Patent ID: 7179801

Claim:
A compound of the formula: wherein A is lower alkylene or lower alkenylene; R 1 is lower alkyl, hydroxy(lower)alkyl, protected hydroxy(lower)alkyl in which the hydroxy group is protected with an acyl group or an aryl(lower)alkyl group, amino(lower)alkyl or an amino(lower)alkyl in which the amino group is protected by an acyl group or a substituted or unsubstituted aryl(lower)alkyl group, and R 2 is hydrogen or an amino protecting group selected from the group consisting of an acyl group or a substituted or unsubstituted aryl(lower)alkyl group, or R 1 and R 2 are bonded together and form lower alkylene; R 3 and R 5 are, independently, amino or amino protected with an acyl group or a substituted or unsubstituted aryl(lower)alkyl group; and R 4 is carboxy or esterified carboxy, or a pharmaceutically acceptable salt thereof.