| 摘要 |
7 beta -Amino-3-cephem-3-cl-4-carboxylic acid compounds of the formula <IMAGE> (IA) wherein R1a represents hydrogen or an amino protective group R1A and R1b represents hydrogen or an acyl group Ac, or R1a and R1b together represent a bivalent amino protective group, R2 represents hydroxyl or a radical R2A which together with the carbonyl grouping -C(=O)- forms a protected carboxyl group and R3 represents hydrogen, lower alkyl or a hydroxyl protective group, and 1-oxides of 3-cephem compounds of the formula IA, and the corresponding 2-cephem compounds are prepared in that a compound of the formula <IMAGE> (II) wherein R1a, R1b and R2A have the meanings mentioned under formula IA, R3o represents lower alkyl or a hydroxyl protective group and Y represents a group which is removed, is treated with a base; also comprised are intermediate products.
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