62094-86-4

The present invention relates to novel indole derivatives such as compounds of the formula (I): which possess antagonist potency at the 5-HT6 receptor and the use of such compounds or pharmaceutically acceptable salts or solvates thereof in the treatment of Alzheimer's disease and other CNS disorders.

Tetraphenylphosphonium bromide was found to be a suitable catalyst for the reaction of m-nitroaryl derivatives carrying cyano, nitro, chlorocarbonyl, trifluoromethyl, and chlorosulfonyl groups with potassium fluoride in the presence of a stoichiometric amount of phthaloyl dichloride, giving the corresponding m-fluoro aromatic derivatives in good yields.The catalyst was also found to be efficient for the fluorodesulfonylation of m-(fluorosulfonyl)aryl derivatives to afford m-fluoro arenes by the use of a reaction-distillation technique.

Meta-fluoroaromatic compounds were effectively synthesized from m-nitroaromatic or m-fluorosulfonylaromatic compounds by replacement reaction with potassium fluoride in the presence of a catalytic amount of tetraphenylphosphonium bromide.