Patent ID: 6034245
Filing Date: 2000-03-07
Classification: C07D,Y02P

Abstract:
A process of making 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole comprising the steps of:(a) reacting methyldithiocarbazinate with trifluoroacetic acid in the absence of phosphorus trichloride to form a mixture of 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole and 2,5-bis-(methylthio)-1,3,4-thiadiazole, wherein the molar ratio of methyldithiocarbazinate to trifluoroacetic acid is from about 4:1 to about 1:5, and wherein the mixture contains a first organic phase and a first aqueous phase;(b) separating the first organic phase and the first aqueous phase;(c) acidifying the first organic phase with a concentrated inorganic acid, resulting in the formation of a second organic phase and a second aqueous phase, wherein the 2,5-bis-(methylthio)-1,3,4-thiadiazole is soluble in the second aqueous phase; and(d) separating the second organic phase and the second aqueous phase, wherein the 2,5-bis-(methylthio)-1,3,4-thiadiazole remains in the second aqueous phase.