Dimethylformamide → Ethyl 2-(bromoethoxyimino)-2-(2-tritylamino-4-thiazolyl)-acetate

Participants

Reaction Conditions

Reaction Steps

4.14 g of potassium carbonate were added over 3 minutes under argon at room temperature to a mixture of 4.94 g of syn isomer of ethyl 2-(2-tritylamino-4-thiazolyl)-2-hydroxyimino-acetate hydrochloride and 10 ml of dimethylformamide, and after stirring the mixture at 20° C. for 20 minutes, 8.65 ml of 1,2-dibromoethane were added thereto. The mixture was stirred for 30 hours and was poured into 100 ml of distilled water and 20 ml of methylene chloride. The mixture was decanted and the aqueous phase was extracted with methylene chloride. The combined organic phases were dried and vacuum filtered. The filter was rinsed and the filtrate was evaporated to dryness to obtain a raw product which was chromatographed over silica gel. Elution with benzene containing 5% of ether yielded a first fraction which was crystallized from methanol after dissolution at 50°-60° C. Vacuum filtration at 0° to 5° C. yielded 1.16 g of the syn isomer of ethyl 2-(2-tritylamino-4-thiazolyl)-2-(2-bromoethoxyimino)-acetate in the form of a white cream product melting at 117° C. Next obtained was a homogenous fraction of 1.258 g of product.

Provenance & Evidence