Patent GB-447038-A (GB)
Title: Improvements in or relating to the production of dyes of the cyanine type
IPC: C09B23/16
Filed: 1934-08-03
Abstract: Products related to the cyanine dyes but containing one or two nitrogen atoms in the linking chain in place of carbon atoms are prepared by condensing a heterocyclic nitrogen base or its quaternary salt having an amino or imino group in the a - or g -position to the nitrogen atom with (1) a quaternary salt of a further heterocyclic nitrogen compound having an a - or g -reactive aminovinyl- or substituted aminovinyl grouping giving product wherein two heterocyclic nuclei are linked by a conjugated chain of one nitrogen and two carbon atoms, (2) a quaternary salt of a further heterocyclic nitrogen compound having an a - or g - reactive thioether or selenoether grouping (including the reactive grouping of an alkyl salt of an N-alkyl thione or selenone) or with a quaternary salt of a 2-halogenated compound of the quinoline series to give products wherein two heterocyclic nuclei are linked by a nitrogen atom, (3) an aromatic aldehyde giving products wherein a heterocyclic nucleus is linked to an isocyclic nucleus by a conjugated chain of one nitrogen and one carbon atom, or (4) an orthoester of a monocarboxylic acid to give products wherein two heterocyclic nuclei are linked by a conjugated chain of two nitrogen and one carbon atoms.  When in these processes a heterocyclic nitrogen base having a reactive amino or imino group is employed, the resulting base may be subsequently converted to the corresponding quaternary salt.  A modification of the process (2) above comprises condensing the heterocyclic nitrogen base having a reactive amino or imino group, a second heterocyclic nitrogen compound having an a - or g -alkyl mercapto group and an alkyl salt together to obtain simultaneous condensation and formation of a quaternary salt.  Starting materials suitable are amino or imino derivatives and thioether, selenoether, aminovinyl, or substituted aminovinyl derivatives of pyridine, quinolines, naphthaquinolines, thiazoles, oxazoles, selenazoles and their homologues of the benzene, naphthalene and homologous series, including those described in Specification 425,609.  The quaternary salts of products of (2) are termed "cyazines," and of products of (4) are termed "cyadiazines" In examples; (1) 1-aminobenzthiazole is condensed with 2-methylmercaptoquinoline and methyl - p - toluenesulphonate and p 2.1<1>-dimethyl-1.2<1>-thioquinocyazine iodide precipitated out with potassium iodide: (2) 1-methylmercaptobenzthiazole methyl-p-toluene-sulphonate is condensed with N-ethyl-1-imino-benzthiazoline hydrobromide and 2-methyl-2<1>-ethylthiocyazine iodide precipitated out with potassium iodide: (3) 1-aminobenzthiazole is condensed with ethylorthoformate to give 1.1<1> - dibenzthiazolyl - formamidine; this is converted to a quaternary salt by heating with methyl - p - toluenesulphonate; the iodide is formed from this by treatment with potassium iodide: (4) 1.1<1>-dibenzoxazolylformamidine is derived as in (3) from aminobenzoxazole; and similar formamidines are thus obtained from 2-amino-b -naphthathiazole, 1 - amino - a  - naphthathiazole, 1 - amino-5 - ethoxybenzthiazole, and 2-aminothiazole: (5) 1 - aminobenzthiazole is condensed with p-dimethylaminobenzaldehyde to give 2-p-dimethylaminobenzalamino - benzthiazole; treatment with ethyliodide gives an unstable ethiodide; similarly constituted products are derived from p-dimethylaminobenzaldehyde and 2 - amino - b  - naphthathiazole, 2-aminothiazole, 1 - amino - 5 - ethoxybenzthiazole, or 1 - amino - a  - naphthathiazole: (6) 1-methylmercaptobenzthiazole methyl-p-toluene-sulphonate is condensed with 1-aminobenzthiazole to give 1-N-methyl-dihydrobenzthiazolylidine - aminobenzthiazole; similarly constituted products are obtained by replacing the mercaptobenzthiazole body by the 1-methylmercaptobenzoxazole- or 2-methylmer-captoquinoline-methyl-p-toluenesulphonate; (7) 1 - aminobenzthiazole, 1 - methylmercaptobenzoxazole and methyl-p-toluenesulphonate are condensed together and 2.2<1>-dimethyl-thiooxacyazine iodide precipitated by means of potassium iodide: (8) 1-aminobenzoxazole, 1 - methylmercaptobenzoxazole and methyl-p-toluenesulphonate are condensed together and 2.2<1>-dimethyloxacyazine iodide precipitated out by means of potassium iodide: (9) 1-aminobenzthiazole, 1-methylmercaptobenzthiazole and methyl-p-toluenesulphonate are condensed together and the resulting 2.2<1>-dimethylthiocyazine - p - toluenesulphonate converted to the iodide by means of potassium iodide: (10) 1-amino-a -naphthathiazole, 1-methylmercaptobenzthiazole and methyl-p-toluenesulphonate are condensed together and 2.2<1> - dimethyl - 5.6 - benzthiocyazine iodide precipitated out by adding potassium iodide: (11) 2 - amino - b  - naphthathiazole, 1-methyl-mercaptobenzthiazole and methyl-p-toluenesulphonate are condensed together to give 2.2<1>-dimethyl - 3.4 - benzthiocyazine - p - toluenesulphonate: (12) 1 - ethylquinoline - 4 - thione, 1 - aminobenzthiazole and methyl - p - toluenesulphonate are condensed together and 2.1<1>-dimethyl-1.4<1>-thioquinocyazine iodide separated by addition of potassium iodide: (13) 1-aminobenzthiazole is condensed with 1.3.3-trimethyl-2-acetanilidovinylindolenium iodide: (14) 1-aminobenzthiazole-methobromide is condensed with 2-iodoquinoline ethiodide to give 2-methyl-1<1>-ethyl-1.2<1>-thioquinocyazine iodide. Samples have been furnished under Sect. 2 (5) of (a) 1.1<1> - dimethyl - 2.4<1> - cyazine iodide prepared by condensing 2-methylmercaptoquinoline - methyl - p - toluenesulphonate with 4-aminoquinoline methiodide in presence of sodium ethylate: (b) 1.1<1>-dimethyl-4.4<1>-cyazine iodide prepared by condensing N-methylquinoline-4-thione with methyl-p-toluenesulphonate and this product with 4-aminoquinoline methiodide in presence of sodium ethylate: (c) 2.2<1>.7 - trimethylthiocyadiazine - iodide prepared by condensing 1-aminobenzthiazole-methyl-p-toluenesulphonate with ethylorthoacetate.  In the Provisional Specification reference is made to the condensation of the condensation of heterocyclic nitrogen bases or their quaternary salts with compounds containing a nitroso grouping or with formamidines, b -acrolein anils (to give symmetrical, or by a two stage process asymmetrical compounds), glutaconic aldehyde or its dianilide.  British Specifications 424,559, 426,718, 428,359, 431,141, 432,628, German Specification 595,361 and J. Chem. Soc. 125, page 1348 also are referred to. Aminoselenazoles are prepared by condensing selenourea with a monohalogenated ketone such as chloracetone or w-bromacetophenone.  N - ethyl - 1 - iminobenzthiazoline hydrobromide is prepared by condensing ethylaniline hydrochloride with potassium thiocyanate and treatment of the product in chloroform with bromine.  4 - Aminoquinoline - methiodide is prepared by treating 4-chlorquinoline with excess methyl iodide and saturating the product with dry ammonia gas.