反应详情

Thiourea (0.18 g.) was added to a suspension of 4-nitrobenzyl 7-[2-(2-bromoacetyl)-2-hydroxyiminoacetamido]-3-cephem-4-carboxylate (syn-isomer: 1.05 g.) in ethanol (25 ml.), tetrahydrofuran (25 ml.) and water (5 ml.), and stirred at room temperature for 4 hours. The resultant solution was concentrated under reduced pressure and cooled. The residue was crystallized by treating with a mixture of tetrahydrofuran and ethyl acetate, and collected by filtration to give 4-nitrobenzyl 7-[2-(2-amino-4-thiazolyl)-2-hydroxyiminoacetamido]-3-cephem-4-carboxylate (syn-isomer: 0.95 g.), colorless crystals, mp 172° to 175° C. (dec.)

1. concentrationThe resultant solution was concentrated under reduced pressure
2. temperaturecooled
3. customThe residue was crystallized
4. additionby treating with a mixture of tetrahydrofuran and ethyl acetate
5. filtrationcollected by filtration