Hydrochloric Acid → 2-Methoxyimino-2-(5-formamido-1,2,4-thiadiazol-3-yl)acetic acid

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Reaction Steps

A mixture of S-methyl (5-formamido-1,2,4-thiadiazol-3-yl)thioglyoxylate (231 mg) in methanol (2 ml) and 1 N-aqueous solution of potassium hydroxide (3.5 ml) was stirred for an hour at ambient temperature. The mixture was adjusted to pH 7.6 with 1 N hydrochloric acid, followed by an addition of O-methylhydroxylamine hydrochloride (90 mg) and stirring for 30 minutes at ambient temperature. The reaction mixture was neutralized with an aqueous solution of sodium bicarbonate and concentrated to remove methanol. The concentrated aqueous solution was adjusted to pH 4 with hydrochloric acid and washed with ethyl acetate. The aqueous layer was adjusted to pH 1 with hydrochloric acid, saturated with sodium chloride and extracted with ethyl acetate. The extract was evaporated to dryness and the residue was triturated with diethyl ether, collected by filtration and then dried to give the title compound (80 mg), mp. 185° to 186° C.

Provenance & Evidence