Patent GB-712651-A (GB)
Title: Improvements in merocyanine dyestuffs
IPC: C09B23/10
Filed: 1952-02-19
Abstract: Dyes of the general formula <FORM:0712651/IV(c)/1> wherein n is 0 or 1, m is 1 or 2, R1, R2, R3 and R4 are hydrogen atoms, R5 is a hydrocarbon radical, and X is the residue of a 5- or 6-membered heterocyclic nitrogen ring or a polycyclic homologue thereof and wherein the benzene nucleus A may carry one or more substituents or a fused-on ring, are prepared by heating a thio oxindole, the benzene nucleus of which may carry one or more substituents or a fused-on ring, with the product obtained by reacting together a dianil of malondialdehyde or glutacondialdehyde, which may carry one or more hydrocarbon substituents, and a quaternary salt of a heterocyclic nitrogen compound, carrying a methyl or ethyl group in the a-or g -position to the quaternary nitrogen atom or with a heterocyclic compound carrying a methylene group in the a-position to a tertiary nitrogen atom, wherein the quaternary or tertiary nitrogen atom forms part of a 5- or 6-membered ring.  In modifications, (a) the quaternary salt of the heterocyclic nitrogen compound is heated with the reaction product of the thio-oxindole and the dianil of melondialdehyde or glutacon dialdehyde, and (6) the thio-oxindole, the dianil (preferably in the form of a dihydrochloride), and the quaternary salt or the heterocyclic compound are heated together. Thio-oxindole or 6-ethoxy-thio-oxindole may be used, and the quaternary salt may be quinaldine or lepidine methiodide or ethiodide; a- or g -picoline, 5 : 6-benzoquinaldine, 2-methylbenzselenazole, 1\sv-phenyl-1-methylindolo-(3\sv : 2\sv-3 : 4)-isoquinoline, or 2 : 3 : 3-trimethylindolenine methiodide; or 2-methylbenzthiazole, 2 : 5 : 6-trimethylbenzthiazole, 2-methyltetrahydro-6 : 7-benzbenzthiazole, 2-methyl-4 : 5-diphenylthiazole, 6-chloro-2-methylbenzthiazole, or 2-methyl - 4 : 5 - benzbenzthiazole ethiodide.  The heterocyclic base may be 1 : 3 : 3-trimethyl-2-methyleneindoline.  The reactants may be heated together in methanol or pyridine, and a base such as potassium hydroxide, sodium methoxide, piperidine, or triethylamine may be added.  In example 1, a warm ethanol solution of thio-oxindole is added to an ethanol solution of melondialdehyde dianil, and the mixture refluxed.  The product is dissolved with 2-methylbenzthiazole ethiodide in pyridine, triethylamine is added, and the mixture refluxed.  In example 2, an ethanol solution of sodium ethoxide is added to a solution of thio-oxindole, 2-methylbenzthiazole ethiodide, and glutacondialdehyde diaril hydrochloride in boiling ethanol, and the mixture cooled to 0 DEG C.  In example 3, an ethanol solution of sodium ethoxide is added to an ethanol solution of thio-oxindole and the reaction product of glutacondialdehyde dianil and 2-methylbenzthiazole ethiodide, and the mixture stirred for 48 hours. In example 4, thio-oxidole and the reaction product of melondialdehyde dianil and 2-methylbenzthiazole ethiodide are added to dry pyridine, and the mixture boiled.  In example 5, 2-(6-acetanilido-1 : 3 : 5-hexatrienyl)-quinoline methiodide and 6-ethoxy-thio-oxindole are dissolved in boiling ethanol, triethylamine is added, and the mixture boiled.  According to the Provisional Specification, the merocyanine dyes may be prepared by heating with a quaternary salt of a heterocyclic nitrogen compound carrying a methyl or ethyl group in the a or g -position to the quaternary nitrogen atom or with a heterocyclic nitrogen compound carrying a methylene group in the aposition to a tertiary nitrogen atom with an intermediate of the general formula: <FORM:0712651/IV(c)/2> wherein Y is a -CH=NAryl, -CH(O Alkyl)2, -CO-R, or -CS-R group, where R is a hydrocarbon radical.