| 摘要 |
NEW MATERIAL:The compound of formula I [R1 is vinyl, hydroxymethyl, formyl, aryl or group of formula II (X is O, S or NH); R2 is H or carboxyl- protecting group; R3 is H or hydroxyl-protecting group]. EXAMPLE:4-Carboxy-3-(1-hydroxyethyl)-1-allyl-2-azetidinone. USE:Useful as an intermediate for various carbapenem derivative having antibacterial activity. PREPARATION:The compound of formula I can be produced by reacting the Schiff base of formula II with a diketene in the presence of imidazole in an inert solvent, reducing the acetyl group of the resultant 3-acetyl-2-azetidinone-4- carboxylic acid ester derivative of formula III and, if necessary, removing the carboxyl-protecting group R2 or protecting the hydroxyl group. |
