Patent GB-795134-A (GB)
Title: Improvements in or relating to methine dyes
Inventor: FRY DOUGLAS JAMES
IPC: C09B23/10
Filed: 1955-08-31
Abstract: 2 - Methylthio - 1 - azacycloheptene methiodide is prepared by treating thio-e -caprolactam with methyl iodide to give 2-methylthio-1-azacycloheptene hydriodide, treating this with KOH and K2CO3 to give the free base and then quaternizing the latter with methyl iodide.  If ethyl iodide is used instead of methyl iodide, 2 - ethylthio - 1 - azacycloheptene ethiodide is obtained.  If thio-e -enantholactam is used instead of the thio-e -caprolactam, 2-methylthio-7-methyl-1-azacyclohepten methiodide is obtained.  2 - Methylthio - 1 - azacyclo - octene methiodide and 2 - ethylthio - 1 - azacyclo - octene ethiodide are similarly obtained from 2-thio-heptamethylenimine using methyl iodide or ethyl iodide respectively.  Thio - e  - caprolactam is obtained by treating e -caprolactam with P2S5.  Thio-e -enantholactam is similarly prepared.ALSO:Dyes having one of the following general formul : <FORM:0795134/IV (b)/1> <FORM:0795134/IV (b)/2> wherein R1 is an alkyl or aralkyl group, x is 4, 5 or 6, Z and Y are cyano, or carboxylic acid, ester or acyl groups, R3 is hydrogen or an alkyl, aralkyl or aryl group, R4 is hydrogen or an alkyl or alkoxy group and D1 completes a 5- or 6-membered heterocyclic nucleus, and the corresponding dyes wherein one or more of the (CH2)x groups has an alkyl substituent, are prepared by condensing a quaternary salt of the formula: <FORM:0795134/IV (b)/3> (wherein R2 is an alkyl or aralkyl group and X is an anion) with the appropriate compound containing a reactive methyl group. Reactive methyl compounds specified are 4-isopropylidene - 3 - methyl - 1 - phenyl - 5 - pyrazolone, ethyl isopropylidene cyanoacetate, 3-ethyl-5-isopropylidene - 2 - thiothiazolid - 4 - one and 3 - ethyl - 5 - (11 - alkoxyethylidene) - 2 - thiothiazolid-4-one.  Examples are given of dyes wherein x is 4, 5 or 6 and R1 is methyl or ethyl. According to the first Provisional Specification, the quaternary salts of formula I wherein x is 5 may be reacted with open chain compounds of the formula XCH2Y, cyclic compounds of the formula: <FORM:0795134/IV (b)/4> and quaternary salts of 5- or 6-membered heterocyclic nitrogen compounds having in a -or g -position to the nitrogen a CH3 or CH3 -CR4 = CH- group, wherein the various symbols are as defined above, except that R4 may also be aralkyl, aryl, aralkoxy, alkylthio, aralkylthio or arylthio.  Additional compounds specified for reacting with salts of formula I are malonitrile, ethyl cyanoacetate, ethyl acetoacetate, 3 - methyl - 1 - phenyl - 5 - pyrazolone, 3 - ethyl - 2 - thiothiazolid - 4 - one, 1,3 - diethyl-2 - thiobarbituric acid and quaternary salts of quinaldine, lepidine, 2-methylbenzthiazole, 4-methyl quinazoline, 2 - (21:21 - dimethylvinyl)-benzthiazole, 2 - (21 - alkoxyprop - 21 - enyl) 1:3:3 - trimethyl indolenine and 2 - (21-ethylthio - prop - 21 - enyl) benzthiazole.  According to Provisional Specification 8303/56, all the above reactions may be carried out using compounds of formula I but wherein x is 4 or 6.  Examples of these condensations are given in both Provisional Specifications.