Process for the preparation of benzotriazole derivatives

US4999433A · kind A · utility

Assignee

• Ciba-Geigy · US

Inventors

• Helmut Prestel · Bruchsal, DE
• Klaus Muller · Meckenbeuren, DE

Key dates

• Filing date: Sep 26, 1989
• Grant date: Mar 12, 1991
• Expiry date: Sep 26, 2009

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07D249/20
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Hologenated 2-(2-hydroxyphenyl)-2H-benzotriazoles of the formula ##STR1## in which X is halogen, R.sub.1 is hydrogen, C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.6 cycloalkyl, phenyl or phenyl-C.sub.1 -C.sub.4 alkyl and R.sub.2 is C.sub.1 -C.sub.12 alkyl, C.sub.5 -C.sub.6 cycloalkyl, phenyl, phenyl-C.sub.1 -C.sub.4 alkyl or a group --C.sub.n H.sub.2n --COOR.sub.3, in which n is 0 to 4 and R.sub.3 is hydrogen or C.sub.1 -C.sub.12 alkyl, can be prepared particularly advantageously by catalytic hydrogenation of a corresponding o-nitroazo compound in the presence of a hydrogenation catalyst consisting of 0.1 to 3% of Pt on a support and of an organic amine.