Compounds of the formula ##STR1## in which R is hydrogen or an acyl group, R.sub.1 is hydrogen or lower alkyl, and R.sub.2 is hydrogen, an alkali metal cation, or a readily removable ester forming group, are active antibiotics or intermediates thereto.
公式为##STR1##的化合物,其中R为氢或酰基,R.sub.1为氢或低碳烷基,R.sub.2为氢、碱
金属阳离子或易于去除的酯基团,是活性抗生素或其中间体。