.9 (t, 2H, J=8.3 Hz), 2.6-2.4 (m, 3H)

Part C - A mixture of methyl 8-cyano-5,6-dihydro-2-naphthoate (0.80 g, 0.0038 mol) in methanol (25 mL) with concentrated hydrochloric acid (0.56 mL) and palladium on carbon catalyst (0.40 g, 5% Pd/C) was shaken for 20 hours at ambient temperature under an atmosphere of hydrogen (50 psi). The reaction mixture was filtered over Celite and washed with methanol. The filtrate was evaporated to dryness under reduced pressure and the residue was triturated with hexane to give the racemic mixture of methyl 8-aminomethyl¬5,6,7,8-tetrahydro-2-naphthoate (0.80 g, 0.0037 mol, 97%) as a white solid, mp = 172-179°C; ¹H NMR (DMSO) d 8.2-8.0 (m, 4H), 7.9-7.7 (m, 6H), 7.5-7.2 (m, 4H), 3.9-3.8 (m, 7H), 3.3-2.7(m, 10H), 2.0-1.6 (m, 8H).

Part D - A solution of methyl 8-aminomethyl-5,6,7,8-tetrahydro-2-naphthoate (0.78 g, 0.0036 mol) and triethylamine (0.55 mL, 0.40 g, 0.004 mol) in aqueous tetrahydrofuran (50%, 75 mL) was added, portionwise as a solid, 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile (0.99 g, 0.004 mol). All was stirred at ambient temperature over 3 hours. The solution was concentrated to half volume and extracted with diethylether. The aqueous layer was then

acidified to a pH of 1.0 using hydrochloric acid (1N) and then extraced with ethyl acetate. The combined organic layers were dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The residue was purified by flash chromatography using hexane: ethyl acetate: 8:2 to give methyl N-(BOC)-8-aminomethyl-5,6,7,8-tetrahydro-2-naphthoate (0.54 g, 0.0017 mol, 47%) as a white solid, mp = 72-80°C; ¹H NMR (DMSO) d 13.8 (s, 1H), 7.8-7.65 (m, 3H), 7.6-7.5 (m, 3H), 7.25-7.20 (m, 1H), 7.15-7.05 (m, 1H), 3.9-3.8 (m, 1H), 3.2-2.8 (m, 4H), 1.8-1.6 (m, 3H), 1.4 (s, 6H).

Part E - To a solution of methyl N-(BOC)-8-aminomethyl-5,6,7,8-tetrahydro-2-naphthoate (0.50 g, 0.0016 mol) in ethanol (12.5 mL) was added, dropwise, a solution of sodium hydroxide (0.50 g) in water (12.5 mL). The reaction was stirred at reflux for 4 hours. The reaction mixture was concentrated to half volume and then acidified to a pH equal to 1.0 using

hydrochloric acid (1N). The residue was puified by flash chromatography using a gradient of hexane:ethyl acetate: 1:1 to ethyl acetate to ethyl acetate:

methanol::9:1 to give the racemic mixture of the title compound, N-(BOC)-2-aminomethyl-5,6,7,8-tetrahydro-2-naphthoic acid (0.19 g, 0.00062 mol, 39%) as a white solid, mp = 172-176°C; ¹H NMR (DMSO) d 7.8 (s, 1H), 7.65 (d, 1H, J=8.1 Hz), 7.15 (d, 1H, J=8.1 Hz), 7.1-7.0 ·(m, 1H), 3.2-3.1 (m, 2H), 3.0-2.7 (m, 4H), 1.8-1.6 (m, 4H), 1.4 (s, 9H).

Preparation of N-(BOC)-8-aminomethyl-2-naphthoic

acid(14)

Part A - A solution of methyl 8-cyano-5,6-dihydro-2-naphthoate (1.0 g, 0.0047 mol) and 2, 3-dichloro-5,6-dicyano-1,4-benzoquinone (1.07 g, 0.0047 mol) in dioxane (50 mL) was stirred at 120°C over 16 hours. The reaction mixture was poured into ice water and extracted with ethyl acetate. The combined organic layers were dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The residue was purified by flash chromatography using ethyl acetate to give methyl 8-cyano-2-naphthoate (0.72 g, 0.0034 mol, 73%) as a tan solid, mp = 178-182°C; ¹H NMR (CDCl₃) d 8.95 (s, 1H), 8.3-8.2 (m, 1H), 8.15-8.10 (m, 1H), 8.0-7.95 (m, 2H), 7.7-7.6 (m, 1H), 4.05 (s, 1H).

Part B - A mixture of methyl 8-cyano-2-naphthoate (1.0 g, 0.0047 mol) in methanol (35 mL) with concentrated hydrochloric acid (0.69 mL) and palladium on carbon catalyst (0.20 g, 5% Pd/C) was shaken for 6 hours at ambient temperature under an atmosphere of hydrogen (50 psi). The reaction mixture was filtered over

Celite^@ and washed with methanol. The filtrate was evaporated to dryness under reduced pressure and the residue was triturated with hexane to give methyl 8-aminomethyl-2-naphthoate (0.76 g, 0.0035 mol, 75%) as an oil. ¹H NMR (DMSO) d 8.75 (s, 1H), 8.5 (bs, 2H), 8.2-8.05 (m, 3H), 7.75-7.70 (m, 2H), 4.6 (s, 2H), 3.95 (m, 3H).

