Hydroxyamine hydrochloride → N-[(2,4-dichloro-1,3-thiazol-5-yl)methylidene]hydroxylamine

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Reaction Steps

First 153 g (2.2 mol) of hydroxylamine hydrochloride in portions, then a solution of 364 g (2 mol) of 2,4-dichloro-5-thiazolecarboxaldehyde (II) in 1 liter of ethanol are added to a solution of 185 g (2.2 mol) of sodium bicarbonate in 5 liters of water at room temperature, with stirring. A voluminous, colourless precipitate separates out after 1 to 2 minutes. After stirring for 1 hour, the solid is filtered off with suction, washed with water and dried. 390 g (=99% of theory) of 2,4-dichloro-5-thiazolecarboxaldehyde oxime (IV) of melting point about 160° C. are obtained. It can be dehydrated to give the nitrile without further purification.

Provenance & Evidence