GB637815A - Improvements in and relating to a process for preparing polymethine dyestuff-intermediate products and polymethine dyestuffs - Google Patents

Abstract

<FORM:0637815/IV (b)/1> <FORM:0637815/IV (b)/2> Compounds of the general formula II, wherein Y represents the non-metallic atoms to complete a 5- or 6-membered heterocyclic nucleus, which may have a fused-on arylene nucleus, R1 is a substituted or unsubstituted alkyl, aryl, or alkylene group, L is a substituted or unsubstituted methine group, R2 is a substituted or unsubstituted alkyl group, X is an acid radical, and m is 1 or 2, are prepared by reacting a compound of the general formula I with a quaternizing agent of the formula R2X. Specific examples are given of the reaction of 2 - formylmethylene - N - methyl - 2 : 3 - dihydrobenzthiazole, 2 - formylmethylene - N - ethyl - 2 : 3 - dihydrobenzselenazole, 2 - formylmethylene - N - ethyl - 2 : 3 - dihydro - a - naphthathiazole, and 2-formylmethylene-N-ethyl-2 : 3-dihydrobenzthiazole with dimethyl sulphate and of 2-formylmethylene-N-ethyl-2 : 3-dihydrobenzthiazole with methyl iodide.ALSO:<FORM:0637815/IV (c)/1> Carbocyanine dyes are prepared by reacting a compound of the general formula Fig. II, wherein Y represents the non-metallic atoms to complete a 5- or 6-membered heterocyclic nucleus, which may have a fused-on arylene nucleus, R1 is a substituted or unsubstituted alkyl, aryl or alkylene group, L is a substituted or unsubstituted methine group, R2 is a substituted or unsubstituted alkyl group, X is an acid radical, and m is 1 or 2, with a heterocyclic compound containing a reactive methyl or methylene group. 3 : 31-Diethyloxathiacarbocyanine iodide is prepared by heating together 2-(b -methoxyvinyl)-benzthiazole ethyl methylsulphate and 2-methylbenzoxazole diethyl sulphate in acetic anhydride containing triethylamine and adding aqueous potassium iodide. 3 : 31-Diethyloxaselenacarbocyanine methylsulphate and 11 : 3-diethylthia-41-carbocyanine iodide are similarly prepared.