Patent GB-423792-A (GB)
Title: Manufacture of cyanine dyestuffs
IPC: C09B23/04
Filed: 1933-07-07
Abstract: Cyanine dyes are prepared by causing a nitrogenous base of the thiazole or quinoline series containing in a -position to the nitrogen atom a reactive bivalant polyatomic grouping of which the atom linked to the said a -position is different from carbon, to react with a quaternary ammonium salt of a heterocyclic base of the thiazole, selenazole, oxazole or quinoline series containing an alkyl group in a - or g -position to the nitrogen atom of the heterocyclic ring.  Specified reactive bivalent polyatomic groupings are <FORM:0423792/IV/1> <FORM:0423792/IV/2> (A standing for halogen or SO4R, and R for alkyl), =N--NO or =NC3H5.  Reaction is effected in the presence of a condensing agent or a solvent, pyridine bases, piperidine, and sodium ethylate being specified in this connection. The products are of use in sensitizing photographic silver halide emulsions. In examples: (1) N-methylthiobenzthiazolone methiodide is condensed with 2-methylbenzthiazole ethiodine in pyridine and with lepidine in pyridine containing a little piperidine; (2) N-ethyl-a -thioquinolone ethiodide is condensed with 2-methylbenzthiazole ethiodide in pyridine; an alcoholic or aqueousalcoholic solution containing about one molar proportion of caustic alkali, piperidine or pyridine is equally effective as a medium for the reaction; in place of 2-methylbenzthiazole ethiodide there may be used quinaldine ethiodide; (3) N-ethyl-p-tolu-a -thioquinolone ethiodide is condensed with 2-ethylbenzthiazole ethiodide in alcohol containing a little piperidine with 2-methylbenzoxazole ethiodide in pyridine and piperidine, with 2-methylbenzselenzaole ethiodide in alcohol, and with 2-methyl-b -anthrathiazole ethiodide in pyridine and piperidine; (4) N-ethyl-2-nitrosoimidobenzthiazoline is condensed with quinaldine ethiodide in pyridine and piperidine; (5) N-ethyl-a -selenoquinolone ethiodide is condensed with 2-methylbenzthiazole ethiodide in alcoholic piperidine. Sensitizing data for these products is given in each case. Thiazoles containing in a -position an alkyl group higher than methyl are prepared by reacting the zinc salts of o-aminophenols with anhydrides of fatty acids containing three or more carbon atoms. Selenazoles containing in a -position an alkyl group higher than methyl are prepared by reaction of o-o<1>-diaminodiphenyldiselenides with anhydrides of fatty acids containing three or more carbon atoms in the presence of zinc.  Oxazoles containing in a -position an alkyl group higher than methyl are prepared by reaction between o-aminophenols and fatty acids containing three or more carbon a atoms. N-alkyl-a -selenobenzthiazones and N-alkyl-a -selenoquinolones are prepared from the corresponding compounds containing oxygen in a -position in place of selenium by reaction with phosphorus pentaselenide; thus N-ethyl-a -selenoquinolone is prepared by heating N-ethyl-a -quinolone with phosphorus pentaselenide. Specification 423,827 is referred to.  The Specification as open to inspection under Sect. 91 comprises the manufacture of cyanine dyes by reacting a nitrogenous base containing in a -position to the nitrogen atom a reactive bivalent atomic grouping with a quaternary ammonium salt of a heterocyclic base containing a reactive methyl group, or with the pseudo-base from such a quaternary ammonium salt.  General formulae assigned to these respective reactants are <FORM:0423792/IV/3> wherein R stands for alkyl, R<1> for vinylene, phenylene, naphthalene, or another polynuclear ring system, Y for the group <FORM:0423792/IV/4> (R1 and R2 being alkyl or aryl), vinylene, oxygen, sulphur or selenium, X for a suitable anion, V for hydrogen, alkyl or aryl and Z for a reactive bivalent atomic grouping.  An additional example describes the condensation of N-ethyl-p-toly-a -thioquinolone ethiodide with lepidine ethiodide in pyridine and piperidine.  This subject-matter does not appear in the Specification as accepted.