Patent GB-564985-A (GB)
Title: Improvements in or relating to the production of dye intermediates and dyes and to sensitized photographic emulsions
IPC: C09B23/14
Filed: 1943-11-12
Abstract: 2 - Methyl-a - and b  - thionaphthenothiazoles are prepared by reducing a compound of one of the two isomeric formul <FORM:0564985/IV/1> and <FORM:0564985/IV/2> (wherein A is a substituted or unsubstituted phenylene radical) by means of metal, e.g. Zn, Fe or Sn, and acetic anhydride.  The phenylene radical may be substituted by methyl, ethyl, isopropyl, dodecyl, phenyl, naphthyl, benzyl, methylnaphthyl, cyclohexyl, amino, or ether groups, or by halogen atoms.  Compounds of the first formula are produced by brominating first and then nitrating, and compounds of the second formula by nitrating first and then brominating, the compounds being then converted to the disulphides.  2-Methyl-a -thionaphthenothiazole is prepared by refluxing 3 : 31 - dinitro - 2 : 21 - dithionaphthenodisulphide dissolved in acetic anhydride with zinc dust.  2 - Methyl - b  - thionaphthenothiazole is similarly prepared from 2 : 21-dinitro-3 : 31-dithionaphthenodisulphide. 3-Nitrothionaphthene is prepared by nitrating thionaphthene dissolved in acetic acid with a mixture of fuming nitric acid and acetic acid. 3-Bromothionaphthene is prepared by brominating thionaphthene dissolved in chloroform with bromine dissolved in chloroform. 2-Bromo-3-nitrothionaphthene is prepared by brominating 3-nitrothionaphthene dissolved in acetic acid with bromine dissolved in acetic acid.  2-Nitro-3-bromothionaphthene is prepared by nitrating 3-bromothionaphthene dissolved in acetic acid with fuming nitric acid and acetic acid.  3 : 31 - Dinitro - 2 : 21 - dithionaphthenodisulphide is prepared by refluxing 2-bromo-3-nitrothionaphthene with sodium sulphide, sulphur, water, and ethyl alcohol.  2 : 21-Dinitro-3 : 31-dithionaphthenodisulphide is similarly prepared from 2-nitro-3-bromothionaphthene.  Symmetrical methine dyes may be prepared by condensing two or more molecular equivalents of the same 2-methyl-a - (or -b -) thionaphthenothiazole base or quaternary salt in presence of an acid binding agent (with the addition of a salt-forming agent if a base is used) and a compound such as ethyl orthoformate.  Bis - (1 - ethyl - 2 - a  - thionaphtheno - thiazole)-trimethinecyanine chloride is prepared by heating together 2-methyl-a -thionaphthenothiazole and diethyl sulphate, dissolving the melt in a mixture of dry pyridine and ethyl orthoformate and refluxing, and adding saturated ammonium chloride solution to the hot solution.  Bis - (1 - ethyl - 2 - b  - thionaphthenothiazole)-trimethinecyanine chloride is similarly prepared.  Unsymmetrical methine dyes are prepared by condensing one or more molecular equivalents of 2-methyl-a - (or -b -) thionaphthenothiazole base or quaternary salt with one or more molecular equivalents of another heterocyclic nitrogen base or quaternary salt containing a reactive group, a salt-forming agent being added where bases are used.  a - (or -b -) thionaphthenothiazoles containing a reactive methyl group in the a -position to the nitrogen atom may be condensed with a heterocyclic nitrogen base of formula <FORM:0564985/IV/3> (wherein M is a group reacting with a reactive methyl group in cyanine dye condensations and Q either represents the non-metallic atoms to complete a 5-membered heterocyclic nucleus, e.g. a 5-membered nucleus containing at least one nuclear N atom and another divalent atom or group, e.g. O, S, Se, NH, or =C(CH3)2, e.g. a substituted or unsubstituted thiazole, benzthiazole, benzoxazole, naphthathiazole, or anthracenothiazole ring or represents the non-metallic atoms to complete a 6-membered nucleus containing but one non-metallic nuclear atom other than carbon, e.g. pyridine, quinoline or naphthaquinoline; M may be alkylmercapto, alkylselenomercapto, methyl, acetanilidovinyl, halogen, e.g. iodo, or NH2. (1-Methyl-2-a -thionaphthenothiazole) (1 - ethyl - 2 - quinoline) - methinecyanine iodide is prepared by heating together 2 - methyl - a  - thionaphthenothiazole, diethyl sulphate, and 2-methylmercaptoquinoline ethiodide, dissolving the cooled product in ethyl alcohol, and refluxing with addition of triethylamine. Merocyanine dyes are produced by reacting the 2-methyl-a - (or -b -) thionaphthenothiazole derivatives with compounds of formula <FORM:0564985/IV/4> (wherein B is an intracyclic reactive methylene group, W is O, S, or Se and Z either represents the non - metallic atoms to complete a 5-membered nucleus containing 2 nuclear atoms other than carbon, at least one of which is trivalent N and the other is divalent when other than N, e.g. thiazolone, oxazolone, imidazolone, rhodanines, 2 - thio - 2 : 4 - (3 : 5)-oxazoledione, and hydantoins and their N-substituted derivatives and pyrazolones and thiopyrazones, or represents the non-metallic atoms to complete a 6-membered heterocyclic nucleus, e.g. containing 2 nuclear trivalent N atoms such as the barbituric acids.  With such merocyanine dyes the condensation may be repeated as in Specifications 487,051 and 489,335.  Styryl dyes may be made by reacting quaternary salts of 2-methyl-a - (or -b -) thionaphthenothiazole with dialkylaminobenzaldehydes in the presence of basic condensing agents, e.g. pyridine and piperidine.  Isocyanines may be made by reacting quaternary salts of 2-methyl-a - (or -b -) thionaphthenothiazole with quaternary salts of quinoline in presence of alcohol and a strong base (e.g. NaOH), and pseudocyanines by reacting the quaternary salts with quinoline salts containing a reactive halogen atom (e.g. iodine) or an alkylmercapto group.  The methine dyes may be used as sensitizing dyes for silver halide emulsions (e.g. for photolithography and colour photography) and may be used in emulsions containing non-diffusing dye intermediates for colour development and/or azo coupling.  The dyes may also be used as filter and antihalation dyes, and certain of the compounds according to the invention may be used as azo dye intermediates.  The dyes may sensitize to red and blue without conferring green-sensitivity, and may be incorporated in emulsions before or after coating. Sensitizing data are given.  The Specification as open to inspection under Sect. 91 refers also to compounds in which the phenylene group is substituted by amino or ether groups or by halogen atoms, and to merocyanine dyes formed by using second components in which W is Te. This subject-matter does not appear in the Specification as accepted.