Patent GB-694744-A (GB)
Title: Improvements in or relating to dyestuffs and photographic emulsions containing the same
Inventor: KENDALL JOHN DAVID
IPC: G03C1/22
Filed: 1950-12-05
Abstract: Methine dyes of the general formula <FORM:0694744/IV (c)/1> wherein R and R1 each represent an alkyl or an alkyl group, D is the residue of a 5- or 6-membered heterocyclic nitrogen nucleus, n is O or I, X is a nitrile, carboxyl, acyl, or carbalkoxy group, and Y is a nitrile, carbalkoxy, carbonamido, or N-substituted carbonamido group, are prepared by reacting an alkyl or aralkyl quaternary salt R1A (wherein R1 is an alkyl or aralkyl group and A an acid radicle) with an alkyl or aralkyl quaternary salt of an intermediate of the general formula <FORM:0694744/IV (c)/2> and a compound of the general formula X-CH2-Y, e.g. methyl or ethyl cyanacetate, malonate, or acetoacetate, malodinitrile, cyanacetamide, cyanacetanilide, or acetoacetanilide. Compounds in which both X and Y are acyl (e.g. acetylacetone) are not reactive.  The reagents are heated together in the presence of a base and a solvent.  Ethyl 4-(3-methyl-2 : 3-dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - cyano-2-butenoate is prepared by fusing together methyl (3 - methyl - 2 : 3 - dihydrobenz - thiazolylidene-2)-dithioacetate and methyl p-toluenesulphonate, adding ethyl alcohol, ethyl cyanacetate, and triethylamine, and refluxing.  Ethyl 4 - (3 - ethyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenoate, ethyl 4 - (3 - methyl - 2 : 3 - dihydro - 4 : 5 - benzbenzthiazolylidene - 2) 3 - methylthio - 2 - cyano - 2 - butenoate, ethyl 4 - (3 - methyl - 2 : 3 - dihydro - 5 : 6 - dioxymethylenebenzthiozo - lylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenoate, methyl 4 - (3 - methyl - 2 : 3 - dihydro - benzthiazolylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenoate, ethyl 4 - (3 - ethyl - 2 : 3 - dihydro - benzthiazolylidene - 2) - 3 - ethylthio - 2 - cyano - 2 - butenoate, ethyl 4 - (1 - methyl - 1 : 2 : di - hydroquinolylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenoate, (3 - methyl - 2 : 3 - dihydrobenz - thiazolylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenonitrile, (3 - methyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenamide, (3 - methyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - butenanilide, 4 - (3 - methyl - 2 : 3 - dihydrobenz - thiazolylidene - 2) - 3 - methylthio - 2 - aceto - 2 - butenanilide, ethyl 4 -(3 - methyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - carbethoxy - 2 - butenoate, ethyl 4 -(3 - methyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - acetyl - 2 - butenoate, 4 - (1 - methyl - 1 : 2 - dihydroquinolylidene - 2) -3- methylthio - 2 - cyano - 2 - butenamide, 4 - (3 - ethyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - ethylthio - 2 - cyano - 2 - butenonitrile, 4 - (3 - ethyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - ethyl - thio - 2 - cyano - 2 - butenamide, 4 - (1 - methyl - 1 : 2 - dihydroquinolylidene - 2) - 3 - methylthio - 2 - cyano - 2 - butenonitrile and 4 - (3 - methyl - 2 : 3 - dihydrobenzthiazolylidene - 2) - 3 - methylthio - 2 - carbethoxy - 2 - butenanilide are similarly prepared.  Specification 549,204, [Group IV (b)], is referred to.  Reference has been directed by the Comptroller to Specifications 610,569 and 620,800.