Nucleophilic SN2 displacements on penicillin-6- and cephalosporin-7- triflates; 6β-iodopenicillanic acid, a new β-lactamase inhibitor
作者:John E.G. Kemp、Michael D. Closier、Subramanian Narayanaswami、Mark H. Stefaniak
DOI:10.1016/0040-4039(80)88017-8
日期:1980.1
Triflate or nonaflate esters of alkyl 6α (or β) hydroxypenicillanates are substituted (with inversion) by the soft nucleophiles iodide, bromide, chloride, azide, arylselenoxide,1 thiocyanate, thiols, and thiolacids; carbon nucleophiles fail. Methoxide (hard) attacks the lactam bond, opening both rings to give a known11 1,4 thiazine. Iodide substitutes 7α-trifloxycephalosporins, giving 7β-iodocephalosporins
烷基6α(或β)羟基青霉酸酯的三氟甲磺酸酯或壬酸酯,被柔软的亲核试剂碘化物,溴化物,氯化物,叠氮化物,芳基硒氧化物,1硫氰酸盐,硫醇和硫醇盐取代(有反相);碳亲核试剂失效。甲氧化物(硬)攻击内酰胺键,打开两个环,得到一个已知的11 1,4噻嗪。碘化物替代7α-三氟头孢菌素,得到7β-碘头孢菌素。