| 摘要 |
<p>PURPOSE:To effectively obtain the compound useful as an intermediate for an antibacterial agent by a new method in which ring-closure reaction of beta- lactam compound and a phosphate reaction are performed in one-pot reaction. CONSTITUTION:The compound of formula III (L is an arylsulfonyloxy, a lower- alkanesulfonyloxy, etc.) is obtained by reacting a beta-lactam compound of formula I (R1, R2 are each H or a lower alkyl; R3 is a lower alkyl; X is H or a protected hydroxyl; COZ is an active ester of a carboxyl group, an arylthiocarbonyl, etc.) {e.g. (3S,4S)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-4-[(1R)-1- imidazolylcarbonylethyl]-2-azetidinone} with an acetic acid ester derivative of formula II (R4 is a carboxyl-protecting group; Y is an active ester of a hydroxyl group or a halogen) (e.g. methyl bromoacetate) in the presence of a base (preferably, sodium hydroxide) followed by the treatment of the reaction product with an active esterification reagent for a hydroxyl group (e.g. methanesulfonic anhydride).</p> |