Part C - To a solution of methyl 8-aminomethyl-2-naphthoate (0.75 g, 0.0035 mol) in dry tetrahydrofuran (50 mL), cooled to 0°C, was added a solution of lithium hydroxide (0.5 M, 5.83 mL). All was stirred at ambient temperature over 20 hours. Another aliquot of lithium hydroxide was added and all was stirred for an additional 20 hours. The solid was collected and the filtrate was evaporated to dryness under reduced pressure. The solids were triturated with diethyl ether to give 8-aminomethyl-2-naphthoic acid (0.67 g, 0.0033 mol, 95%) as a white solid, mp = 223-225°C; ¹H NMR (DMSO) d 8.6 (s, 1H), 8.1-7.9 (m, 1H), 7.8-7.7 (m, 4H), 7.55-7.5 (m, 1H), 7,45-7.35 (m, 2H), 4.2 (s, 2H). Part D - A solution of 8-aminomethyl-2-naphthoic acid (0.50 g, 0.00025 mol) and triethylamine (0.038 mL, 0.028 g, 0.000275 mol) in aqueous tetrahydrofuran (50%, 5 mL) was added, portionwise as a solid, 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile (0.068 g, 0.000275 mol). All was stirred at ambient temperature over 5 hours. The solution was

concentrated to half volume and extracted with

diethylether. The aqueous layer was then acidified to a pH of 1.0 using hydrochloric acid (IN) and then extraced with ethyl acetate. The combined organic layers were dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure to give the title compound, N-(BOC)-8-aminomethyl-2-naphthoic acid (0.050 g, 0.00017 mol) as a white solid, mp = 190-191°C; ¹H NMR (DMSO) d 13.1 (bs, 1H), 8.8 (s, 1H), 8.0 (q, 2H, J=7.9 Hz), 7.9 (d, 1H, J=8.1 Hz), 7.6 (t, 1H, J=7.5 Hz), 7.65-7.55 (m, 2H), 4.6 (d, 2H, J=5.5 Hz), 1.4 (s, 9H).

Example 1

Preparation of cyclic [D-2-aminobutyryl-N2-methyl-L-arginylglycyl-L-aspartyl-3-(aminomethyl)-benzoic acid]

Part A. Copper sulfate (73.8 gm, 0.462 mol) was added to a solution of L-ornithine hydrochloride (100.0 gm, 0.593 mol), sodium hydroxide (47.4 gm, 1.18 mol) in water (1000 mL), at ambient temperature. The reaction stirred for 0.5 hr and then sodium bicarbonate (59.28 gm, 0.70 mol) and carbethoxyphthalimde (148.2 gm, 0.699 mol) were added in order. The reaction mixture was stirred for 1 hr at ambient temperature giving a thick slurry. The solids were filtered off and washed with water (1000 mL), ethanol (1000 mL), chloroform (500 mL), and finally diethyl ether (500 mL). The solids were dried under vacuum to give 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-L-norvaline copper complex as a blue powder, mp >230° (225 gm, crude). 4813-97 or 170

Part B. The 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-L-norvaline copper complex was added to 6N

hydrochloric acid (1500 mL) at ambient temperature.

The reaction mixture was stirred for 1.5 hrs to give a white precipitate. The solids were filtered off and washed with 6N hydrochloric acid until the filtrate remained clear and then air dried. The product was dissolved methanol (500 mL) then ethyl acetate (1000 mL) was added to crystallize 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-L-norvaline hydrochloride as white needles mp >230° (131 gm, 0.438, 74%).¹H NMR (DMSO-d₆) δ 8.4 (bs, 3H), 7.85 (m, 4H), 3.88 (m, 1H), 3.6 (m, 2H), 1.87-1.62 (m, 4H).

4813-171-2

Part C. Sodium bicarbonate (183 gm, 2.17 mol) in water (2500 mL) was added slowly to a solution of 5- (1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-L-norvaline hydrochloride (130 gm, 0.435 mol) in 1,4-dioxane (700 mL) and water (700 mL). The reaction mixture was stirred for 0.5 hr then benzylchloroformate (81.67 gm, 0.478 mol) was added slowly and the reaction mixture stirred at ambient temperature for 2 h. The reaction mixture was extracted with ethyl acetate (2 X 500 mL). The aqueous layer was made acidic with hydrochloric acid (cone) and extracted with ethyl acetate (4 X 500 mL). The combined organic layer was washed with water, brine, dried over magnesium sulfate and concentrated in vacuo to give a colorless oil. The oil was crystallized from toluene to give 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-[(phenylmethoxy)carbonyl]-L-norvaline as a white powder, mp 127-9° (142 gm, 0.358 mol, 82%). ¹H NMR (DMSO-d₆) δ 12.6 (bs, 1H), 7.82 (m, 4H), 7.55 (d, 1H)

7.37-7.22 (m, 5H), 5.00 (s, 2H), 3.92 (m, 1H), 3.57

(m, 2H), 1.75-1.52 (m, 4H).

4813-175-2

Part D. A suspension of 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-[(phenylmethoxy)carbonyl]-L-norvaline (140 gm, 0.353 mol), p-toluenesulfonic acid (5.00 gm) and paraformaldehyde (82.8 gm, 2.76 mol) in toluene (1500 mL) in a flask fitted with a Dean Stark trap was heated to reflux for 1 hr. The reaction mixture was allowed to cool to ambient temperature, poured into a separatory funnel, washed with IH sodium hydroxide (3 X 300 mL), water, brine, dried over magnesium sulfate and concentrated to give (S)-2-[3-[5-oxo-3-[(phenylmethoxy)carbonyl]-4-oxazolidinyl]propyl]-1H-isoindole-1,3(2H)-dione as a viscous yellow oil. (150 gm), ¹H NMR (DMSO-d₆) δ 7.85 (m,

4H), 7.3 (m,6H), 5.41 (d, 1H), 5.37 (m, 1H), 5.1 (dd, 2H), 4.38 (m, 1H), 3.55 (m, 2H), 1.97-1.45 (m, 4H). 4813-180-1

Part E. The triethylsilane (123 gm, 1.05 mol) was added to a solution of crude (S)-2-[3-[5-oxo-3- [(phenylmethoxy)carbonyl]-4-oxazoli-dinyl]propyl]-1H-isoindole-1,3(2H)-dione (0.353 mol) and

trifluoroacetic acid (500 mL) in chloroform (1000 mL) at ambient temperature. The reaction mixture was stirred for 18 h and concentrated in vacuo to give a viscous oil. The oil was taken up in toluene and reconcentrated (3 X) to to give constant weight. The product was crystallized from methanol to give 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-N-[(phenylmethoxy)carbonyl]-L-norvaline as white

needles, mp 68-70° (140 gm, 0.34 mol, 96%). ¹H NMR (DMSO-d₆) δ 12.7 (bs, 1H), 7.82 (m, 4H), 7.37-7.25

(m, 5H), 5.07, 5.05 (s, 3H), 4.55 (m, 1H), 3.58 (m, 2H), 2.77, 2.75 (s, 3H), 1.91-1.47 (m, 4H).

