关键词: 紫外分光光度法, 烷氧基, 红外分光光度法, 质谱法, 质子磁共振谱法, 一元醇, 头孢霉素, 烷氧化反应

A mild method of introducing 7a-alkoxy in cephalosporins was developed. An electrophilic center was formed at the C-7 position of 7-substituted-azino-cephalosporins with the help of a nitro group via the conjugated system. The lower alkoxy groups (including C1-C3 alkyl and Bu) were stereoselectively introduced into the C-7a position under mild conditions from the corresponding alcs., in the presence of protic acids. tert-Bu alcohol and its higher homologs do not react. Twelve new benzyhydryl esters of 7a-alkoxy-7b-hydrazonocephalosporins I (R = H, OAc, methyltetrazolylthio; R1 = nitrophenyl, nitrothienyl, nitrofuryl; R2 = Me, Et, Pr, Me2CH, Bu) were synthesized, the structures of which were identified with UV, IR, 1H NMR and mass spectra.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, ALKOXYL GROUP, INFRARED SPECTROPHOTOMETRY, MASS SPECTROGRAPHY, PROTON MAGNETIC RESONANCE SPECTROMETRY, MONOHYDRIC ALCOHOL, CEPHALOSPORINS