Process for producing bismethine isoindolines

Claim 1

A process for producing bismethine isoindolines of the formula ##STR15## wherein T 1 to T 4 are hydrogen or halogen, or one or two of the radicals T 1 to T 4 are alkyl, alkoxy or phenoxy, and R 1 and R 2 independently of one another are each cyano, alkyl- or arylcarbonyloxy, carbamoyl, alkylcarbamoyl, or radicals of the formulae II to IV ##STR16## wherein X 1 is a non-solubilising group, and X 2 and X 3 are hydrogen, halogen, alkyl, alkoxy or alkoxycarbonyl, or together form an --NR'--CO--NR"-- group, in which R' and R" independently of one another are hydrogen or C 1 -C 4 -alkyl, and Y 1 and Y 2 are hydrogen, halogen, alkyl or alkoxy, or together form a fused-on benzene ring, V is oxygen, sulfur, imino or alkylimino having 1 to 4 C atoms, and Z 1 and Z 2 have the meanings of Y 1 and Y 2 , in which process the condensation of 1 mol of a compound of the formula V, VI or VII or of the salts of VI or VII ##STR17## wherein T 1 to T 4 have the meanings defined above, and R 3 and R 4 are identical or different and are C 1 -C 4 -alkyl, or together form the group --CH 2 --CH 2 --, with 2 mols of a cyanomethylene compound of the formula NC--CH.sub.2 --R.sub.1 (VIII) or NC--CH.sub.2 --R.sub.2 (IX), or with 1 mol of a cyanomethylene compound of the formula VIII and 1 mol of a cyanomethylene compound of the formula IX, wherein R 1 and R 2 have the meanings defined above, is performed in a polar solvent in the presence of a strong base, and the bismethine isoindoline obtained is isolated from the reaction mixture by hydrolysis in the presence of an acid.