Isothiazoles, halogeno

Simple isothiazole-4-carboxylic acids have been made from the corresponding nitriles, which are available in turn from the halogeno derivatives, or directly by the olefin route.5-Aminoiso-thiazole-4-esters and -nitriles are readily obtained by the thioamide route. The 4-acids behave normally and form acid chlorides, esters, amides, and hydrazides. In contrast to the 5-series... 

The weU-known synthesis from 3-halogeno-a, -imsaturated aldehydes 1 and ammonium thiocyanate, via intermediate 2, is very useful for the preparation of substituted isothiazoles 3 and for fused analogues (Scheme 1, Method A) [1,2]. 

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