Synthesis of pyrazole dyes
US5144015A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 31, 1991 |
| Grant date | Sep 1, 1992 |
| Priority date | — |
| Expiry date | Jul 31, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B29/0037
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A process for preparing a 1-alkyl-3-secondary or tertiary alkyl-4-cyano-pyrazol-5-yl azo dye or a 1-alkyl-3-aryl-4-cyano-pyrazol-5-yl azo dye comprising: PA0 a) reacting a 3-secondary or tertiary alkyl-4-cyano-5-amino pyrazole or a 3-aryl-4-cyano-5-amino pyrazole with a diazotizing reagent to form a pyrazol-5-yl diazonium salt; PA0 b) allowing said diazonium salt to react with an aromatic coupling component to form a 3-secondary or tertiary alkyl-4-cyano-pyrazol-5-yl azo dye or a 3-aryl-4-cyano-pyrazol-5-yl azo dye; and PA0 c) reacting the product of step b) with an aklylating agent in the presence of a base to form a 1-alkyl-3-secondary or tertiary alkyl-4-cyano-pyrazol-5-yl azo dye or a 1-alkyl-3-aryl-4-cyano-pyrazol-5-yl azo dye.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.