This invention relates to novel compounds of high antimicrobial activity of the formula: ##STR1## wherein R.sup.1 is carboxy(lower)alkyl or protected carboxy(lower)alkyl, R.sup.2 is carboxy or protected carboxy, R.sup.3 is hydrogen or lower alkyl, and R.sup.4 is lower alkyl, lower alkoxy, acyloxymethyl, lower alkylthiomethyl, lower alkoxymethyl, halogen, lower alkenyl or hydrogen, and pharmaceutically acceptable salts thereof, and processes for making the same.
本发明涉及高抗微
生物活性的新化合物,其
化学式为:##STR1##其中R.sup.1是羧基(较低)烷基或保护羧基(较低)烷基,R.sup.2是羧基或保护羧基,R.sup.3是氢或较低烷基,R.sup.4是较低烷基,较低烷氧基,酰氧甲基,较低烷
硫基甲基,较低烷氧甲基,卤素,较低烯基或氢,以及其药学上可接受的盐,并提供其制备方法。