Process for the preparation of arylidine dyes using an active methylene compound
US5214186A · kind A · utility
1Cited by
7References
8Claims
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Key dates
| Filing date | Dec 3, 1991 |
| Grant date | May 25, 1993 |
| Priority date | — |
| Expiry date | Dec 3, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B23/143
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for the preparation of arylidene dyes comprises the reaction of an aromatic amine with an enolate salt of a formylated active methylene compound in the presence of a sulfonyl halide compound. An enol sulfonate is postulated as a reactive intermediate in the reaction. The process gives high yields of products under mild reaction conditions and allows the use of aromatic groups containing substituents such as hydroxy that lead to side reactions and low product yields with previously known methods for making arylidene dyes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.