Patent GB-615205-A (GB)
Title: Improvements in and relating to the manufacture of dyes and photographic emulsions sensitised therewith
IPC: C09B23/02
Filed: 1939-12-28
Abstract: Dyestuffs suitable for sensitising photographic emulsions are prepared from intermediates obtainable according to the process of Specification 587,434, and having two heterocyclic nitrogen containing nuclei, the nitrogen atoms of which are linked by a conjugated chain of 3 or 5 carbon atoms, and wherein at least one of the heterocyclic nuclei has the formula <FORM:0615205/IV (c)/1> or <FORM:0615205/IV (c)/2> where n=1 or 2.  The intermediate is treated with (a) condensing agents known to be used in the formation of methine dyestuffs, e.g. acetic anhydride; (b) compounds which supply the central carbon atom of methine dyestuffs; (c) intermediates known to be used with cyclammonium salts for the formation of methine dyestuffs, or (d) aromatic aldehydes.  Orthocarboxylic esters, imino ethers, alkylesters of arylated thioimido acids (c.f. Specification 412,309) and esters or salts of nitrous acid are specified compounds for supplying the central carbon atom.  The following intermediates which may be used are specified: halogeno, alkylmercapto, arylmercapto, aralkylmercapto, alkylseleno, arylseleno and aralkylseleno derivatives; alkylmercapto-, aralkylmercapto-, alkylseleno-, aralkylseleno-, anilino-, acetanilino- and acetamino-vinylene; anilino-, acetanilino-, formyl-, thioformyl-, acyl- and thioacyl - methylene; (beta - alkylmercapto - beta alkyl) vinyl, (beta-substituted alkylmercapto-beta-alkyl) vinyl, (beta-aralmercapto-beta alkyl) vinyl, (beta-dialkylmercapto) vinyl, (beta-alkylseleno-beta alkyl) vinyl and (beta-substituted alkylseleno-beta alkyl) vinyl derivatives of nitrogenous heterocyclic compounds and their salts. The mercapto derivatives described in Specification 424,559 having the formula <FORM:0615205/IV (c)/3> wherein R and R1 are alkyl and the beta alkylmercaptovinyl derivatives described in Specification 538,857, having the formula <FORM:0615205/IV (c)/4> wherein R=alkyl or aralkyl, R1=alkyl or phenyl, R11=aralkyl, are mentioned.  In examples (1) N-ethyl-2-thioquinolonedimethylsulphate is condensed with 1:2-trimethylene-3:4-benzobenzthiazole or 1:2-tetramethylenebenzthiazole bromide in the presence of triethylamine; (2) ethyl orthoformate is reacted with 1:2-tetramethylene benzthiazole bromide, or 1:2 - tetramethylene - 3 : 4 - benzobenzthiazole bromide to give carbocyanines; (3) 1:2-tetramethylene benzthiazolebromide is condensed with 2 - acetanilidovinyl - 4 - dimethylaminobenzthiazole; (4) 1:2-tetramethylene-3:4-benzobenzthiazole bromide is condensed with 2-acetanilidovinylbenzthiazolethiodide; (5) 1:2 - trimethylene - 3:4 - benzobenzthiazole bromide is condensed with the dimethylsulphate of [N-ethyl-5:6-benzobenzthiazolidenemethyl] methylthioketone. Specification 592,483 also is referred to.  Samples have been furnished under Sect. 2 (5) of dyestuffs obtained by condensing trimethylene-5-methylthiodiazolbromide with benzoylmethylene - N - ethyl - 5 - methyl - 1:2-dihydrothiodiazole and the dimethylsulphate of thioacetylmethylene - N - ethyl - 1 : 2-dihydrobenzthiazol with trimethylenebenzselenazolbromide and converting the former into the perchlorate and the latter into the iodide.