| 摘要 |
NEW MATERIAL:A compound of formulaI[R<1> is arylmethyl, aryloxymethyl; R<2> is lower alkyl, arylmethyl, which may be substituted with halogen; R<3>, R<4> are lower alkyl, phenyl]. USE:Synthetic intermediate of cephalosporins, antibiotics. PREPARATION:An azetidinone derivative of formula II and a phosphite ester of formula III (R<5> is lower alkyl, phenyl) such as trimethyl phosphite are allowed to react, preferably at a molar ratio of 1/(1.5-3) in an inert solvent such as benzene at -20-100 deg.C. |
