New rhodamine dyestuff cpds. for dyeing polyacrylonitrile fibre - useful for pigmenting plastics, ink or electrophotographic toner or as laser dyestuff, and contg. di:pyrido xanthene ring system, for high light fastness

摘要

New rhodamine dyestuffs are 2,2,4,8,10,10-hexamethyl-6-(2-carboxy phenyl)-1,2,3,4,8,9,10,11-octahydro- dipyrido(3,2-a:3,2-g) xanthylium salts of formula (I). R1, R2 are H or (substd.) 1-4C alkyl; and An(-) is the equiv. of an anion. (I) may be prepd. by the prior art in e.g. J. Org. Chem., vol. 30, pp. 1832-1837, 1965; SU A-548603; and US Application 566924 (29.12.83); examples are given (below). Specifically, R1 is 1-4C alkyl or esp. H; and R2 is H or esp. 1-4C alkyl. (I) may be prepd. by reacting an opt. N-substd. 3-ethoxy aniline with acetone, giving a 7-ethoxy-2,2,4- trimethyl- dihydroquinoline, hydrogenation and treatment with HBr in glacial acetic acid and reaction of the resultant 2,2,4-trimethyl-7-hydroxy- tetrahydroquinoline with e.g. phthalic anhydride. USE/ADVANTAGE - (I) are used for dyeing polyacrylonitrile fibres, for pigmenting polymers or in ink prodn. (claimed). They may also be used as laser dyestuffs or in electrophotographic toner mfr. and have improved properties, esp. high light fastness.