Dichloroacetyl chloride → HCID 178524650, compound

Participants

Reaction Conditions

Reaction Steps

7-Amino-3-(1H-1,2,3-triazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (0.98 g) was suspended in methylene chloride (10 ml) and bis(trimethylsilyl)acetamide (2.53 g) was added to the suspension to give a solution. To the solution was added dropwise a solution of dichloroacetyl chloride (0.46 g) in methylene chloride (10 ml) at -30° C. The mixture was stirred at -10°0 to -15° C for 30 minutes and then concentrated under reduced pressure. To the residue was added ethyl acetate (50 ml) and water (30 ml) and the mixture was stirred and filtered. The ethyl acetate layer was separated from the filtrate and concentrated under reduced pressure to a half of volume. Water (30 ml) was added to the concentrated solution and the mixture was adjusted to pH 7.2 by adding aqueous sodium bicarbonate under cooling and stirring. The aqueous layer was separated from the mixture, adjusted to pH 6 with diluted hydrochloric acid, washed with ethyl acetate, adjusted to pH 2 with diluted hydrochloric acid and then extracted with ethyl acetate. The extract was washed with saturated aqueous sodium chloride, dried over magnesium sulfate and treated with activated charcoal powder. Ethyl acetate was distilled off from the solution under reduced pressure. The residue was pulverized by treating with ether and precipitates were collected by filtration to give 7-dichloroacetamido-3-(1H-1,2,3-triazol-5-ylthiomethyl)-3-cephem-4-carboxylic acid (0.56 g). The solvent was distilled off from the mother liquid under reduced pressure and the residue was pulverized by treating with diisopropyl ether. Precipitates were collected by filtration to give the same product (0.14 g). Total yield was 0.70 g.

Provenance & Evidence