Patent GB-461668-A (GB)
Title: Improvements in or relating to dyestuffs
IPC: C09B55/00
Filed: 1935-08-16
Abstract: Compounds containing two heterocyclic nitrogen nuclei linked by a single nitrogen atom or by a chain of atoms including two nitrogen atoms, are prepared by condensing a quaternary salt of a heterocyclic nitrogen compound containing a reactive thioether or selenoether group with ammonia or an amidine having at least three replaceable hydrogen atoms attached to the nitrogen atoms or one of their salts. Starting materials comprise on the one hand quaternary salts derived from thioether, selenoether, thione or selenone derivatives of thiazolines, oxazoles, oxazolines, selenazoles, selenazolines, pyridines, quinolines, indolenines, pyrimidines, thiodiazoles, quinazolines, benz-, naphtha- and anthrathiazoles; and on the other hand ammonia and amidines of the general formula NH2--CZ=NH wherein Z stands for hydrogen, an alkyl, aryl or aralkyl group or an oxy, alkoxy, thiol, thioether, amino or substituted amino group, specific mention being made of formamidine, acetamidine, benzamidine, guanidine, urea, thiourea, O-alkyl pseudo ureas, S-alkyl pseudo-thio-ureas.  In examples: (a) 1-methylthiolbenzthiazole methyl-p-toluenesulphonate is condensed with thiourea methyl sulphate, acetamidine hydrochloride, formamidine hydrochloride, propionamidine hydrochloride, benzamidine hydrochloride, ammonium nitrate and guanidine carbonate, the reaction being carried out in pyridine and the dye in each case being precipitated as the iodide by pouring into potassium iodide; (b) 1-ethylmercaptobenzthiazole ethyl-p-toluenesulphonate is condensed with acetamidine hydrochloride in pyridine and the dye precipitated as the iodide by means of potassium iodide; (c) 2-ethylthiolquinoline methyl-p-toluenesulphonate is condensed with acetamidine hydrochloride and the dye precipitated as the perchlorate, or with ammonia in presence of sodium alcoholate followed by precipitation as the perchlorate; (d) 1-methylthiobenzoxazole methyl-p-toluenesulphonate is condensed with acetamidine hydrochloride, or propionamidine hydrochloride, in pyridine and the dye precipitated as the iodide in each case; (e) 1-methylthio-5.6-benzobenzthiazole methyl-p-toluenesulphonate is condensed with acetamidine hydrochloride, propionamidine hydrochloride or benzamidine hydrochloride in pyridine and the dye precipitated as the iodide in each case; (f) 1-methylthio-3.4-benzobenzthiazole methyl-p-toluenesulphonate is condensed with acetamidine hydrochloride or propionamidine hydrochloride or benzamidine hydrochloride in pyridine and the dyes precipitated either as the iodide or bromide; (g) 1-methylthio-4.5-methylenedioxybenzthiazole-methyl-p -toluenesulphonate is condensed with acetamidine hydrochloride; (h) 1-methylthio-4.5 - dimethoxybenzthiazole methyl-p-toluene-sulphonate is condensed in pyridine with acetamidine hydrochloride or propionamidine hydrochloride in the latter ease the dye being precipitated as the iodide; (i) 4-methylthioquinazoline methyl-p-toluenesulphonate is condensed with acetamidine hydrochloride in pyridine and the dye precipitated as the iodide; (j) dimethylthio-a .b - and b .b <1>-diazole are respectively condensed with methyl-p-toluene-sulphonate and the products with ammonium nitrate in pyridine, the dyes being precipitated as the iodides. Many of the products are sensitizers for photographic silver halide emulsions (cf. Specification 447,109).