Sulfuric Acid → 7-(2-Methoxyimino-3,3-diethoxy-4-bromobutyramido)-3-cephem-4-carboxylic acid

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Reaction Conditions

Reaction Steps

Acetic anhydride (27.3 ml) was added to a solution of 7-(2-methoxyimino-3,3-diethoxy-4-bromobutyramido)-3-hydroxycepham-4-carboxylic acid (syn isomer, 30 g) in dry tetrahydrofuran (300 ml) at room temperature and stirred at 28° C. for 30 minutes. After adding sodium acetate (4.0 g) and potassium acetate (4.7 g) to the solution, the solution was stirred at 28° to 30° C. for 3 hours. The resultant solution was added to a solution of ethyl acetate (300 ml) and a saturated aqueous solution of sodium chloride (300 ml), and adjusted to pH 2.0 with 20% sulfuric acid. After separating the organic layer, the aqueous layer was extracted with ethyl acetate (100 ml) twice. The organic layer and the extract were combined, washed with a saturated aqueous solution of sodium chloride, and then dried over magnesium sulfate. After treating the solution with activated charcoal, the solution was evaporated in vacuo. n-Hexane was added to the residue and decanted to give the oil (35.1 g) of 7-(2-methoxyimino-3,3-diethoxy-4-bromobutyramido)-3-cephem-4-carboxylic acid (syn isomer).

Provenance & Evidence