Process for the carbazolation of anthrimides
AssigneeCiba-Geigy Corporation
InventorZdenek Seha
Life of this patent
Estimating the term…
Abstract
There is described a process for producing vat dyes by carbazolation of anthrimides effected by reaction of a complex of titanium tetrahalide (chloride or bromide) with a sulfone in a medium of the sulfone as the solvent. Further subject matter of the invention is a single-vessel process, in which both the production of the anthrimide and the cyclisation thereof can be performed, without isolation of an intermediate, in a sulfone as the reaction medium.
Claims10
A process for the carbazolation of anthrimides, which process comprises carrying out the carbazolation reaction by means of a titanium tetrahalide/sulfone complex in an excess of a sulfone of the formula
- R.sub.1 --SO.sub.2 --R.sub.2 or ##STR7## wherein
- R.sub.1 and R.sub.2 are each a straight-chain or branched-chain alkyl group having 1 to 4 C atoms, and
- X is a straight-chain or branched-chain hydrocarbon chain which has 4 to 10 C atoms and which is unsubstituted or substituted by halogen as the reaction medium.
Dependencies are inferred from the claim text.