Patent ID: 8148362

Claim:
A compound of the formula: or a pharmaceutically acceptable salt thereof wherein Y 1 is NP 2 or O; P 1 and P 2 are independently hydrogen, a substituent selected from Substituent Group S1 or an amino protecting group, or P 1 and P 2 may be taken together with N atom to which they are attached to form optionally substituted heterocycle; Substituent Group S1 consists of optionally substituted lower alkyl, optionally substituted cycloalkyl, optionally substituted formyl, optionally substituted lower alkylcarbonyl, optionally substituted cycloalkylcarbonyl, optionally substituted lower alkyloxycarbonyl, optionally substituted arylcarbonyl, optionally substituted heterocyclecarbonyl, optionally substituted carbamoyl, lower alkylthio, cycloalkylthio, arylthio, optionally substituted lower alkylsulfonyl, optionally substituted phenylsulfonyl, optionally substituted aromatic heterocycle(lower)alkyl, optionally substituted aryl, and optionally substituted heterocyclic group; Ring B is optionally substituted and optionally condensed benzene ring or optionally substituted heterocycle; with the proviso that the compound is not the following compounds: wherein Ph is phenyl.