The N-formamido cephalosporins 4a and4b undergo direct methoxylation at the Pα-position to give the 7α-methoxy derivatives 5a and 5b. These were converted to other 7β-acylamido compounds by the sequence : oxidation, deformylation, acylation and reduction. The 3-bromomethyl derivatives 2b,6b and 8b proved amenable to nucleophilic substitution with 5-mercapto-1-methyltetrazole.
N-甲酰胺基
头孢菌素4a和4b在Pα-位进行直接甲氧基化,得到7α-甲氧基衍
生物5a和5b。这些通过以下顺序被转化为其他7β-酰基酰胺基化合物:氧化,去甲酰基化,酰化和还原。证明3-
溴甲基衍
生物2b,6b和8b适合用5-巯基-1-
甲基四唑进行亲核取代。