4813-182-2 or 136-2

Part F. A solution of 5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-N-[(phenylmethoxy)carbonyl]-L-norvaline (15.0 gm, 0.0365 mol), t-butyl glycine ester hydrochloride (6.13 gm, 0.0365 mol), 1-hydroxybenzotriazole (4.94 gm, 0.0365 mol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (8.41 gm, 0.0438 mol), and 4-methylmorpholine (11.12 gm, 0.109 mol) in N,N-dimethylformamide (dried over 4A sieves) (100mL) stirred for 18 hrs at ambient

temperature. The reactiion mixture was poured into 1N hydrochloric acid (300mL) and extracted with ethyl acetate (2 X 150 mL). The combined organic layer was washed with water, brine, dried over magnesium sulfate and concentrated in vacuo to give an amber oil. The product was purified by flash chromatography on silica gel (800 mL) eluting hexane: ethyl acetate (v:v,

50:50) to give 1,1-dimethylethyl N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-N-[(phenylmethoxy)carbonyl]-L-norvalyl]glycine ester as a white foam, (16.51 gm, 0.031 mol, 86%). ¹H NMR

(DMSO-d₆) δ 8.25 (m, 1H), 7.82 (m, 4H), 7.38-7.12

(m, 5H) , 5 . 15-4 . 98 (m, 2H) , 4 . 66-4 . 52 (m, 1H) , 3 . 66 (t , 2H) , 3 . 56 (m, 2H) , 2 . 76 ( s , 3H) , 1 . 91-1 . 35 (m, 4H) , 1 . 37 ( s , 9H) .

4813-191-2 or 161-2 Part G. A solution of 1,1-dimethylethyl N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-N-[(phenylmethoxy)carbonyl]-L-norvalyl]glycine ester (16.2 gm, 0.031 mol) in methanol (100 mL) was degassed with nitrogen, then 10% palladium on charcoal (1.0 gm) and ammonium formate (10.5 gm, 0.166 mol) were added and the reaction stirred overnight at ambient

temperature. The reaction was filtered through celite and the filtrate was concentrated to give a foam. The crude product was taken up in ethyl acetate (300 mL), washed with water (100 mL), brine, dried over

magnesium sulfate and concentrated to give 1,1-dimethylethyl N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-1-norvalyl]glycine ester as a white foam (12.0 gm, 0.031 mol, 100%). ¹H NMR (DMSO-d₆) δ

8.55 (t, 1H), 7.85 (m, 4H), 3.82-3.66 (m, 2H), 3.57 (m, 2H), 2.28 (s,3H), 1.73-1.55 (m, 4H), 1.35 (s, 9H).

1029-2-1

Part H. A solution of 1,1-dimethylethyl N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-1-norvalyl]glycine ester (10.5 gm, 0.027 mol), N-[(phenylmethoxy)carbonyl]-D-2-aminobutanoic acid (6.39 gm, 0.027 mol), O-benzotriazol-1-yl-N,N,N',N',-tetramethyluroniumhexafluorophosphate (12.27 gm,

0.0324 mol), and 4-methyl morpholine (6.57 gm, 0.0647 mol), in methylene chloride (300 mL) was stirred for 18 hrs at ambient temperature. The reaction was diluted with additional methylene chloride (200 mL), washed with 1N hydrochloric acid, water, brine, dried over magnesium sulfate and concentrated to give a amber oil. The product was purified by flash

chromatography on silica gel (500mL), eluting toluene: ethyl acetate (v:v, 60:40) to give 1,1-dimethylethyl (N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-N-[N-[(phenylmethoxy)carbonyl]-D-2-aminobutyryl]-L-norvalyl]-glycine) ester as a glass, (13.4 gm, 0.022 mol, 83%). ¹H NMR (DMSO-d₆) δ 7.92-7.77 (m, 5H), 7.46-7.1 (m, 6H), 5.05-4.95 (m, 3H),

4.41 (m, 1H), 3.72-3.55 (m, 4H), 2.92, 2.72 (s, 3H),

1.95-1.38 (m, 6H), 1.35 (s, 9H), 0.86 (t, 3H).

1029-9-3 Part I. 10% palladium on charcoal (3.0 gm) and ammonium formate (13.0 gm, 0.21 mol) were added to a solution of 1, 1-dimethylethyl (N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-N-[N-[(phenylmethoxy)carbonyl]-D-2-aminobutyryl]-L-norvalyl]-glycine) ester (13.0 gm, 0.021 mol) in methanol (300 mL), at ambient temperature. The reaction mixture was stirred for 48 hrs, filtered through celite and was concentrated to give a solid. The product was partitioned between water and ethyl acetate. The organic layer was washed with brine, dried over magnesium sulfate and concentrated to give 1,1-dimethylethyl N-[N-(D-2-aminobutyryl)-5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-L-norvalyl]glycine ester as a foam (7.3 gm, 0.0154 mol, 73%). ¹H NMR (DMSO-d₆) δ 8.02 (t, 1H), 7.82 (m,

