The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 26, 1991
Filed:
Aug. 23, 1989
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
A process for the preparation of azo dyes of the formula ##STR1## in which X is --NH.sub.2 or --OH, A is a benzene or naphthalene radical which can be substituted by nitro, halogen, sulfo, C.sub.2 -C.sub.6 alkanoylamino, C.sub.1 -C.sub.6 -alkoxycarbonylamino, sulfonamido and sulfone groups and B is a benzene radical which is monosubstituted or disubstituted by C.sub.1 -C.sub.6 alkyl, or a naphthalene radical which can be substituted by amino, phenylamino, C.sub.1 -C.sub.6 alkylamino and sulfo, or a 1-phenyl-3-methyl-5-pyrazlone radical which can be substituted by halogen, C.sub.1 -C.sub.6 alkyl and C.sub.1 -C.sub.6 alkoy, these radicals being bound to the azo group in the o-position with respect to the hydroxyl or amino groups, comprises diazotizing in aqueous solution an amine of the formula ##STR2## in the presence of at least one ketone of the formula ##STR3## in which R.sub.1 and R.sub.2, independently of one another, are each C.sub.1 -C.sub.4 alkyl, and coupling the product on to a coupling component of the formula ##STR4## in which A, B and X in formulae (2) and (4) are as defined in formula (1). The present invention makes it possible to prepare the azo dyes mentioned in high yields.