Para-amino-β-cyano-bis-styryl compounds

Claim 1

A compound of formula I, ##SPC7## in which each R 1 , independently, signifies (C 1-6 ) alkyl which is unsubstituted or monosubstituted by halogen, cyano, hydroxyl, alkoxy, phenyl, phenoxy or acyloxy, each R 2 , independently, signifies hydrogen, halogen, (C 1-6 ) alkyl or (C 1-6 ) alkoxy, R 3 signifies a divalent radical of formula --R 5 --R 7 --R 5 --R 7 --R 6 --R 7 --R 5 --R 7 --R 5 -- or R 5 --R 7 --R 6 --R 7 --R 5 -- in which R 6 signifies a direct bond or a divalent radical of formula --O--, --S--, --NR 9 --, --CO--, --O--CO--, --O--CO--O--, --SO 2 --, --NR 8 -- --CO--NR 8 -- or NR 8 --SO 2 --NR 8 , R 4 signifies cyano or acyl, each R 5 , independently, signifies a divalent radical of formula --NR 8 --CO--, --NR 8 --CO--O--, --O--SO 2 --, --NR 8 --SO 2 --, --O--SO 2 --NR 8 -- or has one of the significances given for R 6 , any unsymmetrical divalent radical as R 5 and R 6 being linked either way round, each R 7 , independently, signifies (C 1-6 ) alkylene or alkylidene, of up to 6 carbon atoms which alkylene and alkylidene radicals are unsubstituted or monosubstituted by halogen, cyano, hydroxyl, (C 1-6 ) alkoxy, phenyl, phenoxy or acyloxy, each R 8 , independently, signifies hydrogen, (C 1-6 ) alkyl or, when the chain contains any two R 8 attached to nitrogen atoms which are joined by an ethylene radical as R 7 , the two symbols R 8 , together with the nitrogen atoms and R 7 may join to form a piperazine ring, and R 9 signifies (C 1-6 ) alkylcarbonyl or (C 1-6 ) alkoxycarbonyl, any acyl group as R 4 or as part of an aryloxy group being of the formula R--Y or R'--Z in which R signifies (C 1-6 ) alkyl, Y signifies --O--CO--, --SO 2 -- or --O--SO 2 --, R' signifies hydrogen or (C 1-6 ) alkyl and Z signifies --CO--, --NR'--CO-- or --NR"--SO 2 -- in which R" has one of the significances of R', which molecule is free from acetal groups.