4H), 5.05 (m, 1H), 3.75-3.5 (m, 6H), 2.85, 2.75 (s, 3H), 1.93-1.22 (m, 6H), 1.35 (s, 9H), 0.85 (t, 3H). 1029-14-1 Part J. To a solution of 4-methyl morpholine (45.68 gm, 0.45 mol) and 4-phenylmethoxy-2-[[(1,1-dimethylethoxy)carbonyl]amino-4-oxobutanoic acid (S) (46.53 gm, 0.144 mol) in N,N-dimethylformamide (dried over 4A sieves) (400 mL), 1-1'-carbonyldiimidazole (24.32 gm, 0.15 mol) was added. The reaction mixture was strirred for 0.75 hr at ambient temperature and 3-(aminomethyl)benzoic acid hydrochloride (27.0 gm, 0.144 mol) was added. The reaction mixture was stirred for 18 hrs at ambient temperature, poured into IN hydrochloric acid (600 mL) and was extracted with ethyl acetate (2 X 800 mL). The combined organic layer was washed with IH hydrochloric acid, water, brine, dried over magnesium sulfate and concentrated in vacuo to give a viscous oil. The product was crystallized from diethyl ether to give (phenylmethyl-4-[[(3-carboxyphenyl)methyl]amino]-3-[[(1,1-dimethylethoxy)carbonyl]amino-4-oxobutanoate (S) as a white crystalline powder, mp 154-7° (52.1 gm, 0.114 mol, 80%) ¹H NMR (DMSO-d₆) δ 12.9 (bs, 1H), 8.42 (t, 1H), 7.82 (S,1H), 7.77 (d, 1H), 7.5-7.27 (m, 7H), 7.15 (d, 1H), 5.06 (s, 2H), 4.42-4.25 (m, 3H), 2.87-2.58 (m,2H), 1.35 (s, 9H).

55-142-2 Part K. A solution of 1,1-dimethylethyl N-[N-(D-2-aminobutyryl)-5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-L-norvalyl]glycine ester (7.0 gm, 0.0148 mol), (phenylmethyl-4-[[(3-carboxyphenyl)methyl]amino]-3-[[(1,1-dimethylethoxy)carbonyl]amino-4-oxobutanoate (S) (6.74 gm, 0.0148 mol), O-benzotriazol-1-yl-N, N,N ' , N ' , -tetramethyluroniumhexafluorophosphate (6.72 gm,

0.01770 mol) and 4-methyl morpholine (4.48 gm, 0.044 mol) in N,N-dimethylformamide (dried over 4A sieves) (200 mL) stirred at ambient temperature for lδhrs.

The reaction mixture was poured into 1N hydrochloric acid (200 mL) and was extracted with ethyl acetate (2 X 300 mL). The combined organic layer was washed with water, brine, dried over magnesium sulfate and

concentrated in vacuo to give a viscous oil. The product was purified by flash chromatography on silica gel (500 mL) eluting hexane: ethyl acetate, (v:v, 30:70) to give 1,1-dimethylethyl N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-[N-[3-[[[2-[[(1,1-dimethylethoxy)carbonyl]amino]-1,4-dioxo-4-(phenylmethoxy)butyl]amino]methyl]benzoyl]-D-2-aminobutyryl]-N-methyl-L-norvalyl]glycine ester as a white foam, mp 76-80° (10.8 gm, 0.0118 mol, 80%). ¹H NMR (DMSO-d₆) δ

8.5-8.30 (m, 2H), 8.05-7.56 (m, 7H), 7.4-7.07 (m, 8H), 5.1-5.0 (m, 3H), 4.85-4.62 (m, 1H), 4.45-4.22 (m, 3H), 3.77-3.47 (m, 4H), 2.95, 2.75 (s, 3H), 2.85-2.56 (m, 2H), 2.0-1.22 (m, 24H), 0.88 (m, 3H).

1029-16-2 or 4813-187-2 Part L. A solution of 1,1-dimethylethyl N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-[N-[3-[[[2-[[(1,1-dimethylethoxy)carbonyl]amino]-1,4-dioxo-4- (phenyl-methoxy)butyl]amino]methyl]benzoyl]-D-2-aminobutyryl]-N-methyl-L-norvalyl]glycine ester (26.7 gm, 0.0292 mol), methylene chloride (150 mL) and trifluoroacetic acid (100 mL) was stirred at ambient temperature for 2.5 h. The reaction mixture was concentrated in vacuo to give a viscous oil. The oil was taken up in acetonitrile and reconcentrated. This was repeated until a constant weight was obtained. The product was isolated to give N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-[N-[3-[[[2-[amino]-1,4-dioxo-4-(phenyl-methoxy)butyl]amino]methyl]benzoyl]-D-2-aminobutyryl]-N-methyl-L-norvalyl]glycine acid as a white foam (29.0 gm crude). ¹H NMR (DMSO-d₆) δ 9.0

(m, 1H), 8.52 (m, 1H), 8.30 (bs, 3H), 8.02 (t, 1H), 7.9-7.65 (m, 6H), 7.43-7.25 (m, 7H), 5.17-5.02 (m, 3H), 4.8 (m, 1H), 4.35 (m, 2H), 4.18 (m, 1H), 3.84-3.5 (m, 4H), 3.07-2.86 (m, 2H), 2.97, 2.75 (s, 3H), 1.95-1.45 (m, 6H), 0.91 (t, 3H). 1029-45-1 or 7-1

Part M. A solution of N-[5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-[N-[3-[[[2-[amino]-1,4-dioxo-4-(phenyl-methoxy)butyl]amino]methyl]benzoyl]-D-2-aminobutyryl]-N-methyl-L-norvalyl]glycine acid (21.5 gm, 0.0247 mol) in acetonitrile (150 mL) was added slowly, over 3.5 hr, to a solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (8.37 gm, 0.0437 mol), and 4-methyl morpholine (11.8 gm, 0.117) in acetonitrile (350 mL) at ambient

temperature. The reaction stirred an additional 2 hrs and was diluted with ethyl acetate (800mL), washed with 1N hydrochloric acid (3 X 75 mL), water, brine, dried over magnesium sulfate and concentrated in vacuo to give a foam. The product was purified by filtering through a plug of silica gel eluting with

acetonitrile, concentrating in vacuo to a gum and triturating with diethyl ether to give cyclic[4-oxo-4-(phenylmethoxy)-L-2-aminobutyryl-3- (aminomethyl)benzoyl-D-2-aminobutyryl-5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-L-norvalylglycine]

as a white powder, mp 95-100° (15.5 gm, 0.021, 85%). ¹H NMR (DMSO-d₆) δ 8.85 (d, 1H), 8.60 (d, 1H), 8.52

