| 摘要 |
A compound of the formula or its pharmaceutically acceptable salt: …<CHEM>… wherein… R<1> is hydrogen, lower alkyl or lower alkoxylphenyl,… R<2> is hydrogen or lower alkyl,… R<3> and R<5> are each hydrogen, or together to form a bond for getting a group of the formula: …<CHEM>… wherein R<4> and R<6> are each as defined below,… R<4> is lower alkyl,… R<6> is hydrogen or lower alkyl,… R<7> is hydrogen or a certain group, and… R<1><0> is hydrogen or lower alkyl which may have carboxy or esterified carboxy, processes for its preparation and pharmaceutical compositions containing it as an effective ingredient. |
