Patent GB-862445-A (GB)
Title: Cyanine dyes and photographic emulsions containing them
IPC: G03C1/12
Filed: 1957-09-05
Abstract: Compounds of the general formula:  <FORM:0862445/IV (b)/1> wherein D1 completes a cyclopentane or cyclohexane ring and Q completes a 5- or 6-membered heterocyclic nucleus, are prepared by condensing cyclopentanone or cyclohexanone with a heterocyclic compound of the formula:  <FORM:0862445/IV (b)/2> in the presence of piperidine or a mixture of ammonium acetate and acetic acid.  Solvents such as alcohols, chloroform, 1,4-dioxane or pyridine may be employed. Examples are given of the condensation of cyclopentanone with 1:3-diethyl-barbituric acid, 1:3-diethyl- 2-thiobarbituric acid, 1:3-di(b -methoxyethyl)-barbituric acid, 3-ethyl-rhodanine, 3-phenyl-5-isoxazolone, 3-thionaphthenone-1 ; 1-dioxide and 1-phenyl-3-methyl-5-pyrazolone.  Specifications 704,840 and 862,443 are referred to.ALSO:Cyanine dyes having one of the general formulae:-  <FORM:0862445/IV(c)/1> or <FORM:0862445/IV(c)/2> wherein R and R1 are alkyl, substituted alkyl, aralkyl or aryl groups, R2 is cyano or carbalkoxy, d, m, n and q are 0 or 1, D completes a cycloalkene ring of 5 or 6 carbon atoms, and Q, Z and Z1 complete 5- or 6-membered heterocyclic nuclei, are prepared by reacting a dye of the general formula:-  <FORM:0862445/IV(c)/3> or <FORM:0862445/IV(c)/4> (wherein D1 completes a cyclopentane or cyclohexane ring) with a cyclammonium quaternary salt of the formula:-  <FORM:0862445/IV(c)/5> wherein X is an anion and J is the group -SR3 (R3=alkyl or aryl) or -CH=CH-NR4R5 (R4 is acyl and R5 is aryl).  Alternatively, the symmetrical dyes of formulae I or II may be prepared by reacting two mols of the quaternary salt of formula IV with one mol of a compound of formula:-  <FORM:0862445/IV(c)/6> The dyes of formulae I and II above exist also in an uncharged state. The dyes of formula III above may be prepared by condensing a quaternary salt of the formula:-  <FORM:0862445/IV(c)/7> wherein X1 is an anion and the other symbols are as above, with an equimolecular proportion of a compound of formula VI above.  Examples are given of the preparation of dyes of formula I wherein Q completes a nucleus of 1 : 3-diethyl-barbituric acid, 1 : 3-diethyl-2-thiobarbituric acid, 1 : 3-di (b -methoxyethyl)-barbituric acid, 3-ethyl-rhodanine, 3-phenyl-5-isoxazolone, 3-thionaphthenone-1 : 1-dioxide or 1-phenyl-3-methyl-5-pyrazolone, and of the preparation of dyes of formula II wherein R2 is -CO2C2H5 or -CN. In these examples, Z or Z1 complete benzthiazole, naphthathiazole, naphthaselenazole or benzoxazole nuclei, and R and R1 are methyl or ethyl groups. Examples are also given of the preparations of the intermediate dyes of formula III wherein D1 completes a cyclopentane ring and Q has the values specified above.  It is stated that the dyes of formula II may be hydrolysed with strong sulphuric acid or phosphoric acid to replace the- C(CN)R2 group in the 1-position of the cyclopentene ring with a methyl group, and subsequent treatment with salts such as potassium bromide gives a cyanine dye such as 8, 10-ethylene-3, 31, 9-trimethylthiacarbocyanine bromide. Specification 704,840 and 862,443 are referred to.