(t, 1H), 7.82 (m, 4H), 7.67 (m, 1H), 7.57 (d, 1H), 7.46 (s, 1H), 7.42-7.25 (m, 7H), 5.28 (dd, 1H), 5.08 (s, 2H), 4.67-4.5 (m, 3H), 4.17 (dd, 1H), 4.0 (dd, 1H), 3.60 (t, 2H), 2.9 (s, 3H), 2.87 (dd, 1H), 2.65 (dd, 1H), 2.05-1.42 (m, 6H), 0.95 (t, 3H).

1029-49-2

Part N. A degassed solution of cyclic[4-oxo-4- (phenylmethoxy)-L-2-aminobutyryl-3- (aminomethyl)benzoyl-D-2-aminobutyryl-5-(1,3-dihydro- 1,3-dioxo-2H-isoindol-2-yl)-N-methyl-L-norvalylglycine] (15.77 gm, 0.0213 mol), cyclohexene (75 mL), palladium hydroxide on charcoal (3.0 gm) in ethanol (200 mL) was heated to reflux for 8 hrs. The reaction was allowed to cool to ambient temperature, was filtered through celite and concentrated in vacuo to give cyclic[L-aspartyl-3-(aminomethyl)benzoyl-D-2-aminobutyryl-5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-L-norvalylglycine] as an off white foam,mp 105-10° (13.2 gm, 0.020 mol, 95%) ¹H NMR (DMSO-d₆) δ 8.65 (d, 1H), 8.52 (d, 1H), 8.45 (m, 1H), 7.95 (m, 5H), 7.70 (m, 1H), 7.62 (m, 1H), 7.47 (s, 1H), 7.4-7.27 (m, 3H), 5.17 (m, 1H), 4.67-4.50 (m, 3H) , 4.18 (dd, 1H), 4.05 (dd, 1H), 3.6 (m, 2H), 2.91 (s, 3H), 2.7 (dd, 1H), 2.5 (dd, 1H), 2.02-1.45 (m, 6H), 0.95 (t, 3H).

1029-52-2 or 50-1

Part O. A solution of cyclic[L-aspartyl-3- (aminomethyl)benzoyl-D-2-aminobutyryl-5-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-N-methyl-L-norvalylglycine] in methanol (50 mL) and 40%

methylamine in water (25 mL) was stirred at ambient temperature for 3 hrs and was concentrated in vacuo to remove the methanol. The aqueous layer was diluted with ethanol and was concentrated in vacuo to give a precipitate. The semisolid was triturated with ethanol and diethyl ether sequencially to give the cyclic[L-aspartyl-3-(aminomethyl)benzoyl-D-2-aminobutyryl-N-methyl-L-ornithylglycine] as a white powder, mp 198-200° (5.6 gm, 0.11 mol, 51%) ¹H NMR (DMSO-d₆) δ 8.87 (m, 1H), 8.52 (m, 1H), 8.42 (m, 1H), 7.7-7.6 (m, 2H), 7.57 (s, 1H), 7.3 (m, 3H), 5.11 (m, 1H), 4.6 (m, 1H), 4.5-4.32 (m, 2H), 4.17-3.95 (m. 2H), 3.77 (m, 1H), 2.92 (s, 3H), 2.67 (m, 2H), 2.3 (m,

2H), 2.07-1.32 (m, 6H), 0.95 (t, 3H) .

1029-53-2 Part P. To a solution of cyclic[L-aspartyl-3- (aminomethyl)benzoyl-D-2-aminobutyryl-N-methyl-L-ornithylglycine] (5.25 gm, 0.0101 mol) and N,N-dimethylaminopyridine (2.47 gm, 0.0202 mol), in ethanol (50 mL) and water (15 mL) at ambient

temperature, formamidine sulfonic acid (1.25 gm,

0.0101 mol) was added portionwise. The reaction stirred for 0.5 hrs and was concentrated in vacuo. The product was triturated with ethanol (3 X 200 mL) to give cyclic[D-2-aminobutyryl-N2-methyl-L-arginylglycyl-L-aspartyl-3- (aminomethyl)-benzoic acid] as a white powder, mp 238-40° (5.1 gm, 0.0091 mol,90%). ¹H NMR (D₂O/DCl) δ

7.42 (d, 1H), 7.22 (m, 2H), 7.12 (s, 1H), 5.12 (dd, 1H), 4.57-4.42 (m, 3H), 4.35 (d, 1H), 4.1 (d, 1H), 3.62 (d, 1H), 3.0 (m, 2H), 2.92 (s, 3H), 2.75 (dd, 1H), 2.62 (dd, 1H), 1.95 (m, 1H), 1.77-1.55 (m, 3H), 1.4-1.25 (m, 2H), 0.80 (t, 3H).

