A compound of the formula: wherein R3represent a C1-8alkyl which is unbranched or branched and unsubstituted or substituted with OH, alkoxy, CO2H, ═NOH, ═NOCONH2, or ═O; C3-8cycloalkyl which is unsubstituted or substituted with OH, alkoxy, CO2H, ═NOH, ═NOCONH2, or ═O; C4-8cycloalkylalkyl wherein the cycloalkyl portion is unsubstituted or substituted with OH, alkoxy, CO2H, ═NOH, ═NOCONH2, or ═O; aryl which is unsubstituted or substituted with Cl, NH2, alkylamino, dialkylamino, amido, C1-C8alkylamido, C1-C3dialkylamido, OH, alkoxy, HC═NOH, HC═NOCONH2, C1-C3alkyl, phenyl or benzyl; aralkyl (C1-4); heterocyclyl; heterocyclylalkyl (C1-C4); and heteroaryl; R8represents H or a C1-8alkyl which is unbranched or branched and unsubstituted or substituted with OH, alkoxy, CO2H, ═NOH, ═NOCONH2, or ═O; C3-8cycloalkyl which is unsubstituted or substituted with OH, alkoxy, CO2H, ═NOH, ═NOCONH2, or ═O; C4-8cycloalkylalkyl wherein the cycloalkyl portion is unsubstituted or substituted with OH, alkoxy, CO2H, ═NOH, ═NOCONH2, or ═O; aryl which is unsubstituted or substituted with Cl, NH2, alkylamino, dialkylamino, amido, C1-C8alkylamido, C1-C3dialkylamido, OH, alkoxy, HC═NOH, HC═NOCONH2, C1-C3alkyl, phenyl or benzyl; aralkyl (C1-4); heterocyclyl; heterocyclylalkyl (C1-C4); and heteroaryl.