Patent GB-874634-A (GB)
Title: Improvements in photographic reproduction
IPC: C08F2/48
Filed: 1959-08-13
Abstract: Photoconductive resinous compositions comprise one or more di- or tri-phenyl-oxazoles of the general formula: <FORM:0874634/IV (a)/1> wherein R is aminophenyl or dialkyl aminophenyl, R1 is phenyl or substituted phenyl, R2 is H, alkyl, alkenyl or a heterocyclic radical, R3 and R4 are phenyl, aminophenyl or dialkylaminophenyl, and R5 is H or alkyl, together with a resin, and optionally a dyestuff, as in Specification 853,880.  Many suitable oxazoles are listed.  A solvent, e.g. benzene, acetone, methylene chloride or ethylene glycol monomethyl ether, is usually present.  Resins used in the examples include aldehyde-ketone resins, an abietic acid -pentaerythritol resin modified glycerol-maleic acid resin, a zinc modified natural resin, after chlorinated P.V.C. and coumarone resin.ALSO:The preparation is described of aminophenyl-azoles of the following four formulae <FORM:0874634/IV (b)/1> or <FORM:0874634/IV (b)/2> or <FORM:0874634/IV (b)/3> or <FORM:0874634/IV (b)/4> where R is amino phenyl or dialkylaminophenyl, R1 is phenyl or substituted phenyl, R2 is H, alkyl, alkenyl or a heterocyclic radical, R3 and R4 are phenyl or substituted phenyl (at least one being substituted by amino or dialkylamino), and R5 is H or alkyl.  Compounds (I) are made by ring-closing a -benzoylamino-alkyl phenyl ketones (appropriately substituted) with sulphuric acid, or by condensing benzaldehydes with benzaldehyde cyanohydrins in the presence of ethereal hydrogen chloride.  In examples R is p-aminophenyl, p-dimethylaminophenyl or p-diethylaminophenyl, R1 is phenyl or p-chlorophenyl, and R5 is H or methyl.  Compounds (II) are prepared by melting together benzamide and R-substituted phenacyl bromides.  Compounds (III) are obtained by condensing R2CN with appropriately substituted benzoins in the presence or sulphuric or polyphosphoric acid.  In examples R is p-dialkylaminophenyl (alkyl=methyl, ethyl, propyl or butyl), R1 is o- or p-chlorophenyl, and R2 is H, methyl, ethyl, propyl, vinyl or pyridyl.  Compounds (IV) are made in the same way as (III).  In examples R1 is phenyl or chlorophenyl (all 3 isomers), R3 is phenyl, chlorophenyl (all 3 isomers), m-aminophenyl, p-dimethylaminophenyl, p-diethylaminophenyl or p-dipropylaminophenyl, and R4 is phenyl or p-dialkylaminophenyl (alkyl=methyl, ethyl, propyl or butyl). 2-Phenyl-4-(p-diethylaminophenyl)- oxazole is prepared by melting together benzamide and p-nitro-phenacyl bromide to give 2-phenyl-4-(p-nitrophenyl)-oxazole, catalytically reducing this to the p-amino compound and treating the latter with ethyl phosphate. Acylamino-ketones are made by reacting p-dimethylamino-benzoyl chloride with o -amino-acetophenone, p-chloro-o -amino-acetophenone and a -amino-propiophenone respectively.ALSO:A coating composition for electrophotographic plates comprises a natural or synthetic resin and a photoconductive di- or tri-phenyloxazole, in which at least one of the phenyl groups is substituted by amino or dialkylamino. Specified resins include balsam resins, phenol resins, resins modified with colophony, cellulose ethers, polyvinyl, polyacrylic and polystyrene resins, isobutylene polymers, polyesters, phenol-, urea- and melamine-formaldehyde resins, aldehyde resins, ketone resins, polyamides and polyurethanes.  A sensitising dyestuff or chlorophyll may be present.  Specified solvents are methanol, methylene chloride, glycol monomethyl ether, acetone, methyl ethyl ketone, benzene and toluene.  The support may be metal (e.g. aluminium), glass or a resin.  Application may be by roller coating or spraying.