Claims (12)

WHAT IS CLAIMED IS :

1. A process for the preparation of a compound of formula:

comprising the steps of:

(a) coupling an amino tripeptide of formula:

, wherein Z is a suitable carboxylic acid protecting group and Y is a suitable amine protecting group, with a carboxylic acid

derivitive of formula:

, wherein G is a suitable amine protecting group, to produce a protected linear peptide of

formula:

,

(b) removing the Z and G protecting groups of the product of Step (a) to produce a deprotected linear peptide of formula:

;

(c) cyclizing the deprotected linear peptide of Step (b) to produce a cyclic peptide of formula:

;

(d) converting the benzyl ester group of the product of Step (c) to an acid of formula:

; (e) deprotecting the amine group of the product of Step (d) to produce an amine of formula:

; and

(f) reacting the product of Step (e) with a reagent capable of converting an amine to guanidine to produce a compound of formula (I), wherein :

w is 0 or 1 ;

R¹ is

, wherein :

p and p ' are 0 or 1 ;

R¹⁹ is a C₆-C₁₄ saturated, partially

saturated, or aromatic carbocyclic ring system or heterocyclic ring system composed of at least 1-3 heteroatoms selected from N, O, S; all these ring systems may be optionally substituted with 0-2 R⁷; R¹⁷ and R¹⁶ are independently selected from the group: hydrogen;

C₁-C₄ alkyl, optionally substituted with halogen;

C₁-C₂ alkoxy;

benzyl;

R¹⁵ and R¹⁸ are independently selected from the group: hydrogen,

C₁-C₈ alkyl substituted with 0-2 R⁸, C₂-C₈ alkenyl substituted with 0-2 R⁸, C₂-C₈ alkynyl substituted with 0-2 R⁸, C3-C8 cycloalkyl substituted with 0-2

R⁸,

C₆-C₁₀ bicycloalkyl substituted with 0-2 R⁸, aryl substituted with 0-2 R¹³, a heterocylic ring system composed of 5-10 atoms including 1-3 nitrogen, oxygen, or sulfur heteroatoms,

optionally substituted with 0-2 R¹³; R¹⁵ and R¹⁷ can alternatively join to form a

5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁸ and R¹⁶ can alternatively join to form a

5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁵ and R¹⁴ can alternatively join to form a 5-8 membered carbocyclic ring

substituted with 0-2 R¹³, when R¹⁷ is H;

R⁷ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀

arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R²⁰, -C(=O)R²⁰,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl optionally substituted with

-NR²⁰R²¹;

R⁸ is independently selected at each

occurrence from the group:

=O, F, Cl, Br, I , -CF₃, -CN, -CO₂R²⁰, -C (=O) NR²⁰R²¹ , -CH₂OR²⁰, -OC (=O) R20 , -CH₂NR²⁰R²¹ , -NR²⁰R²¹ ; R¹³ is independently selected at each occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀ arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆ cycloalkoxy, -OC(=O)R20, -C(=O)R20,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl (substituted with -NR²⁰R²¹); R²⁰ is independently selected at each

occurrence from the group:

H, C₁-C₇ alkyl, aryl, -(C₁-C₆

alkyl) aryl, or C₃-C₆ alkoxyalkyl;

R²¹ is independently selected at each

occurrence from the group:

H, C₁-C₄ alkyl, or benzyl;

R¹¹ is H or C₁-C₈ alkyl ;

R¹² is H or C₁-C₈ alkyl ; R¹⁴ is H or C₁-C₈ alkyl ;

R² is H, C₁-C₈ alkyl , C₃-C₆ cycloalkyl , C₃-C₆ cycloalkylmethyl , C₁-C₆ cycloalkylethyl, phenyl , phenylmethyl , CH₂OH, CH₂SH,

CH₂OCH₃, CH₂SCH₃ , CH₂CH₂SCH₃, (CH₂ ) _sNH₂ , (CH₂)_sNHC (=NH) (NH₂), (CH₂)_sNHR²¹, wherein s = 3-5;

R¹² and R² can be taken together to form-(CH₂)_t- , wherein t = 2-4, or -CH₂SC(CH₃)₂-;

R³ is H or C₁-C₈ alkyl;

A is selected from the group:

-(C₁-C₇ alkyl)-, , wherein q is 0,1,

, wherein q is

0,1,

, wherein v is 0-3 and provided that w is 0,

-(CH₂)_mO-(C₁-C₄ alkyl)-, wherein m = 1,2, -(CH₂)_mS-(C₁-C₄ alkyl)-, wherein m = 1,2; R³ and A may also be taken together to form ,

wherein n = 0-1 and provided that w = 0;

R⁹ is H, C₁-C₈ alkyl; and

R⁵ is H, C₁-C₈ alkyl. 2. The process of Claims 1 wherein:

R¹⁹ is selected from:

, ,

,

or

;

R¹⁵ and R¹⁸ are independently selected from

H, C₁-C₄ alkyl, phenyl, benzyl,

phenyl-(C₂-C₄)alkyl, C₁-C₄ alkoxy;

R¹⁷ and R¹⁶ are independently H or C₁-C₄

alkyl; R⁷ is H, C₁-C₈ alkyl, phenyl, halogen, or C₁-C₄

alkoxy;

R¹¹ is H or C₁-C₃ alkyl; R¹² is H or CH₃;

A is -(C₁-C₇, alkyl), , wherein q is 0,1 ,

-(CH₂)_mS(CH₂)₂-, Wherein m = 1,

2

Wherein v is 0-3 and provided that w = 0

R³ and A may be taken together to form , wherein, n = 0- 1 and provided that w = 0; R⁹ is H, C₁-C₃ alkyl; R⁵ is H, C₁-C₃ alkyl.

3. The process of Claim 2 wherein:

R⁵, R⁹, R¹⁶, R¹⁷ and R¹⁸ are H;

R¹¹, R¹², and R¹⁴ are H or CH₃;

R¹⁵ is H, C₁-C₄ alkyl, phenyl, benzyl, or

phenyl- (C₂-C₄) alkyl; and

R³ is H or C₁-C₃ alkyl.

4. The process of Claim 1 wherein: w is 1;

p is 0;

_R19 is ;

R⁵, R⁹, R¹⁷, R¹⁵,R¹¹, R¹², R¹⁴ are H;

R² is C₂H₅;

R³ is CH₃; and

A is -(CH₂)₃-.

