ANVENDNING AV 4-(4'-AMINOFENYL)PYRIDINER SOM FERGBILDARE FOR TRYCKKENSLIGT UPPTECKNINGSMATERIAL

摘要

1431493 Compounds used in pressure sensitive recording or copying materials BADISCHE ANILIN- & SODA-FABRIK AG 6 June 1973 [7 June 1972] 27017/73 Heading C4P [Also in Division D2] The dye precursor in a pressure-sensitive recording or copying material is a 4-(41-aminophenyl)-pyridine of general formula in which R1 and R2 are each independently hydrogen or an alkyl or aryl group of one to eight carbon atoms which may bear alkoxy or halogen as a substitute; R3 is hydrogen or alkyl of one to five carbon atoms; R4 is alkyl of 1-4 carbon atoms, haloalkyl of 1-4 carbon atoms, cyanalkyl of which the alkyl moiety contains from 1-4 carbon atoms, an aryl or aralkyl of one to eight carbon atoms which may bear alkoxy as a substitute; R5 and R6 are each independently hydrogen or carbalkoxy or two to five carbon atoms; and R3 and R4 may be closed into a ring. Many examples of specified radicals are given. The dye precursor may be prepared by many conventional methods, for example by condensation of 4-(41-aminophenyl)- pyrylium salts with ammonia or agents which disengage ammonia or by condensation of a 4-aminobenzaldehyde of the general formula or an arylvinylketone of the formula with a ketone of formula in the presence of ammonia or an agent which disengages ammonia. A list of preferred starting materials are given. In one example for the preparation of the dye precursor, pyridine, benzoyl chloride and copper powder are heated for an hour at 100-105‹ C. Methylbenzylaniline is added at 70-80‹ C. and heating at 100-105‹ C. continued. Toluene is added, the resultant precipitate being dissolved in hydrochloric acid. After clarification and recrystallization from ethanol and water, 4-(41-methylbenzylaminophenyl)-pyridine is obtained. In a second example, p-dimethylaminobenzaldehyde, acetophenone and ammonium acetate are heated under reflux in glacial acetic acid. The precipitate is recrystallized from ethanol being 2,6-diphenyl-4-(41-dimethylaminophenyl)-pyridine. The 4-(41-aminophenyl) pyridines may be mixed with another dye precursor, e.g. crystal violet lactone, N-phenyl leucoauramine, N- benzoyl-leucomethylene blue and, in dissolved form micro-encapsulated. The capsules are applied together with a binder to paper. A visible trace on another, acidic, surface results when the capsules are ruptured by pressure.