Process for the production of 4,5-disubstituted thiazoles

Claim 1

A process for the manufacture of a 3-amino-thiazolo-(4,5-c)-isothiazole of the formula ##STR15## where R 1 is hydrogen, alkyl of 1 to 6 carbon atoms, aralkyl of 7 to 12 carbon atoms, phenyl, ##STR16## the individual radicals R 2 are identical or different and each is alkyl of 1 to 6 carbon atoms, aralkyl of 7 to 12 carbon atoms or phenyl, the two radicals R 2 present as substituents of the nitrogen atom may also form, together with the latter, a 5-membered or 6-membered heterocyclic ring, which in addition to the nitrogen atom may also contain an oxygen atom, wherein the above radicals and rings may in addition be substituted by alkyl or alkoxy each of 1 to 4 carbon atoms, which process comprises: in a first step, reacting a 4-amino-5-cyanothiazole of the formula ##STR17## where R 1 has the above meaning, with hydrogen sulfide in the presence of at least one basic compound selected from the group consisting of alkaline earth metal compounds, alkali metal compounds, ammonium compounds, tertiary amines, primary amines or secondary amines, and, in a second stage, cyclizing the resulting 4-amino-5-thiocarbamido-thiazole of the formula ##STR18## where R 1 has the above meaning, in the presence of a dehydrogenating agent.