3-Acetoxymethyl cephalosporin antibiotics in which the 7.beta.-acylamido group has the structure ##STR1## where R is thienyl, furyl or phenyl; R.sup.a is C.sub.1-4 alkyl, C.sub.2-4 alkenyl, C.sub.3-7 cycloalkyl or phenyl, and R.sup.b is hydrogen, carboxy, C.sub.2 -C.sub.5 carbalkoxy or any of the groups designated for R.sup.a, or R.sup.a and R.sup.b together with the carbon atom to which they are attached form a C.sub.3-7 cycloalkylidene or cycloalkenylidene group; exhibit broad spectrum antibiotic activity characterized by particularly high activity against gram negative microorganisms, including those which produce .beta.-lactamases. The compounds, which are syn isomers or exist as mixtures of syn and anti isomers containing at least 90% of the syn isomer, have particularly high in vitro activity against strains of Escherichia coli. Haemophilus influenzae and Proteus organisms; and also shown unusually high activity against Pseudomonas organisms.
这种3-乙酰氧甲基
头孢菌素抗生素,其中7-β-酰胺基团具有结构##STR1## 其中R是
噻吩基、
呋喃基或苯基;R.sup.a是C.sub.1-4烷基、C.sub.2-4烯基、C.sub.3-7环烷基或苯基,R.sup.b是氢、羧基、C.sub.2-C.sub.5羰基酯或R.sup.a指定的任何基团,或R.sup.a和R.sup.b与它们连接的碳原子一起形成C.sub.3-7环烷基亚甲基或环烯基亚甲基团;表现出广谱抗生素活性,特别是对革兰氏阴性微
生物具有极高的活性,包括那些产生β-内酰胺酶的。这些化合物是同构体或存在至少90%同构体的同和反异构体的混合物,对大肠杆菌、流感嗜血杆菌和变形杆菌菌株表现出特别高的体外活性;并且还表现出对
铜绿假单胞菌具有异常高的活性。