Preparation of 3,6-disubstituted 4-amino-1,2,4-triazin-5-ones

US4408044A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Thomas Schmidt · Neustadt, DE
• Helmut Timmler · Wuppertal, DE
• Gerhard Bonse · Neunburg vorm Wald, DE
• Heinz U. Blank · Odenthal, DE
• Gerhard Marzolph · Cologne, DE

Key dates

• Filing date: Jan 11, 1982
• Grant date: Oct 4, 1983
• Expiry date: Jan 11, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D253/07
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The herbicidal 3,6-substituted 4-amino-1,2,4-triazin-5-one of the general formula ##STR1## wherein R.sup.1 and R.sup.2 have the meaning given in the description, is obtained in good yields by a new two-stage cyclization reaction if an .alpha.-ketocarboxylic acid amide of the general formula EQU R.sup.1 --CO--CO--NHR.sup.3 (II) is reacted with a hydrazidine of the general formula ##STR2## if appropriate in the presence of a diluent at temperatures between 0.degree. and 150.degree. C., whereby in the first process stage a condensation reaction takes place to give condensation products which still have open chains, and in the second process stage an elimination reaction with ring closure takes place to give the end product of formula (I).