| 摘要 |
<p>Thiazolinoazetidinone compounds, which are useful as intermediates in the preparation of cephalosporins, have the formula:- <IMAGE> wherein R is hydrogen, methoxy, C1-C2 alkoxycarbonyl, C1-C8 alkyl, C1-C8 alkyl monosubstituted with protected hydroxy, C1-C3 alkoxy or cyano, C2-C8 alkenyl, C2-C8 alkenyl monosubstituted with protected hydroxy, C1-C3 alkoxy or cyano, C3-C8 cycloalkyl, C3-C8 cycloalkyl substituted with protected hydroxy, C1-C3 alkoxy or cyano, <IMAGE> R<2> is hydrogen, protected hydroxy, chloro, bromo, C1-C3 alkyl, C1-C3 alkoxy, nitro or cyano; Y is oxygen or a carbon-carbon bond; R<3> is protected hydroxy, C1-C4 alkyl or protected amino; m is 0-2; n is 0-2; R<1> is a carboxylic acid protecting group; provided that the 1-and 5- position C-H bonds in the resulting thiazolinoazetidinone are in the alpha - position. The compounds are prepared by an allylic chlorination process from an appropriate 3-methyl-2-but-3-enoate.</p> |
