Phosphorus oxychloride → 7-(2-Methoxyimino-3-oxo-4,4-dibromobutyramido)-3-hydroxycepham-4-carboxylic acid

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Reaction Steps

A solution of 2-methoxyimino-3-oxo-4,4-dibromobutyric acid (syn isomer, 10 g) in methylene chloride (10 ml) was added to a solution of N,N-dimethylformamide (2.89 g) and phosphoryl chloride (6.07 g) in methylene chloride (30 ml) at -15° to 10° C., and stirred for an hour. The solution was added to a solution of 7-amino-3-hydroxycepham-4-carboxylic acid (4.8 g) and trimethylsilylacetamide (23.1 g) in methylene chloride (100 ml) at -15° to -10° C., and stirred for 2 hours. To the resultant solution was added water (40 ml) under ice-cooling and stirred for 10 minutes, and then the solvent was removed under reduced pressure therefrom. To the residue was added a saturated aqueous solution of sodium chloride (40 ml) and allowed to stand in a refrigerator overnight. The precipitates were collected by filtration, washed with a saturated aqueous solution of sodium chloride and water in turn, and dried under reduced pressure to give 7-(2-methoxyimino-3-oxo-4,4-dibromobutyramido)-3-hydroxycepham-4-carboxylic acid (syn isomer, 10.27 g).

Provenance & Evidence