Patent GB-425609-A (GB)
Title: Improvements in or relating to the production and use of dyes having a methine or polymethine linkage
IPC: C09B23/02
Filed: 1933-09-12
Abstract: Dyes containing at least three nitrogen atoms, two of which are contained in the same heterocyclic ring and the third of which is external to that ring and containing a methine or polymethine chain, are prepared, (a) by condensing the quaternary salts of two heterocyclic nitrogen compounds containing complementary reactive groups as specified below; (b) by condensing two molecules of the quaternary salt of a heterocyclic nitrogen compound containing a reactive methyl group with a condensing agent as specified below; or (c) by condensing a quaternary salt of a heterocyclic nitrogen compound containing a reactive methyl group with a p-aminoarylaldehyde, and characterized in each case by using as one or both components of the condensation reaction the quaternary salt of a heterocyclic nitrogen compound containing two nitrogen atoms in the same ring and having one or more reactive groups as specified below attached to a carbon atom (or atoms) in o-position to one, but not to both nitrogen atoms.  Specified reactive groups: methyl, a - or g -alkylmercapto-(Specification 424,559), the reactive grouping of an N-alkyl a - or g -thione quaternary ammonium salt, arylaminovinyl- (prepared by reacting a quaternary ammonium salt of a heterocyclic nitrogen compound containing a reactive methyl group with an arylformamidine), and acetanilidovinyl.  These groups are complementary for the purposes of condensation reactions in the following respects: a thioether (or thione) grouping reacts with a reactive methyl giving a methine linkage; an arylaminovinyl or acetanilidovinyl grouping reacts with a reactive methyl to give a trimethine linkage; a reactive methyl also reacts with an a - or g -halogen derivative of a quinolinium compound giving a methine linkage. Specified condensing agents - ethylorthoformate used in pyridine solution to give a compound having a trimethine linkage; proparylaldehyde diethylacetal used in pyridine solution to give a compound having a pentamethine linkage; anilineacroleinanil used in alcohol solution containing sodium ethoxide to give a compound having a pentamethine linkage; glutaconic aldehyde dianilide used in alcohol solution containing sodium ethoxide to give a compound having a heptamethine linkage.  A modified procedure for effecting the process under (a) above comprises heating a mixture of a heterocyclic nitrogen base containing two nitrogen atoms in the same ring and one or more reactive groups as specified in o-position to one but not to both nitrogen atoms, a further heterocyclic nitrogen base of the same or different type having a specified complementary reactive group, and an alkyl-p-toluenesulphonate to form the quaternary salts, and completing the condensation by adding an acid-binding agent with further heating.  Suitable heterocyclic nitrogen compounds having two nitrogen atoms in the same ring are 2,4-dialkylmercaptopyrimidines, 4 - methyl - 2,6 - dialkylmercaptopyrimidines, 2,4,6 - trialkylmercaptopyrimidines, methylpyrimidines, 4-alkylmercaptoquinazolines, 2,4-dialkylmercaptoquinazoline, 4-methylquinazoline, 2,4-dimethylquinazoline and homologues and analogues, and dialkylmercapto - thio - b .b <1> - diazole; they may be reacted with quaternary salts of substituted or unsubstituted quinaldines, thiazoles, thiazolines, oxazoles, oxazolines, selenazoles, selenazolines, quinolines, indolenines, pyridines, benzthiazoles, naphthizoles, benzoxazoles, and naphthoxazoles containing the specified reactive groupings; other substituent groups may be hydroxy, alkoxy, halogen, alkyl, aryl, aralkyl, amino or substituted amino.  