| abstract |
This refers to a compound of the formula (1), wherein: A is lower alkylene or lower alkenylene; R1 is lower alkyl, hydroxy (lower) alkyl, hydroxy (lower) protected alkyl, amino (lower) alkyl or amino (lower) protected alkyl, and R2 is hydrogen or amino protecting group, or R1 and R2 are linked together and they form lower alkylene; R3 and R5 are independently amino or protected amino; and R4 is protected carboxy or carboxy, or a pharmaceutically acceptable salt thereof, a process for preparing a compound of the formula (1), and a pharmaceutical composition comprising a compound of the formula (1) mixed with a pharmaceutically carrier or carrier. acceptable. |