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

US4328340A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gerhard Bonse · Neunburg vorm Wald, DE
• Heinz U. Blank · Odenthal, DE
• Hans Kratzer · Wuppertal, DE

Key dates

• Filing date: Feb 19, 1981
• Grant date: May 4, 1982
• Expiry date: Feb 19, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D253/075
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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 EQU (CH.sub.3).sub.3 C--CO--CN is reacted to form an intermediate, the intermediate is condensed with thiocarbohydrazide of the formula EQU 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.sub.1-4 --alkyl, the improvement which comprises reacting the pivaloyl cyanide with a carboxylic acid anhydride of the formula EQU 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.degree. and +150.degree. C., and then directly reacting the reaction mixture thus obtained with the thiocarbahydrazide. Advantageously R is CH.sub.3, the strong acid is concentrated sulphuric acid, the pivaloyl cyanide is effected at a temperature between about 0.degree. and 100.degree. C., the condensation with thiocarbohy…