5. A process for the preparation of a compound of formula:

comprising cyclizing a compound of formula:

wherein:

Y is pthalyl, t-BOC, CBZ, CBZNH-C (=N-CBZ) -, t-BOCNH-C(=Nt-BOC)-, Tos-NH-C(=NH)-, CF₃C(=O)-;

R¹ is , wherein; p and p ' are 0 or 1 ;

R¹⁹ is a C₆-C₁₄ saturated, partially

saturated, or aromatic carbocyclic ring system or heterocyclic ring system composed of at least 1-3 heteroatoms selected from N, O, S; all these ring systems may be optionally substituted with 0-2 R⁷;

R¹⁷ and R¹⁶ are independently selected from the group: hydrogen;

C₁-C₄ alkyl, optionally substituted with halogen;

C₁-C₂ alkoxy;

benzyl;

R¹⁵ and R¹⁸ are independently selected from the group: hydrogen,

C₁-C₈ alkyl substituted with 0-2 R⁸, C₂-C₈ alkenyl substituted with 0-2 R⁸, C₂-C₈ alkynyl substituted with 0-2 R⁸, C₃-C₈ cycloalkyl substituted with 0-2 R⁸,

C₆-C₁₀ bicycloalkyl substituted with 0-2 R⁸, aryl substituted with 0-2 R¹³ , a heterocylic ring system composed of 5-10 atoms including 1-3 nitrogen, oxygen, or sulfur heteroatoms,

optionally substituted with 0-2 R¹³;

R¹⁵ and R¹⁷ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³; R¹⁸ and R¹⁶ can alternatively join to form a

5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁵ and R¹⁴ can alternatively join to form a 5-8 membered carbocyclic ring

substituted with 0-2 R¹³, when R¹⁷ is H;

R⁷ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀

arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R²⁰, -C(=O)R²⁰,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl optionally substituted with

-NR²⁰R²¹;

R⁸ is independently selected at each

occurrence from the group: =O, F, Cl, Br, I, -CF₃, -CN, -CO₂R²⁰, -C(=O)NR²⁰R²¹, -CH₂OR²⁰, -OC(=O)R20, -CH₂NR²⁰R²¹, -NR²⁰R²¹; R¹³ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀ arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆ cycloalkoxy, -OC(=O)R20, -C(=O)R20,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl (substituted with -NR²⁰R²¹);

R²⁰ is independently selected at each

occurrence from the group:

H, C₁-C₇ alkyl, aryl, -(C₁-C₆

alkyl) aryl, or C₃-C₆ alkoxyalkyl;

R²¹ is independently selected at each

occurrence from the group:

H, C₁-C₄ alkyl, or benzyl; R¹¹ is H or C₁-C₈ alkyl; R¹² is H or C₁-C₈ alkyl; R¹⁴ is H or C₁-C₈ alkyl; R² is H, C₁-C₈ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₁-C₆ cycloalkylethyl, phenyl, phenylmethyl, CH₂OH, CH₂SH,

CH₂OCH₃, CH₂SCH₃, CH₂CH₂SCH₃, (CH₂)_sNH₂, (CH₂)_sNHC(=NH) (NH₂), (CH₂)_sNHR²¹, wherein s = 3-5;

R¹² and R² can be taken together to form- (CH₂)_t- , wherein t = 2-4, or -CH₂SC(CH₃)₂-;

R¹⁴ and R² can be taken together to form -(CH₂)_u- , wherein u = 2-5;

R³ is H or C₁-C₈ alkyl;

A is selected from the group:

-(C₁-C₇ alkyl)-,

, wherein q is 0,1;

,

, wherein v is 0-3,

- (CH₂)_mO- (C₁-C₄ alkyl)-, wherein m = 1,2,

- (CH₂)_mS-(C₁-C₄ alkyl)-, wherein m = 1,2;

R³ and A may also be taken together to form

, wherein n = 0-1;

R⁹ is H, C₁-C₈ alkyl; and

R⁵ is H, C₁-C₈ alkyl.

6. The process of Claim 5 wherein:

Y is phthalyl, CBZ, CBZNH-C(=NCBZ)-,

Tos-NH-C(=NH)-;

R¹⁹ is selected from: , ,

,

or

;

R¹⁵ and R¹⁸ are independently selected from

H, C₁-C₄ alkyl, phenyl, benzyl, phenyl-(C₂-C₄)alkyl, C₁-C₄ alkoxy;

R¹⁷ and R¹⁶ are independently H or C₁-C₄

alkyl;

R⁷ is H, C₁-C₈ alkyl, phenyl, halogen, or

C₁-C₄

alkoxy;

R¹¹ is H or C₁-C₃ alkyl;

R¹² is H or CH₃; A is selected from the group:

- (C₁-C₇ alkyl ) -, , wherein q is 0,1; ,

, wherein v is 0-3,

- (CH₂)_mO-(C₁-C₄ alkyl)-, wherein m = 1,2,

- (CH₂)_mS-(C₁-C₄ alkyl)-, wherein m = 1,2;

R³ and A may also be taken together to form , wherein n = 0-1;

R⁹ is H, C₁-C₈ alkyl; and

R⁵ is H, C₁-C₈ alkyl

7. The process of Claim 6 wherein: R⁵, R⁹, R¹⁶, R¹⁷ and R¹⁸ are H;

R¹¹, R¹², and R¹⁴ are H or CH₃;

R¹⁵ is H, C₁-C₄ alkyl, phenyl, benzyl, or phenyl-(C₂-C₄)alkyl; and

R³ is H or C₁-C₃ alkyl.

8. The process of Claim 7 wherein:

Y is phthalyl;

p is 0;

_R19 is ;

R⁵, R⁹, R¹⁷, R¹⁵,R¹¹, R¹², R¹⁴ are H; R² is C₂H₅;

R³ is CH₃; and

A is -(CH₂)₃-.

