Patent GB-633735-A (GB)
Title: Improvements in or relating to the production of methine dyestuffs and to photographic emulsions sensitised therewith
IPC: C09B23/10
Filed: 1947-06-11
Abstract: Methine dyes are prepared by reacting a compound of the general formula <FORM:0633735/IV (c)/1> wherein R is alkyl, R1 is aryl, and R2 is H or alkyl, with a heterocyclic nitrogen compound containing a reactive methylene group, e.g. a compound of the general formula (A) <FORM:0633735/IV (c)/2> wherein D1 is the residue of a 5- or 6-membered heterocyclic N nucleus, R3 is alkyl, aralkyl, hydroxyalkyl, or hydroxyaralkyl, R4 is H or a hydrocarbon group, n is 0 or 1, and Y is an acid radical, or a compound of the general formula (B) <FORM:0633735/IV (c)/3> wherein Q is O or S and R5 is H or a hydrocarbon group. The compound of the general formula (A) may be derived from a thiazole, oxazole, selenazole, or a polycyclic homologue thereof (e.g. of the benzene, naphthalene, acenaphthene, or anthracene series), pyridine, quinoline, a  or b -naphthoquinoline, lepidine, indolenine, a diazine (e.g. a pyrimidine or quinazoline), a diazole (e.g. thio-b  : b 1-diazole), a thiazoline, oxazoline, or selenazoline, in which carbocyclic rings, if present, may be substituted with one or more alkyl, aryl, amino, hydroxy, alkoxy, or methylenedioxy groups or halogen atoms.  The reagents may be heated together in presence of a solvent and a base.  3 - Ethyldihydrobenzthiazolylidene - 2 - (41-ethylidene - 21 - phenyl - 51 - oxazolone) is prepared by refluxing together 2-methylbenzthiazole etho-p-toluenesulphonate, 4-ethoxymethylene - 2 - phenyl - 5 - oxazolone, and pyridine.  3 - Ethyldihydrobenzthiazolylidene-2 - (41 - isopropylidene - 21 - phenyl - 51 - oxazolone), 3 - ethyldihydrobenzthiazolylidene - 2-(41 - isobutylidene - 21 - phenyl - 51 - oxazolone), 1 : 3 : 3 - trimethylindolylidene - 2 - (41 - ethylidene - 21 - phenyl - 51 - oxazolone), 1 - ethyl1 : 2 - dihydroquinolylidene - 2 - (41 - ethylidene-21 - phenyl - 51 - oxazolone), 1 - ethyl - 1 : 2 - dihydroquinolylidene - 2 - (41 - isopropylidene - 21-phenyl - 51 - oxazolone), 1 - ethyl - 1 : 4 - dihydroquinolylidene - 4 - (41 - ethylidene - 21-phenyl - 51 - oxazolone), 1 - methyl - 1 : 4-dihydroquinolylidene - 4 - (41 - ethylidene - 21-phenyl - 51 - oxazolone), 3 - ethyldihydrobenzselenazolylidene - 2 - (41 - ethylidene - 21 - phenyl-51 - oxazolone), 3 : 4 - dimethyldihydrothiazolylidene - 2 - (41 - ethylidene - 21 - phenyl - 51-oxazolone), 3 - ethyldihydrobenzoxazolylidene - 2-(41 - ethylidene - 21 - phenyl - 51 - oxazolone) 3 - methyltetrahydrothiazolylidene - 2 - (41-ethylidene - 21 - phenyl - 51 - oxazolone), 3-methyltetrahydrothiazolylidene - 2 - (41 - isopropylidene - 21 - phenyl - 51 - oxazolone), 4 - keto2 - thiotetrahydrothiazole - 5 - (41 - methylene21 - phenyl - 51 - oxazolone), 3 - ethyl - 2 : 3-dihydrobenzoxazolylidene - 2 - (41 - propylidene21 - phenyl - 51 - oxazolone), 3 - ethyl - 2 : 3-dihydrobenzoxazolylidene - 2 - (41 - isobutylidene21 - phenyl - 51 - oxazolone), 3 - methyltetrahydrothiazolylidene - 2 - (41 - isobutylidene - 21-phenyl - 51 - oxazolone), 1 - methyl - 1 : 4-dihydroquinolylidene - 4 - (41 - propylidene - 21-phenyl - 51 - oxazolone), and 1 - ethyl - 1 : 2-dihydroquinolylidene - 2 - (41 - isobutylidene - 21-phenyl-51-oxazolone) are similarly prepared. Specifications 549,202, 585,089 and 633,736, [Group IV (b)], are referred to.