One-pot synthesis of pyrazolotriazole photographic dye forming color couplers and coupler intermediates
US5969148A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1998 |
| Grant date | Oct 19, 1999 |
| Priority date | — |
| Expiry date | Dec 2, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D487/04
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Photographic pyrazolotriazole dye forming coupler compounds of coupler intermediate compounds can be readily prepared in a single reaction medium by reacting certain pyrazolotriazole compounds with nitro-substituted aromatic compounds in the presence of a formate salt and a transition metal catalyst. This salt hydrogenates the nitro group and the carbonate by-product induces reaction of the resulting amine with the pyrazolotriazole compound. Yields and purity are high, and reaction time is reduced with the specific set of conditions and reactants, and environmental impact from waste is reduced. In addition, isolation of aromatic amine intermediates is avoided. The resulting pyrazolotriazole compounds can be used themselves as photographic dye forming couplers or further reacted to prepare useful coupler compounds for photographic use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.