Eastman-kodak Company

Hamish McNab

Bernard A Clark

Craig Cameron Sommerville

David T Clarke

Robert N Gourley

Richard W Mares

The invention provides a method of transforming a pyrazole compound, comprising cyclizing a 1,5-diaminopyrazole compound having the structure: ##STR1## wherein R.sup.1 is a substituent group; and X is hydrogen, an acyl group, or a heterogroup; in an alkaline solution with carbon disulphide to produce a pyrazolotriazole thione compound having formula (3). ##STR2##

Method of transforming pyrazole compounds

The invention provides a photographic element comprising a light-sensitive silver halide emulsion layer having associated therewith a dye-forming coupler of formula (I): ##STR1## wherein X is H or a coupling-off group, R.sub.1 is H or a substituent group; Y and Z are the same or different and are H or are independently selected from alkyl, aryl and heteroaryl groups; provided that Y and Z taken together with the nitrogen atom may form a 5-10 membered heterocyclic ring.

Photographic elements containing certain yellow dye-forming couplers

The present invention provides a photographic element comprising a silver halide emulsion layer having associated therewith a dye-forming coupler of formula (I): ##STR1## wherein X is H or a coupling-off group, R and R.sup.1 are independently selected from H and substituent groups; Y and Z are independently selected from H and alkyl, aryl or heteroaryl groups; provided that Y and Z taken together with the nitrogen atom may form a 5-10 membered heterocyclic ring group which may contain one or more further heteroatoms selected from N, O and S.

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Edinburgh, United Kingdom

Hamish McNab