Tetrazaindene compounds and their use in photographic silver halide emulsions
Реферат: The invention comprises tetrazaindene derivatives of formula: <FORM:0869882/IV (b)/1> in which X represents a divalent aliphatic organic group containing at least 2 carbon atoms. The group X may be, for example, ethylene, propylene, or tetramethylene and may be substituted, for example, by chlorine, hydroxyl or carboxyl. The alkylene chain may also be interrupted by other atoms such as oxygen or nitrogen. These compounds may be prepared by condensing 2-ethylmercapto-4-hydroxy-6-methyl-pyrimidine, <FORM:0869882/IV (b)/2> with a dihydrazide of formula <FORM:0869882/IV (b)/3> to give a hydrazide compound of formula: <FORM:0869882/IV (b)/4> and refluxing this in a solution containing a strong mineral acid such as hydrochloric or hydrobromic acid, and a solvent such as glacial acetic acid. The 2-ethylmercapto-4-hydroxy-6-methyl-pyrimidine may be prepared by heating thiourea with bromethane and adding acetoacetic ester to the resulting mixture. The dihydrazide used as starting material may be prepared by reacting the butyl ester of the acid X(COOH)2 with hydrazine. Examples are given of the preparation of tetrazaindene derivatives of the above formula in which X is -CHOH-CHOH-; -CH2-O-CH2CH2-O-CH2-; -CH2CH2- and -(CH2)4-. The new compounds may be used in the preparation of photographic silver halide emulsions (see Group XX). Specifications 235,211, 602,158, 602,160, 618,061, 636,140, 658,592, 661,645, 664,230, 680,593, 682,355, 742,219, 742,221 and 742,224 are referred to.
N-alkylhydroxylamine derivatives and their use as antioxidants in photographic color developers and processing methods
Номер патента: WO1996028761A1. Автор: Thomas Henry Jozefiak,Lee Hamilton Latimer,Lynda Woedy Mcgarry,Carl Anthony Marrese,Elizabeth Gertrude Burns. Владелец: EASTMAN KODAK COMPANY. Дата публикации: 1996-09-19.