反应详情

Trifluoroacetic anhydride (1 ml.), anisole (1 drop) and dimethylformamide (1 drop) were added to a solution of 7-(2-methoxyimino-3-oxo-4-bromobutyramido)-3-hydroxycepham-4-carboxylic acid (syn isomer, 1 g.) in dry tetrahydrofuran (3 ml.) and stirred for 4 hours. After adding methanol (0.3 ml.) into the resultant solution, the solution was stirred for an hour and concentrated in vacuo. The residue was pulverized with diisopropyl ether. The precipitates were collected by filtration and dried over phosphorus pentoxide to give 7-(2-methoxyimino-3-oxo-4-bromobutyramido)-3-cephem-4-carboxylic acid (syn isomer, 0.82 g).

1. stirringthe solution was stirred for an hour
2. concentrationconcentrated in vacuo
3. filtrationThe precipitates were collected by filtration
4. dry with materialdried over phosphorus pentoxide