| 摘要 |
PROBLEM TO BE SOLVED: To simply produce a compound useful as a synthetic intermediate for carbapenem-based compounds at a low cost. SOLUTION: This azetidinone derivative of formula I (R is a protecting group of hydroxyl group; R<1> is H or an alkyl; R<2> is a protecting group of carboxyl group; R<3> is an alkyl; R<4> is an aryl or an alkyl), e.g. (2R)-N- isopropyl-2- (3S,4R)-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-1-(4- nitrobenzyloxycarbonylmethyl)-1-oxoazetidin-4-yl}-N-phenylsulfonylprop ionamide. The derivative of formula I is obtained by adding and reacting a base (e.g. Na t-butoxide) in an equiv. amount to a haloacetic acid ester of the formula XCH2 COOR<2> (X is a halogen atom) with a solution of 1 equiv. azetidinone 4-alkyl derivative of formula II and preferably 1.2-1.5 equiv. haloacetic acid ester in an inert solvent (DMF, etc.), preferably at -50 to -40 deg.C for 2-3hr. |
