Eastman-kodak Company

Ewell R Cook

William N Washburn

Stephen P Singer

Jared B Mooberry

John M Buchanan

Glen M Dappen

Gary S Proehl

A novel blocked photographically useful compound comprises a new blocking group that (a) comprises two electrophilic groups, the least electrophilic of which is bonded directly or through a timing group to the photographically useful group (PUG) of the compound, (b) is capable of reacting with a dinucleophile reagent, and (c) has the two electrophilic groups separated from each other by a bond or unsubstituted or substituted atom that enables nucleophilic displacement to occur with release of PUG when the compound is reacted with a dinucleophile reagent. Such a blocked photographically useful compound is useful in a photographic material and process to provide increased stability and enable more rapid release of the photographically useful group upon reaction with a dinucleophile reagent.

Photographic element and process comprising a blocked photographically

Particular heterocyclic compounds are useful as color-forming couplers in analytical compositions, elements and methods. These compounds are represented by the structure: ##STR1## wherein R is a solubilizing group, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently hydrogen, alkyl, alkoxy, aryl, aryloxy, a heterocyclic group, halo, amino or R, and Z represents the carbon atoms necessary to complete the nucleus of a 5- or 6-membered fused ring. The color-forming coupler is combined with an oxidizable color developing compound, e.g. 4-aminoantipyrine to provide a chromogenic composition. This composition can be used in solution or dry assays of biological fluids to produce a color dye in the presence of hydrogen peroxide or other analytes, e.g. glucose or uric acid, which react to produce hydrogen peroxide.

Color-forming couplers and their use in the analytical determination of

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Rochester, NY, United States of America

Ewell R Cook