A compound represented by the formula: ##STR1## wherein R.sub.1 is hydrogen or methoxy; R.sub.2 is hydrogen or hydroxy; R is ##STR2## wherein R.sub.3 and R.sub.4 are hydroxy or acyloxy, Y is oxygen, sulfur or >N-R.sub.5 wherein R.sub.5 is hydrogen or lower alkyl, and Z is sulfur or >N-R.sub.5 wherein R.sub.5 has the same meanings as defined above; and X is ##STR3## wherein R.sub.6 is acyloxy or nitrogen-containing heterocyclicthio which may have substituent(s), a pharmaceutically accpetable salt thereof, and a carboxylic ester thereof. This compound has improved antibacterial activity against Kleb. pneumoniae and Pseud. aeruginosa.
一种化合物的
化学式为:##STR1##其中R.sub.1是氢或甲氧基;R.sub.2是氢或羟基;R是##STR2##其中R.sub.3和R.sub.4是羟基或酰氧基,Y是氧,
硫或>N-R.sub.5,其中R.sub.5是氢或较低的烷基,Z是
硫或>N-R.sub.5,其中R.sub.5具有上述定义的相同含义;X是##STR3##其中R.sub.6是酰氧基或含氮杂环
硫基,可以具有取代基,其药学上可接受的盐和
羧酸酯。该化合物对Kleb. pneumoniae和Pseud. aeruginosa具有改善的抗菌活性。