Diaminopropionic acid derivatives

A compound of formula

• wherein U is chlorine, bromine, fluorine, or methyl;
• R3 is hydrogen, carboxy, or lower alkyl;
• X is carbonyl, phenyl-substituted loweralkylene, or sulfonyl;
• Y is lower alkylene which may be substituted by one or more of amino, substituted amino, loweralkyl, or cyclo lower alkyl, or Y is lower alkenylene or lower alkylenethio, k is 0 or 1;
• when k is 1, Z is hydrogen, lower alkylthio, —COOH, —CONH2, or amino, or when k is 0 or 1, Z is:
• 1-adamantyl, diphenylmethyl,3-[[(5-chloropyridin-2-yl)amino]carbonyl]pyrazin-2-yl, hydroxy, phenylmethoxy, 2-chloro-4-[[[(3-hydroxyphenyl)methyl]amino]carbonyl]phenyl, [(2,6-dichlorophenyl)methoxy]phenyl or Z is one of the following:
• cycloalkyl or aryl containing 0 to 3 heteroatoms which may be the same or different, or a fused ring system containing two or three rings which rings are independently cycloalkyl or aryl containing 0 to 3 heteroatoms which may be the same or different, any of which rings may be unsubstituted, or substituted with at least one of:
• halogen, cyano, amino, substituted amino, aminosulfonyl, nitro, oxo, hydroxy, aryl, aryloxy, unsubstituted lower alkyl, halogen-substituted lower alkyl, lower alkoxy-substituted lower alkyl, lower alkoxy, lower alklanesulfonyl, lower alkylthio, acetyl, aminocarbonyl, hydrazino, carboxy, lower alkoxycarbonyl, acetoxy, or amino loweralkyl;
• or a pharmaceutically acceptable salt or ester thereof.