Patent ID: 8067622

Claim:
A method for producing naringenin derivatives from xanthohumol or derivatives thereof, which comprises the steps: (1) reaction of xanthohumol or derivatives thereof according to formula (I) hereinafter to give isoxanthohumol or derivatives derived therefrom according to formula (II) hereinafter: where R 1 is an allyl, crotyl, prenyl, geranyl or neryl radical and R 2 is selected from the group consisting of hydrogen, a straight-chain or branched-chain (C 1 -C 6 )-alkyl radical, a (C 3 -C 7 )-cycloalkyl radical, an unsubstituted, monosubstituted or disubstituted phenyl or benzyl radical, where the substituents can be selected from straight-chain or branched-chain (C 1 -C 6 )-alkyl radicals and (C 1 -C 6 )-alkoxy radicals, a (—C(O)—R a ) group, where R a is selected from hydrogen or straight-chain or branched-chain (C 1 -C 6 )-alkyl radicals, and silyl protecting groups, and subsequently (2) demethylation of the compounds according to formula (II), obtaining naringenin derivatives according to formula (III) hereinafter wherein the demethylation is carried out either (A) as base-buffered, Lewis acid demethylation, in which a compound according to formula (II) is reacted with a compound of the general formula MX 3 , where M is a Lewis acid metal ion and X is a halogen, with addition of a base selected from alkali metal alkoxides or tertiary amines, or (B) as protecting-group-supported, Lewis acid demethylation, in which a compound according to formula (II) in which then the radical R 2 independently of one another is a (—C(O)—R a ) group, where R a is selected from hydrogen or straight-chain or branched-chain (C 1 -C 6 )-alkyl radicals, or a silyl protecting group, is reacted with a compound of the general formula MX 3 , where M is a Lewis acid metal ion and X is a halogen, or (C) as a demethylation such that a compound according to formula (II) is reacted with a compound of the general formula LY z , where L is a lanthanide, scandium or yttrium, Y is Hal, OTs, OTf, OTfa, OMs, ClO 4 , BF 4 or PHal 6 and z, depending on the valency of the element L, is an integer from 1 to 4.