9. The compounds of formulae:

Formula III Formula IV wherein:

wherein:

Y is H, phthalyl, t-BOC, CBZ, t-BOCNH-C(=Nt-BOC)-, CBZ-NH-C(=NCBZ)-, Tos-NH-C(=NH)-,

CF₃C(=O)-; Z is H, t-butyl, benzyl, alkyl, t-BOC;

G is H, t-BOC, CBZ;

R¹ is , wherein: p and p' are 0 or 1; R¹⁹ is a C₆-C₁₄ saturated, partially saturated, or aromatic carbocyclic ring system or heterocyclic ring system composed of at least 1-3 heteroatoms selected from N, O, S; all these ring systems may be optionally substituted with 0-2 R⁷;

R¹⁷ and R¹⁶ are independently selected from the group: hydrogen;

C₁-C₄ alkyl, optionally substituted with halogen;

C₁-C₂ alkoxy;

benzyl;

R¹⁵ and R¹⁸ are independently selected from the group: hydrogen,

C₁-C₈ alkyl substituted with 0-2 R⁸, C₂-C₈ alkenyl substituted with 0-2 R⁸, C₂-C₈ alkynyl substituted with 0-2 R⁸,

C₃-C₈ cycloalkyl substituted with 0-2

R⁸,

C₆-C₁₀ bicycloalkyl substituted with

0-2 R⁸, aryl substituted with 0-2 R¹³, a heterocylic ring system composed of 5-10 atoms including 1-3 nitrogen. oxygen, or sulfur heteroatoms,

optionally substituted with 0-2 R¹³;

R¹⁵ and R¹⁷ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁸ and R¹⁶ can alternatively join to form a 5-7 membered carbocyclic ring

substituted with 0-2 R¹³;

R¹⁵ and R¹⁴ can alternatively join to form a 5-8 membered carbocyclic ring

substituted with 0-2 R¹³, when R¹⁷ is H;

R⁷ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀

arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆

cycloalkoxy, -OC(=O)R²⁰, -C(=O)R²⁰,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl optionally substituted with -NR²⁰R²¹;

R⁸ is independently selected at each

occurrence from the group: =O, F, Cl, Br, I, -CF₃, -CN, -CO₂R²⁰,

-C(=O)NR²⁰R²¹, -CH₂OR²⁰, -OC(=O)R20, -CH₂NR²⁰R²¹, -NR²⁰R²¹;

R¹³ is independently selected at each

occurrence from the group: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C₁-C₅ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₇-C₁₀ arylalkyl, C₁-C₄ alkoxy, -CO₂R²⁰, sulfonamide, formyl, C₃-C₆ cycloalkoxy, -OC(=O)R20, -C(=O)R20,- OC(=O)OR²⁰, -OR²⁰, -CH₂OR²⁰, C₁-C₄ alkyl (substituted with -NR²⁰R²¹);

R²⁰ is independently selected at each

occurrence from the group:

H, C₁-C₇ alkyl, aryl, -(C₁-C₆

alkyl) aryl, or C₃-C₆ alkoxyalkyl; R²¹ is independently selected at each

occurrence from the group:

H, C₁-C₄ alkyl, or benzyl; R¹¹ is H or C₁-C₈ alkyl;

R¹² is H or C₁-C₈ alkyl;

R¹⁴ is H or C₁-C₈ alkyl; R² is H, C₁-C₈ alkyl, C₃-C₆ cycloalkyl, C₃-C₆ cycloalkylmethyl, C₁-C₆ cycloalkylethyl, phenyl, phenylmethyl, CH₂OH, CH₂SH,

CH₂OCH₃, CH₂SCH₃, CH₂CH₂SCH₃, (CH₂)_sNH₂, (CH₂)_sNHC(=NH) (NH₂), (CH₂)_sNHR²¹, wherein s = 3-5;

R¹² and R² can be taken together to form- (CH₂)_t- , wherein t = 2-4, or -CH₂SC(CH₃)₂-;

R³ is H or C₁-C₈ alkyl;

A is selected from the group: - (C₁-C₇ alkyl)-,

, wherein q is

0,1;

, , wherein v is 0-3,

-(C(₂)_mO-(C₁-C₄ alkyl)-, wherein m = 1,2, -(CH₂)_mS-(C₁-C₄ alkyl)-, wherein m = 1,2;

R³ and A may also be taken together to form

, wherein n = 0-1; atoms; R⁹ is H, C₁-C₈ alkyl;

R⁵ is H, C₁-C₈ alkyl; and

R²⁵ is H or benzyl.

10. The compounds of Claim 9, wherein:

Y is H, phthalyl, CBZ, CBZ-NH-C(=NCBZ)-,

Tos-NH-C(=NH)-, CF₃C(=O)-;

Z is H, t-butyl;

G is H, t-BOC; R¹⁹ is selected from:

, ,

,

or

;

R¹⁵ and R¹⁸ are independently selected from

H, C₁-C₄ alkyl, phenyl, benzyl, phenyl- (C₂-C₄) alkyl, C₁-C₄ alkoxy;

R¹⁷ and R¹⁶ are independently H or C₁-C₄

alkyl;

R⁷ is H, C₁-C₈ alkyl, phenyl, halogen, or

C₁-C₄

alkoxy;

R¹¹ is H or C₁-C₃ alkyl;

R¹² is H or CH₃;

A is C₁-C₇ alkyl.

, wherein q is 0, 1, , wherein q is

0,1,

-(CH₂)_mS(CH₂)₂-, wherein m = 1,2,

, wherein v is 0-3; and

R³ and A may be taken together to form , wherein n = 0-1 atoms;

R⁹ is H, _C1-C₃ alkyl;

R⁵ is H, C₁-C₃ alkyl,

11. The compounds of Claim 10, wherein:

R⁵, R⁹, R^lβ, R¹⁷ and R¹⁸ are H;

R¹¹, R¹², and R¹⁴ are H or CH₃; R¹⁵ is H, C₁-C₄ alkyl, phenyl, benzyl, or phenyl-(C₂-C₄)alkyl; and

R³ is H or C₁-C₃ alkyl.

12. The compounds of Claim 11, wherein:

Y is phthalyl;

p is 0;

_R19 is ;

R⁵, R⁹, R¹⁷, R¹⁵,R¹¹, R¹², R¹⁴ are H; R² is C₂H₅;

R³ is CH₃; and

A is -(CH₂)₃-.