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

US4315094A · 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: Feb 9, 1982
• Expiry date: Feb 19, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In the preparation of 4-amino-6-tert.-butyl-3-alkylthio-1,2,4-triazin-5-(4H)-one of the formula ##STR1## wherein (1) pivaloyl cyanide of the formula EQU (CH.sub.3).sub.3 C--CO--CN is reacted to form a derivative of pyruvic acid, (2) the pyruvic acid derivative 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 (3) this is alkylated, the improvement which comprises effecting step (1) by reaction 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 adding water to the reaction mixture, thereby to form trimethylpyruvic acid N-acylamide of the formula EQU (CH.sub.3).sub.3 C--CO--CO--NH--CO--R.