SYNTHESIS OF CHROMANOL DERIVATIVES Russian patent published in 2023 - IPC C07D311/58 

FIELD: chemistry.

SUBSTANCE: invention relates to a process for the preparation of chromanol derivatives, more particularly to a process for the preparation of a compound of general formula I

where R¹, R² and R³ are independently selected from hydrogen and methyl, R⁴ is selected from hydrogen and C₁-C₆-alkanoyl and X is selected from C₁-C₂₀-alkyl and C₂-C₂₀- alkenyl. The proposed method includes stages a)–d). At stage a), a quinone compound of general formula II is provided

and at stage b) catalytic hydrogenation of a quinone compound of formula II is carried out in the presence of hydrogen, a hydrogenation catalyst and a carbonate solvent to obtain a hydroquinone compound of general formula III

/

Next, at stage c), the hydroquinone compound III is reacted with an unsaturated compound of the general formula IV.a or IV.b

where X is as defined above, Y is selected from OH, halogen, -OR¹¹, -SR¹² and -SO₂-R¹², R¹¹ is selected from C₁-C₄-alkyl, C₁-C₄-alkanoyl and trifluoroacetyl and R¹² is selected from C₁-C₆-alkyl, trifluoromethyl and phenyl, where phenyl is unsubstituted or substituted with 1, 2, 3, 4 or 5 radicals selected from halogen and methyl, in the presence of a condensation catalyst, and at the stage d) if R⁴ is selected from C₁-C₆ alkanoyl, the condensation product obtained at Stage c) is reacted with a C₂-C₇ carboxylic acid or C₂-C₇ carboxylic acid anhydride in the presence of an esterification catalyst or reaction of the condensation product obtained at Stage c) with an activated C₂-C₇ carboxylic acid in the presence of a base.

EFFECT: providing a method for producing vitamin E derivatives, which is efficient and provides the desired products with high yield and selectivity without the need to use expensive, corrosive and/or environmentally harmful catalysts and solvents.

17 cl, 2 tbl, 37 ex