Patent GB-738197-A (GB)
Title: Polymethine dyes and process of preparing them
IPC: C09B23/01
Filed: 1953-03-30
Abstract: Mesocarbocyanine dyes of the general formula I <FORM:0738197/IV (c)/1> wherein R represents an alkyl or hydroxyalkyl group, R1 and R2 represent substituted or unsubstituted aryl groups, X is O or S, L represents a substituted or unsubstituted methine group and Q completes a 5-membered heterocyclic nucleus of 3 carbon atoms, one nitrogen atom and the remaining atom being O or S, are made by condensing a compound of the formula II <FORM:0738197/IV (c)/2> where R4 is a substituted or unsubstituted aryl group, R3 is acyl and X1 is an anion, with a compound of the formula III <FORM:0738197/IV (c)/3> or by condensing a compound of the formula IV <FORM:0738197/IV (c)/4> with a compound of formula VIII <FORM:0738197/IV (c)/5> wherein R5 represents an alkyl group and R6 represents hydrogen or an alkyl group.  Both the above condensations are assisted by heat and a basic condensing agent such as triethylamine, and a solvent such as acetone, pyridine or an alcohol may also be used.  R may be methyl, ethyl or b -hydroxyethyl, R1 and R2 may be phenyl, p-t.-octyl phenyl, o-, m-or p-chlorophenyl, o-, m- or p-tolyl, o-, m-, or p-methoxyphenyl, 3 : 4-dimethoxyphenyl, p-ethoxyphenyl, o-, m-, or p-bromophenyl, o-, m-or p-hydroxyphenyl, p-diphenyl, or a - or b -naphthyl, and X1 may be halide, benzene sulphonate, p-toluene sulphonate, methyl sulphate, ethyl sulphate, perchlorate or thiocyanate.  When the nucleus <FORM:0738197/IV (c)/6> of the dyes of formula I has the value <FORM:0738197/IV (c)/7> or <FORM:0738197/IV (c)/8> where R7 is alkyl or carbalkoxyalkyl and R8 is alkyl, they may be quaternerized with a salt R10X4 wherein R10 is alkyl and X4 is an anion to give dyes of the formul  XV <FORM:0738197/IV (c)/9> or XVI <FORM:0738197/IV (c)/100> and either of these dyes may be condensed with a ketomethylene compound of formula III or with a cyclammonium quaternary salt of the formula XVII <FORM:0738197/IV (c)/111> wherein R9 is an alkyl group, X3 is an anion, n is 0 or 1 and Z completes a heterocyclic nucleus, to give trinuclear complex mercarbocyanine dyes.  Such condensations may be carried out under conditions similar to those given above for the first condensations.  Numerous examples are given of the preparation of dyes of formula I, XV and XVI and of the complex trinuclear dyes derived from those of formul  XV and XVI. The intermediates of formula II are prepared by acylating the corresponding compounds wherein R3 is H, which latter are prepared according to the method described in Specification 585,707 by reacting the a -methyl quaternary salts with R4-N=CHOR5, wherein R4 and R5 are as defined above.  Examples of the preparation of the intermediates are given.  Specification 738,258 also is referred to.ALSO:Thiazoles of the general formula <FORM:0738197/IV (b)/1> wherein R represents an alkyl or hydroxyalkyl group, R1, R2 and R4 represent substituted or unsubstituted aryl groups, R3 represents an acyl group, X is oxygen or sulphur and X1 is an acid radical, are prepared by acylating the corresponding compounds wherein R3 is H, which compounds are prepared according to the method described in Specification 585,707 by reacting a quaternary salt of the formula <FORM:0738197/IV (b)/2> with a compound of the formula R4-N=CH-OR5 wherein R5 is an alkyl group.  The compounds of formula IV are obtained by quaternization of the corresponding bases, which are themselves obtained by condensing a halogenated compound of formula <FORM:0738197/IV (b)/3> wherein X2 represents a halogen atom, with thioacetamide. The compounds of formula VI are prepared by halogenating a ketone of the formula <FORM:0738197/IV (b)/4> The halogenation may be carried out, e.g. with bromine, in a solvent such as CS2, CHCl3 or CCl4.  The o -aryloxyacetophenones and o -arylthioacetophenones of formula VII can be prepared by the conventional Williamson ether synthesis.  Examples are given of the synthesis of compounds of formula VII wherein R1 is phenyl, b -naphthyl, p-methoxy-phenyl, p-chloro-phenyl, p-bromo-phenyl and 3 : 4-dimethoxy-phenyl, and R2 is phenyl, p-ethoxy-phenyl, p-chloro-phenyl, p-bromo-phenyl, p-t.-octyl-phenyl and p-diphenyl. Examples are given of the halogenation of certain of these compounds to give compounds of formula VI and the condensation of these with thioacetamide to give the bases corresponding to formula IV.  Other values of R1 and R2 are specified. Specification 738,258 also is referred to.