1,3-Bis(trimethylsilyl)urea → Benzhydryl 7-[2-allyloxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetamido]-3-mesyloxy-3-cephem-4-carboxylate

Participants

Reaction Steps

To a solution of benzhydryl 7-amino-3-mesyloxy-3-cephem-4-carboxylate (6.91 g) and bis(trimethylsilyl)urea (18.4 g) in methylene chloride (69 ml) was added 2-allyloxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetyl chloride hydrochloride (syn isomer) (4.08 g) at -10° C. under stirring and the mixture was stirred at the same temperature for 30 minutes. After the reaction mixture was added to a stirred mixture of water and methylene chloride, the solution was adjusted to pH 7.0 with a saturated aqueous solution of sodium bicarbonate. The separated organic layer was washed with brine, dried over magnesium sulfate and evaporated in vacuo to give benzhydryl 7-[2-allyloxyimino-2-(5-amino-1,2,4-thiadiazol-3-yl)acetamido]-3-mesyloxy-3-cephem-4-carboxylate (syn isomer) (8.90 g).

Provenance & Evidence