In examples, (1) dimethylmercaptothio - b .b <1> - diazole (prepared by methylation of the dimercaptothiodiazole) is heated, admixed with (a) quinaldine and ethyl-p-toluenesulphonate, and (b) methylbenzthiazole and ethyl-p-toluenesulphonate followed by addition of pyridine with further heating, the dyes being precipitated as the iodides; (2) dimethylmercaptothio - a .b <1> - diazole (prepared by treatment of xanthane hydride with caustic soda and methyl sulphate) is heated admixed with (a) methylbenzthiazole and ethyl-p-toluenesulphonate, and (b) quinaldine and ethyl-p-toluenesulphonate, followed by addition of pyridine and further heating, the dyes being precipitated as the iodides; (3) 4-methylmercaptoquinazoline (quinazolone derived from formamide and anthranilic acid is treated with phosphorus oxychloride and phosphorus pentachloride, then with hydrogen sulphide and finally methylated) is heated in admixture with (a) 1-methylbenzthiazole and ethyl-p-toluenesulphonate, (b) quinaldine and ethyl-p-toluenesulphonate, (c) 1-methylbenzoxazole and ethyl-p-toluenesulphonate, and (d) lepidine and ethyl-p-toluenesulphonate, followed by addition of sodium acetate or pyridine with subsequent heating, the dyes being precipitated as the iodides; (4) dimethylmercaptopyrimidine (prepared by condensing urea with malic acid in presence of sulphuric acid to give uracil, treating this with phosphorus oxychloride, then passing in hydrogen sulphide and finally methylating) is heated in admixture with (a) 1-methylbenzthiazole and ethyl-p-toluenesulphonate and (b) quinaldine and ethyl-p-toluenesulphonate, followed by addition of sodium acetate with subsequent heating, the dyes being precipitated as the iodides; (5) 4-methylquinazoline (prepared by heating o-formylaminoacetophenone with ammonia in alcohol in a sealed tube) is heated in admixture with (a) methylmercaptobenzthiazole and ethyl-p-toluenesulphonate, (b) 4-methylmercaptoquinazoline and methyl-p-toluenesulphonate, followed by addition of pyridine and subsequent heating, the dyes being precipitated as the iodides; or the quinazoline is first heated with ethyl-p-toluenesulphonate and condensed with ethyl-orthoformate in pyridine, or it is first heated with methyliodide and condensed with 2 - acetanilidovinyl - 1,3,3 - trimethylindoleninium iodide (from 2,3,3 - trimethylindolenine methiodide, diphenylformamidine and acetic anhydride) in pyridine, and with p-dimethylaminobenzaldehyde in alcohol; (6) 2,4 - dimethylquinazoline (prepared from o-acetylaminoacetophenone) is heated in admixture with (a) methylmercaptobenzthiazole and methyl - p - toluenesulphonate, and (b) ethylmercaptobenzthiazole, and ethyl-p-toluenesulphonate, followed by addition of pyridine and further heating, the dyes being precipitated as the iodides; or the quinazoline is first treated with ethyl iodide and heated with pyridine and ethylorthoformate.  Samples have been filed under Sect. 2 (5) and prepared as follows: (1) 4 - methylquinazoline methyl - p - toluenesulphonate is condensed with propargylaldehyde diethylacetal in pyridine and the dye precipitated as the iodide; (2) 4-methylquinazoline methyl-p-toluenesulphonate is condensed with b -anilinoacrolein anil in alcohol and in presence of sodium ethoxide, followed by treatment with potassium iodide; (3) 3-o -acetanilidovinylquinazoline methiodide is condensed with 2,3,3-trimethylindolenine methiodide in pyridine and acetic anhydride; (4) 4-methylquinazoline ethiodide is condensed with N-methylquinoline-4-thione ethiodide in pyridine (N-methylquinoline - 4 - thione-ethiodide is prepared by heating 4-chlorquinoline with excess methyliodide, and heating the product with alcoholic potassium hydrogen sulphide followed by heating with ethyliodide); (5) 4-methylquinazoline methiodide is condensed with glutaconic aldehyde dianilide in alcohol and in presence of sodium ethoxide.  The products are sensitizers or desensitizers for photographic emulsions. Thus a film or plate coated with emulsion may be bathed in a solution (1 : 20000 to 1 : 50000) of the dye, or the dye may be added to the emulsion prior to casting (1 to 2 parts per unit of emulsion containing 2800 parts of silver bromide).  The sensitizing properties of a number of the above dyes described in the examples is given. Desensitizing dyes are those containing a nitro group in either of the nuclei.  Specifications 369,947 and 370,388 also are referred to.