NEUE ORGANISCHE VERBINDUNGEN UND VERFAHREN ZU DEREN HERSTELLUNG

A process for the production of 2,5-substituted thiadiazoles of formula I, **(See formula)** wherein R1 is hydrogen, fluorine, chlorine or trifluoromethyl, R2 is hydrogen, fluorine or chlorine, and **(See formula)** where R3 is an alkyl group containing 1 to 4 carbon atoms, n is 1, 2, 3 or 4, and m is 1, 2 or 3, with the proviso that (a) when R1 is trifluoromethyl, the two trifluoromethyl groups are not linked to adjacent carbon atoms, and b) when R1 is trifluoromethyl, R2 is hydrogen, characterized in that it reacts a compound of formula II, **(See formula)** wherein R1, R2, z and the condition are as previously defined, with Lewis acid under strong conditions, employing a medium containing a strong mineral acid, for example phosphoric, hydrochloric or sulfuric acid, or an oxyhalide or phosphorous halide, for example phosphorous tribromide, at temperatures between 40 and 100ºC, preferably between 50 and 65ºC, for a time between 1/2 and 20 hours, preferably between 2 and 6 hours. (Machine-translation by Google Translate, not legally binding)