GB563137A - Improvements in or relating to carbocyanine bases - Google Patents

Abstract

Carbocyanine bases are produced by condensing a compound of the formula <FORM:0563137/IV/1> (wherein D2 is the residue of a 5- or 6-membered heterocyclic nitrogen nucleus, R is H or alkyl, aryl, or aralkyl, R1 is alkyl or aralkyl, R2 is alkyl, aryl, or aralkyl, X is an anion, and n is 0 or 1), which may be prepared as described in Specification 555,935, with a 5- or 6-membered heterocyclic nitrogen compound containing a methyl or mono-substituted methyl group in the a or g -position to the heterocyclic nitrogen atom, and then treating the product with a base stronger than the carbocyanine base being prepared, e.g. ammonia or, if the base is present during the condensation, a tertiary organic base. The heterocyclic nitrogen nuclei in the two components may be the same or different and may be selected from thiazoles, oxazoles, selenazoles and their polycyclic homologues of the benzene, naphthalene, acenaphthene, and anthracene series, pyridine and its polycyclic homologues, e.g. quinoline and a - and b -naphthaquinolines, lepidines, indolenines, diazines, e.g. pyrimidines and quinazolines, diazoles, e.g. thio-b .b 1-diazole, oxazolines, thiazolines and selenazolines. The benzene rings in the polycyclic compounds may be substituted with one or more groups, e.g. alkyl, aryl, NH2, OH, alkoxy, or methylenedioxy groups or by halogen atoms. The groups R, R1 and R2 and the substituent R3 (if any) in the a - or g -methyl group in the second component may be methyl, ethyl, propyl, butyl, benzyl, or naphthyl, and R, R2 and R3 may be phenyl or naphthyl groups which may be substituted by alkyl, aryl, NH2, OH, or alkoxy groups or by halogen atoms. The condensation may be effected by heating the reactants together either along or in a solvent, e.g. pyridine. 1-o -(21 - Quinolylpropenylidene)-N-ethyldihydrobenzthiazole is prepared by fusing together 1-o -ethylthiovinylbenzthiazole ethyl-p-toluenesulphonate and quinaldine, suspending the solid product in ethyl alcohol, and passing ammonia through the cooled suspension and adding water. 1-o -(21-Quinolylpropenylidene)-N - methyldihydrobenzthiazole, 2 - o - (21 - p - toluquinolylpropenylidene) - N - methyldihydro - 3 : 31 - dimethylindole, 2 - o - (21 - quinolylpro - penylidene) - N - ethyldihydroquinoline, 1-o -(11-benzthiazolylpropenylidene) - N - methyldihydro - benzthiazole, and 2-o -(41-quinolylpropenylidene)-N - methyldihydro - 3 : 31 - dimethylindole are similarly prepared. The carbocyanine bases are photographic sensitizers. Samples have been furnished under Section 2 (5) of 1-o -(21-quinolylpropenylidene) - N - methyldihydrobenz - thiazole prepared (a) by fusing together 1-o -ethylthiovinylbenzthiazole methyl - p - toluenesulphonate and quinaldine and adding diethylamine to a cooled suspension of the product in ethylalcohol and (b) by boiling together 1-o -ethylthiovinylbenzthiazole methyl - p - toluenesulphonate, quinaldine, toluene, and triethylamine.