GB822066A - Photographic filter and antihalation layers - Google Patents

Abstract

Methine dyes of the general formulae <FORM:0822066/IV(c)/1> and <FORM:0822066/IV(c)/2> wherein R is a benzene ring with a p-substituted amino substituent or a heterocyclic ring containing at least one nitrogen atom, R1 is H, alkyl or substituted alkyl, R2 is alkyl, aryl, carboxyl or substituted carboxyl, R, R1 or R2 containing a carboxyl group which forms an internal salt with the N(+) atom, R3 is H or alkyl, and the carbocyclic rings of the indole nuclei may carry alkyl or halogen substituents or have fused on benzene rings, are prepared by reacting an indole or naphthindole compound with the appropriate benzaldehyde or heterocyclic aldehyde. Suitable indole derivatives are 2-methyl indole and its N-propionitrile and Npropionic acid derivatives, 2-phenylindole-Npropionic acid and its nitrile and ethyl ester, indole-2-carboxylic acid and its methyl ester, 1:2 - dimethyl indole, 2 - methyl - a - naphthindole - N - propionic acid, 1:2 - dimethyla - or b -naphthindole, 2-phenylindole, 1-ethyl2 - methyl - a - or b - naphthindole, 5 - chloro2 - methyl - indole, 5 - chloro - 1:2 - dimethyl indole, 2:5 - dimethyl indole and 1 - methyl indole-2-carboxylic acid. Suitable aldehydes are p - (N - methyl - N - carboxymethyl - amino) benzaldehyde, p - (dicarboxymethyl - amino) benzaldehyde, 6 - formyl - tetrahydroquinolineN-acetic acid, 2-hydroxy-indole-3-aldehyde, a pyrrole - aldehyde, indole - b - aldehyde, indole3 - aldehyde - 2 - carboxylic acid, carbazole3 - aldehyde - N - propionic acid, p - (dihydroxyethylamino)benazldehyde, p - p1 - diformyl - N ethyl - diphenylamine, p - dimethylamino benzaldehyde, 3 - methyl - 4 - (N - methyl - N carboxymethyl - amino)benzaldehyde, 3 methyl - 4 - (N - dicarboxymethyl - amino) benzaldehyde, p - (N - methyl - N - carbethoxymethylamino)benzaldehyde and p,p1-diformyldiphenylamine. The condensations may be carried out in glacial acetic acid in the presence of phosphorus oxychloride. Specifications 397,740 and 399,713, [both in Group IV], are referred to.ALSO:p,p1 - Diformyl - N - ethyl diphenylamine is prepared by mixing dimethyl formamide and phosphorus oxychloride while cooling, and then adding N-ethyl diphenylamine dropwise. The mixture is then heated and introduced into dilute hydrochloric acid. Specifications 397,740 and 399,713, [both in Group IV], are referred to.