Patent GB-813178-A (GB)
Title: Improvements in photographic sensitizing dyes and intermediates thereof
IPC: G03C1/12
Filed: 1955-11-02
Abstract: The invention comprises compounds of the formula: <FORM:0813178/IV (b)/1> and the quaternization products thereof: <FORM:0813178/IV (b)/2> where R is alkyl, aryl or benzyl, R1 and R2 are aryl, R3 is alkyl and X is an anion.  The compounds of the first formula are obtained by condensing thiophosgene with an N-substituted desylamine R-NH-CR2=CR1-OH, preferably one in which R is C1-C12 alkyl and R1 and R2 have 6-7 carbon atoms.  Quaternation is effected by heating with R3X.  The desylamines are usually taken as hydrohalide salts, from which the free bases are liberated by alkali before use.  Examples show the production of 3-n-butyl-4 : 5-diphenyl-, 3-ethyl-4 : 5 - diphenyl -, 3 : 4 : 5 - triphenyl -, 3 ethyl - 4 - p - methoxyphenyl - 5 - phenyl - and 3 - ethyl - 4 - phenyl - 5 - p - methoxyphenyl - oxazoline-2-thione, the last two being obtained as mixtures and separated by chromatography.  Quaternary salts obtained are 3-n-butyl-2-methylthio - 4 : 5 - diphenyl -, 3 - ethyl - 2 - methylthio - 4 : 5 - diphenyl - and 2 - methylthio - 3 : 4 : 5 - triphenyl - oxazolium methylsulphate.  The Specification also describes the quaternation with ethyl toluene-p-sulphonate of 2-methyl-4 : 5-diphenyloxazole and 4-p-methoxyphenyl-2-methyl-5-phenyloxazole.  It is stated that R may also be methyl, n-propyl, isopropyl, n-octyl, n-dodecyl or tolyl, R1 and R2 may be tolyl or p-chlorophenyl, R3 may be ethyl, n-propyl or n-butyl, and X may be chloride, bromide, iodide, ethylsulphate, benzenesulphonate or toluene-p-sulphonate.  A mixture of N-substituted-desylamines is obtained by heating p-methoxybenzoin with ethylamine.ALSO:Cyanine dyes of the formula <FORM:0813178/IV (c)/1> and merocyanine dyes of the formula <FORM:0813178/IV (c)/2> where R is alkyl, aryl or benzyl, R1 and R2 are aryl, R4 is alkyl, X1 is an acid radical, d is 0 or 1, and Q and Z represent the atoms necessary to complete a 5- or 6-membered heterocyclic ring, are prepared by condensing an oxazolium salt of the formula <FORM:0813178/IV (c)/3> with a compound of the formula <FORM:0813178/IV (c)/4> or <FORM:0813178/IV (c)/5> respectively.  R3 being alkyl and X an acid radical. Examples show the condensation of 3-ethyl-2-methylthio-4 : 5-diphenyloxazolium methylsulphate with 2-methyl - 3 - ethyl - 4 - p - methoxyphenyl - 5 - phenyloxazolium toluene - p - sulphonate and 2 - methyl - 3 - ethyl - 4 : 5 - diphenyloxazolium toluene-p-sulphonate.  The condensation is preferably carried out in the presence of a tertiary base and a lower alcohol, dioxane or pyridine as solvent.  The ring system completed by Z may in general be thiazole, oxazole or selenazole (or benzo- or naphtho-derivatives of these), thianaphtheno-thiazole, quinoline, isoquinoline, indolenine or pyridine and that completed by Q may be thiazolidine, oxazolidine or imidazolidine.  Many suitable substituents on these rings are mentioned.  Suitable groups denoted by the symbols R and X are also listed, e.g. R1 and R2 may be tolyl or p-chlorophenyl.  It is stated that merocyanine dyes can be obtained by condensing (1) 3-ethyl-2-methylthio-4 : 5-diphenyloxazolium methylsulphate with 3-ethyl-2 - thio - oxazolid - 4 - one, 3 - ethylrhodanine, 1 : 3 - diethyl - 2 - thiohydantoin and 3 - carboxymethyl - rhodanine; (2) 3 - n - butyl - 2 - methylthio - 4 : 5 - diphenyloxazolium methylsulphate with 3-ethoxycarbonylmethylrhodanine; and (3) 2 - methylthio - 3 : 4 : 5 - triphenyloxazolium methylsulphate with 3-ethoxycarbonylmethyl-rhodanine.