Patent GB-662775-A (GB)
Title: Improvements in or relating to the preparation of dyestuffs and to the sensitising of photographic emulsions therewith
Inventor: DOYLE FRANK PETER
IPC: C09B23/14
Filed: 1949-01-26
Abstract: Cyanine dyes contain a 2-thio-3-alkyl-5-ketotetrahydrothiazole or corresponding 3-aralkyl nucleus.  The dyes may be prepared by reacting a compound of the formula <FORM:0662775/IV (c)/1> wherein R is an alkyl or aralkyl group, with (a) a quaternary salt of a heterocyclic nitrogen base containing in the a - or g -position to the quaternary nitrogen atom an alkyl thioether group, (b) a quaternary salt of a heterocyclic nitrogen base containing in the a - or g -position to the quaternary nitrogen atom a group of the formula C6H5.NR.(CH=CH)n-, wherein R is an alkyl or acyl group and n is 1 or 2, (c) a heterocyclic nitrogen compound containing in the a - or g -position to the heterocyclic nitrogen atom an external reactive methyl, methylene, mono-substituted methyl, or mono-substituted methylene group and an ortho-ester of a monocarboxylic acid, (d) a compound of the general formula <FORM:0662775/IV (c)/2> wherein D1 is the residue of a 5- or 6-membered heterocyclic nitrogen ring, R is H or an alkyl, aralkyl or aryl group, R1 is an alkyl or aralkyl group, R2 is an alkyl, aralkyl, or aryl group, X is an acid radical, and n is 0 or 1, (e) a compound of the general formula <FORM:0662775/IV (c)/3> wherein R1 is alkyl, R2 is H or an alkyl or aralkyl group, R3 is an alkyl or aralkyl group, D1 is the residue of a 5- or 6-membered heterocyclic nitrogen nucleus, A is an acid radical, and n is 0 or 1, or (f) a p-dialkylaminobenzaldehyde in the presence of a base and a solvent for the reactants.  The dyes may also be prepared by reacting a compound of the formula <FORM:0662775/IV (c)/4> wherein R is an alkyl or aralkyl group, R1 and R2 are alkyl, aralkyl, or aryl groups, and D is the residue of a heterocyclic nucleus, with an alkyl ester to convert the thione group to an alkylmercapto group, and then with a heterocyclic nitrogen compound containing a reactive methyl group or external methylene group in the a - or g -position to the heterocyclic nitrogen atom.  3 - Methyl - 2 - thio - 4 - (p - dimethylaminostyryl) - 5 - ketotetrahydrothiazole is prepared by refluxing together 3-methyl-2-thio-5-ketotetrahydrothiazole, p-dimethylaminobenzaldehyde, and pyridine.  [4 - (3 - Methylisorhodanine)] - [2 - (3 - methyldihydrobenzthiazole)] - merocyanine is prepared by fusing together 2-methylmercaptobenzthiazole and methyl p - toluenesulphonate, adding 3 - methyl 2 - thio - 5 ketotetrahydrothiazole and pyridine, and heating. [4-(3-ethylisorhodanine)]-[2-(3-methyldihydrobenzthiazole) ]-merocyanine, [4 - (3 - methylisorhodanine)] - [2 - (3 - ethyldihydrobenzthiazole) - merocyanine, [4 - (3 - ethylisorhodanine)] - [2 - (3 - ethyldihydro - 41 : 51 - benzbenzthiazole)] - merocyanine, [4 - (3 - ethylisorhodanine)] - [2 - (3 -methyldhydro benzoxazole)]-merocyanine, [4-(3-ethylisorhodanine)]-[2 - (1 - methyldihydroquinoline)] - merocyanine, [4 - (3 - butylisorhodanine)] - [2 - (3 - methyldihydrobenzthiazole)]-merocyanine, [4-(3-benzylisorhodanine)] - [2 - (3 p  - methyldihydrobenzthiazole)] - merocyanine, and [4 - (3 - cyclohexylisorhodanine)]-[2-(3-methyldihydrobenzthiazole) ]-merocyanine are similarly prepared.  [4 - (3 - Methylisorhodanine)] - [2 - (1 : 3 : 3 - trimethylindoline)] - dimethinemerocyanine is prepared by heating together 2-o -ethylthiovinyl - 3 : 3 - dimethylindolenine metho - p - toluenesulphonate, 3 - methyl - 2 - thio - 5 - ketotetrahydrothiazole, and pyridine. [4-(3-Ethylisorhodanine)] - [2 - (1 : 3 : 3 - trimethylindoline)]-dimethinemerocyanine, [4-(3-ethylisorhodanine)]-[2 - (3 - methyldihydrobenzoxazole)] - dimethylmerocyanine, and [4 - (3 - methylisorhodanine)] - [2 - (3 - methyldihydrobenzoxazole)] - dimethinemerocyanine are similarly prepared.  [4-(3-Ethylisorhodanine)] - [2 - (1 : 3 : 3 - trimethylindoline)] - dimethinemerocyanine is also prepared by refluxing together 3-ethyl-2-thio-5-ketotetrahydrothiazole, ethyl orthoformate, and acetic anhydride, adding 2 : 3 : 3-trimethylindolenine methiodide and triethylamine, and boiling.  [4 - (3 - Ethylisorhodanine)] - [2 - (3 - ethyl - 5 - methyldihydrobenzthiazole)]-dimethinemerocyanine is prepared by refluxing together 2-o -acetanilidovinyl - 5 - methylbenzthiazole ethiodide, 3 - ethyl - 2 - thio - 5 - ketotetrahydrothiazole, and pyridine. [4-(3-Methylisorhodanine)]-[2-(3-methyldihydrobenzthiazole) ]-dimethinemerocyanine is similarly prepared. [4-(3-Ethylisorhodanine)]-[2 - (1 - ethyldihydroquinoline)] - dimethinemerocyanine is prepared by heating together 3-ethyl-2 - thio - 5 - ketotetrahydrothiazole, diphenylformamidine and acetic anhydride, adding quinaldine ethiodide and pyridine, and refluxing. [4 - (3 - Ethylisorhodanine)] - [2 - (3 - ethyldihydrobenzoxazole)] - hexamethinemerocyanine is prepared by adding triethylamine to a solution of 2 - o  - acetanilidohexatrienylbenzoxazole ethiodide and 3-ethyl-2-thio-5-ketotetrahydrothiazole in acetic anhydride, and heating.  [2 - (3 - Methylbenzthiazole)] - [2 - (4 - (3 - ethyl-5 - ketodihydrothiazole)} - {2 - (1 : 3 : 3 - trimethylindoline)} - dimethinemerocyanine] - methinecyanine p - toluenesulphonate is prepared by fusing together [4 - (3 - ethylisorhodanine)] - [2 - (1 : 3 : 3 - trimethylindoline)] - dimethinemerocyanine, 2-methylbenzthiazole, and methyl p-toluenesulphonate, dissolving in pyridine, and boiling.  3 - Methyl - 2 - thio - 4 - acetanilidomethylene - 5 - ketotetrahydrothiazole is prepared by boiling together 3 - methyl - 2 - thio - 5 - ketotetrahydrothiazole, diphenylformamidine, and acetic anhydride.  3 - Ethyl - 2 - thio - 4 - o  - acetanilidopentadienylidene-5-ketotetrahydrothiazole is prepared by boiling together 3-ethyl-2-thio-5-ketotetrahydrothiazole, glutaconic aldehyde dianilide hydrochloride and acetic anhydride. 3-Benzyl-2 - thio - 4 - o  - acetanilidopentadienylidene - 5 - ketotetrahydrothiazole is similarly prepared.  [4 - (3 - Benzylisorhodanine)] - [2 - (3 - ethyldihydrobenzthiazole)] - tetramethinemerocyanine is prepared by fusing together 2-methylbenzthiazole and ethyl p-toluenesulphonate, adding malondialdehyde triethylthiomercaptal and acetic anhydride and refluxing, adding 3-benzyl-2-thio-5-ketotetrahydrothiazole and dry pyridine, and refluxing.  [4-(3-Ethylisorhodanine)]-[2 - (3 - ethyldihydrobenzthiazole)] - tetramethinemerocyanine, [4 - (3 - octadecylisorhodanine)] - [2 - (3 - ethyldihydrobenzthiazole)] - tetramethinemerocyanine, [4 - (3 - benzylisorhodanine)] - [2 - (1 - ethyldihydroquinoline)] - tetramethinemerocyanine, [4 - (3 - ethylisorhodanine)] - [2 - (1 - ethyldihydroquinoline)]-tetramethinemerocyanine, [4 - (3 - octadecylisorhodanine)] - [2 - (1 - ethyldihydroquinoline)]-tetramethinemerocyanine, and [4 - (3 - ethylisorhodanine)] - [2 - (3 - methyldihydrothiazoline)] - tetramethinemerocyanine are similarly prepared.  Specifications 426,718, 425,609, 428,359, 489,335, 519,895, 555,936, 562,567, and 662,776, [Group IV (b)], are referred to.  According to the Provisional Specification, the processes of Specifications 470,725, 485,110, 487,051, 540,577, 540,578; 549,202, 557,549, 557,550, [all in Group IV (b)], 624,027, 638,021, 638,022, 638,023, [Group IV (b)], 638,024, and 638,047, and modifications of the process of 489,335 additional to that referred to in the Complete Specification, may be modified to produce dyes containing the 2-thio-3-alkyl- (or aralkyl-) 5-ketotetrahydrothiazole nucleus.