METHOD FOR PREPARATION OF L-FENCHONE ANILS Russian patent published in 2021 - IPC C07C249/02 C07C251/20 

FIELD: pharmaceutical industry.

SUBSTANCE: present invention relates to a method for the preparation of L-fenchone anils, which may be of interest as precursors of antiviral agents. The method consists in the interaction of fenchone and an aniline derivative during boiling in the presence of a titanium (IV) derivative, while trifluoromethane sulfonic acid is additionally used in the process, tetraisopropyl ortho-titanate is used as a titanium (IV) derivative, the interaction of L-fenchone, aniline derivative and tetraisopropyl ortho-titanate is carried out in a molar ratio of 1:1.1:0.825 at 175-180°C until the calculated amount of isopropanol is almost completely removed, after which the reaction mixture is cooled to room temperature and treated with methyl tert-butyl ether, the acid is neutralized with a saturated solution of sodium bicarbonate, the titanium oxide precipitate is separated from the organic layer by filtration, the organic layer is washed with a saturated aqueous solution of sodium chloride, filtered through a thin layer of silica gel for thin-layer chromatography, the solvent is removed, and the cubic residue is fractionated in vacuum.

EFFECT: proposed method makes it possible to get the target products with a good yield and purity, using a simplified technology.

1 cl, 5 ex