| 摘要 |
<p>A compound of the formula : <CHEM> wherein R<1> is lower alkyl, halo(lower)alkyl, cyclo(lower)alkyl or lower alkylthio, R<2> is hydrogen or imino-protective group, R<3> is hydrogen or halogen, A is lower alkylene, and <CHEM> is a group of the formula : <CHEM> in which X<1>, X<2>, X<3> and X<4> are each N or CR<4>, in which R<4> is hydrogen, lower alkyl, lower alkoxy, halogen, halo(lower)alkyl, esterified carboxy, halo(lower)alkoxy or hydroxy, provided that at least one of X<1>, X<2>, X<3> and X<4> is N, and pharmaceutically acceptable salts thereof, processes for their preparation and pharmaceutical compositions comprising them as an active ingredient in admixture with a pharmaceutically acceptable carrier or excipient.</p> |
