Isothiazole aldehydes and ketones

In general, the properties of these compounds and those of their benzenoid analogues are similar. Thus, isothiazole aldehydes and ketones behave normally and form the usual derivatives. Imidazole-2-carbaldehyde exists as a hydrate in aqueous solution. 4-Acetyloxazoles are oxidized to the corresponding acids with sodium hypobromite. Thiazole aldehydes undergo the benzoin and Cannizzaro reactions. Compounds with aldehyde groups to an NH group sometimes form dimers, e.g., as in the 1,2,4-triazole series 615. 

Isothiazoles.1 These heterocycles can be prepared by reaction of a-acetylenic aldehydes or ketones with hydroxylamine-O-sulfonic acid and then with sodium hydrosulfide in a buffered aqueous solution. 

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