GB584482A - Improvements in or relating to photographic light-sensitive elements - Google Patents

Abstract

Dyes of the formula <FORM:0584482/IV/1> wherein R1 is H or an alkyl or aralkyl group, R2 is an alkyl, aralkyl, or aryl group, D is the residue of a 5- or 6-membered heterocyclic nucleus, X is an acid residue, and n is 0 or 1 are prepared by reacting a quaternary salt of a 5- or 6-membered heterocyclic nitrogen compound containing a reactive methylene group in the a - or g -position to the quaternary nitrogen atom with furfural or furfural acrolein. The heterocyclic nitrogen base may be used and the product converted to the quaternary salt by reaction with an acid or an alkyl or aralkyl salt. The acid may be a colloid containing acid groups, e.g. silvestic acid, abietic acid, polymethyl methacrylate containing free carboxyl groups, polyvinyl phthalate, or the alkali-soluble fraction of yellow gum accroides. The free dye base may also be reacted with an acid derived from an anion-active compound. The residue D may be the residue of a thiazole, oxazole, or selenazole, or the corresponding polycyclic compounds such as benzthiazole or naphthathiazole, or may be pyridine, quinoline, or indolenine. In example 1, a dye is prepared by refluxing together 2 : 3 : 3-trimethylindolenine methiodide, furfural, anhydrous zinc chloride and ethyl alcohol. In example 2, a dye is prepared by refluxing together 2 : 3 : 3-trimethylindolenine methiodide, furfuryl acrolein, zinc chloride, and ethyl alcohol. In example 3, a dye is similarly prepared using the quaternary salt from 1-methylbenzthiazole and furfural, and pouring the reaction product into saturated aqueous ammonium chloride. In example 4, a dye base is prepared using quinaldine, furfural and anhydrous zinc chloride, the reaction product is treated with hydrochloric acid to obtain the hydrochloride and a base is added to precipitate the dye base. The base may be dissolved in a methyl alcohol-acetone solution of alkali-soluble partially hydrolysed methyl methacrylate. Specifications 540,382, 548,411, [both in Group XX], and 575,512 are referred to.