Patent GB-562567-A (GB)
Title: Improvements in or relating to polymethine dyestuffs
IPC: C09B23/08
Filed: 1943-01-01
Abstract: Polymethine dyes are prepared by condensing together as first reagent a compound of the general formula <FORM:0562567/IV/1> wherein R1 is an alkyl group (e.g. methyl or ethyl, R2 is H or an alkyl or aralkyl group, R3 is an alkyl (including substituted alkyl (e.g. hydroxylaklyl), aralkyl, or unsaturated aliphatic group (e.g. allyl), A is an acid radical, D1 is the residue of a 5- or 6-membered heterocyclic nucleus, and n is 0 or 1, and as second reagent a compound of one of the following classes:-(a) quaternary salts of 5- or 6-membered heterocyclic nitrogen compounds containing a reactive methylene (including methyl or mono-substituted methyl) group or an amino group in the a - or g -position to the quaternary N atom; (b) five-membered ring compounds of general formula <FORM:0562567/IV/2> wherein D2 is the residue of a heterocyclic N keto-methylene ring and R4 is H or an alkyl, aryl, or aralkyl group; (c) carbocyclic compounds containing a keto-methylene group; (d) compounds of type (b) which contain a substituent <FORM:0562567/IV/3> in place of the two H of the methylene group, R5 being H or an alkyl, aryl, or aralkyl group; and (e) hydrazines and substituted hydrazines.  If D1 is the residue of a polycyclic heterocyclic nitrogen compound, the benzene nuclei thereof may contain substituents, e.g. alkyl, aryl, amino, hydroxy, or alkoxy groups, or halogen atoms.  Compounds of type (a) are of the customary classes.  Compounds of type (b) include rhodanic acid, oxarhodanic acid and the N-alkyl, N-aryl, and N - aralkyl derivatives thereof, oxindoles, pyrazole - 5 - ones, hydantoin, thiohydantoin, q -hydantoin, and q -thiohydantoin. Compounds of type (c) include 1 : 3-indane-dione, and the hydrindones.  When employing compounds of type (b) such as rhodanic acid the resulting product contains a thio group and can be further reacted as described in Specification 489,335.  The condensation may be effected by heating the reagents together in the presence of a base, e.g. pyridine or triethylamine, or in an alcoholic solution of sodium acetate.  2 - Methyl - 11 - b  - hydroxyethyl - thia - (41) - quinodicarbocyanine iodide is prepared by refluxing together 1-(o -ethylthiobutadienyl)-benzthiazole methiodide, lepidine b -hydroxyethiodide, ethyl alcohol, and triethylamine.  2 : 21 - Dimethylthiazoxadicarbocyanine iodide, 2 - methyl - 11 - ethylthia - (21) - quinodicarbocyanine iodide, 2 - methyl - 11 : 31 : 31 - trimethylthiaindodicarbocyanine iodide, 2 - ethyl - 11 - methyloxa - (21) - quinodicarbocyanine iodide, 3 - methyl - 2 - thio - 4 - keto - 5 - o  - (N - ethyldehydrobenzoxazolylidene) - butenylidene - rhodanine, 2 - ethyl - 11 : 31 : 31 - trimethyloxaindodicarbocyanine perchlorate, 2 - methyl - 21 - b  - hydroxyethylthiadicarbocyanine iodide, 2-methyl-21-ethylthiaselenadicarbocyanine iodide, 2 - ethyl - 11 : 31 : 31 - trimethylselenaindodicarbocyanine perchlorate, 3 - methyl - 11 - 31 : 31 - trimethylthiazolineindodicarbocyanine perchlorate, 2 : 21-dimethyl - 7 - az - thiadicarbocyanine iodide, (1 - methyl - dihydroquinonelylidene - 2) - butenylidene - 1 1 : 31 - diketohydrindene, 2 - methyl - 11 - ethyl - 51 : 61 - benzthia - (4) - quinodicarbocyanine iodide, 7 - (1 - methyl - 1 : 2 - dihydroquinolylidene - 2) - 2 - (1 - phenyl - 3 - methyl - 5 - keto - 4 : 5 - dihydropyrazolylidene - 4) - 3 : 5 - heptadiene, 2 - b  - acetoxyethyl - 21 - b  - hydroxyethylthiadicarbocyanine iodide, and d - (1 - methyldihydrobenzthiazolylidene) - crotonaldazine are similarly prepared.  Photographic sensitizing data are given. Specifications 425,609, 513,596, 546,565, and 562,566 also are referred to.