Preparation of 4-amino-6-tert.-butyl-3-alkylthio-1,2,4-triazin-5-(4H)-ones

Abstract

Abstract In the preparation of 4-amino-6-tert.-butyl-3-methylthio-1,2,4-triazin-5-(4H)-one of the formula ##STR1## wherein pivaloyl cyanide of the formula (CH.sub.3).sub.3 C--CO--CN is reacted to form an intermediate, the intermediate is condensed with thiocarbohydrazide of the formula NH.sub.2 --NH--CS--NH--NH.sub.2 to form 4-amino-6-tert.-butyl-3-mercapto-1,2,4-triazin-5-(4H)-one of the formula ##STR2## and the 4-amino-6-tert.-butyl-3-mercapto-1,2,4-triazin-5-(4H)-one is alkylated to replace the H atom on the sulphur by --C 1-4 --alkyl, the improvement which comprises reacting the pivaloyl cyanide with a carboxylic acid anhydride of the formula R--CO--O--CO--R in which R is an optionally substituted aliphatic radical with up to 8 carbon atoms or an optionally substituted phenyl radical, in the presence of a strong acid at a temperature between about -50° and +150° C., and then directly reacting the reaction mixture thus obtained with the thiocarbahydrazide. Advantageously R is CH 3 , the strong acid is concentrated sulphuric acid, the pivaloyl cyanide is effected at a temperature between about 0° and 100° C., the condensation with thiocarbohydrazide is effected, in the presence of a mineral acid, in an aqueous or aqueous-alcoholic medium, and the alkylation is effected using methyl iodide or methyl bromide in the presence of sodium hydroxide at about 0° to 50° C.

Inventors

• 👤 Gerhard Bonse
• 👤 Heinz U. Blank
• 👤 Hans Kratzer

Bibliographic Details