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

Abstract

In the preparation of 4-amino-6-tert.-butyl-3-alkylthio-1,2,4-triazin-5(4H)-ones of the formula ##STR1## wherein (a) pivaloyl cyanide of the formula (CH.sub.3).sub.3 C--CO--CN is converted to a derivative of trimethylpyruvic acid, (b) the derivative is condensed with thiocarbohydrazide of the formula H.sub.2 N--NH--CS--NH--NH.sub.2 to form 4-amino-6-tert.-butyl-3-mercapto-1,2,4-triazin-5(4H)-one, and (c) that is alkylated to form the indicated end products, the improvement which comprises effecting (a) by reacting the pivaloyl cyanide with a strong anhydrous inorganic acid at about -50.degree. to +50.degree. C. thereby to form trimethylpyruvic acid amide. The derivative in (a) can be trimethylpyruvic acid amide or it may first be saponified to the free acid. The inorganic acid in (a) can be hydrochloric or hydrobromic acid in glacial acetic acid, or it can be concentrated sulphuric acid plus some chloride ion and followed by water. Trimethyl pyruvic acid amide is a new compound.

Dependencies are inferred from the claim text.