One-pot synthesis of pyrazolotriazole photographic dye forming color couplers and coupler intermediates

摘要

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.