| 摘要 |
PURPOSE:To obtain a corresponding beta-lactam carboxylate in high yield, by deprotecting an alkyl protecting group of penicillin homologue at low temperature, subjecting it to salt exchange with an alkali metal, etc. CONSTITUTION:An aralkyl ester of beta-lactam carboxylic acid [e.g., a compound shown by the formula I (R<1> is aralkyl; R<2>, R<3>, and R<4> are substituent group in penicillin-cephalosporin chemistry; X is S, CH2, etc.; R<5> is alkyl which may exist)] is eliminated with a Lewis acid (e.g., halide of B, Mg, Al, etc.) and a carbonium cation scavenger (e.g., anisole, thiophenol, etc.) at <=-30 deg.C, the prepared salt is reacted with a salt of alkaline (earth) metal or ammonium or a hydroxide, to give a corresponding beta-lactam carboxylate {e.g., a compound shown by the formula II[M is H, alkaline (earth) metal atom]}. |
