Hydrochloric Acid → Chloro-N,N-dimethylformiminium chloride

Participants

Reaction Conditions

Reaction Steps

The solution of Vilsmeier reagent was prepared from dry N,N-dimethylformamide (0.4 g), phosphoryl chloride (0.8 g) and dry ethyl acetate (1.6 ml) in a usual manner. To the solution were added dry tetrahydrofuran (18 ml) and 2-(2-cyclopenten-1-yl)oxyimino-2-(2-formamidothiazol-4-yl)acetic acid (syn isomer) (1.2 g) and then stirred at -3° to 3° C. (Solution A). A mixture of 7-amino-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (1.5 g), sodium carbonate (0.9 g) and water (9.0 ml) was stirred to give a homogeneous solution. After the addition of acetone (9.0 ml), the solution was cooled to -3° C. and then thereto was added Solution A over a period of 5 minutes, keeping the temperature at -3° to 3° C. and the pH at 7.5 to 8.5 with triethyl amine. The resulting mixture was stirred for 30 minutes at the same temperature and pH. To the reaction mixture were added water, ethyl acetate and tetrahydrofuran. The resulting mixture was adjusted to pH 2.0 with 10% hydrochloric acid and filtered. The organic layer was separated from the filtrate, washed with water (×3), dried over magnesium sulfate, treated with activated charcoal and then evaporated. The residue was pulverized in isopropyl ether. The powder was collected by filtration, washed with isopropyl ether and then dried to give 7-[2-(2-cyclopenten-1-yl)oxyimino-2-(2-formamidothiazol-4-yl)acetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (1.83 g).

Provenance & Evidence