Process for the preparation of azo dyes
US4243583A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 25, 1979 |
| Grant date | Jan 6, 1981 |
| Priority date | — |
| Expiry date | May 25, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B43/003
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the preparation of azo dyes of the formula ##STR1## or mixtures thereof, in which Ar is a substituted or unsubstituted phenyl, naphthyl or aromatic heterocyclic radical and Y is a group of the formula --O-R, --S-R or ##STR2## in which R is a substituted or unsubstituted alkyl, aryl or heterocyclic radical and R.sub.1 and R.sub.2 independently of one another are hydrogen or a substituted or unsubstituted alkyl, aryl or heterocyclic radical, and the groups R.sub.1 and R.sub.2, together with the nitrogen atom to which they are bonded, can form a ring. The process comprises first coupling dimeric malonodinitrile with a diazo component and cyclizing the resulting intermediate with an alcohol, thioalcohol or amine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.