| 摘要 |
NEW MATERIAL:The compound of formula I (R1 is H or amino-protecting group; R2 is H or lower alkyl; R3 and R4 are H, sulfonic acid group or amino-protecting group). EXAMPLE:(3S)-3-Carbobenzoxyamino-1-phthalyl-2-azetidinone. USE:Intermediate of beta-lactam antibiotics. PROCESS:The compound of formula IV can be prepared e.g. by (1) reacting a serine derivative having protected amino group and hydroxyl group with a 1,1- N-protected hydrazine [(R5)(R6)N-NH2] in the presence of carbodiimide as a condensation agent, (2) carrying out the dehydrative cyclization of the resultant compound of formula II using a condensation agent such as triphenyl phosphine to obtain the compound of formula III, (3) removing the protecting groups R5 and R6 therefrom, and (4) reacting with sulfuric anhydride. |
