A method of converting (Z)-1-(3,5-disubstituted phenyl)-2-(4-substituted
phenyl)ethene of general formula (II) to (E)-1-(3,5-disubstituted
phenyl)-2-(4-substituted phenyl)ethene of general formula (I)
##STR1##
wherein R.sub.1, R.sub.2, and R.sub.3 are the same or different and
independently represent (C.sub.1 -C.sub.4)alkyl, (C.sub.1
-C.sub.4)alkoxy(C.sub.1 -C.sub.4)alkyl, (C.sub.1 -C.sub.4)alkoxy(C.sub.1
-C.sub.4)alkoxy(C.sub.1 -C.sub.4)alkyl, allyl, vinyl, silyl, formyl, acyl,
aryl(C.sub.1 -C.sub.4)alkyl or substituted aryl(C.sub.1 -C.sub.4)alkyl
group. The present invention also provides a process for the conversion of
(E)-(3,5-disubstituted phenyl-2-(4-substituted phenyl)ethene of general
formula (I) to E-resveratrol of formula (III).
##STR2##
Eine Methode des Umwandelns (Z)-1-(3,5-disubstituted phenyl)-2-(4-substituted phenyl)ethene allgemeiner Formel (ii) zu (E)-1-(3,5-disubstituted stellt phenyl)-2-(4-substituted phenyl)ethene des allgemeinen Formel (i) ## STR1 ##, worin R.sub.1, R.sub.2 und R.sub.3 dieselben sind oder unterschiedliches und unabhängig dar (C.sub.1 - C.sub.4)alkyl, (C.sub.1 - C.sub.4)alkoxy(C.sub.1 - C.sub.4)alkyl, (C.sub.1 - C.sub.4)alkoxy(C.sub.1 - C.sub.4)alkoxy(C.sub.1 - C.sub.4)alkyl, Allyl, Vinyl, Silyl, Formyl, Acyl, aryl(C.sub.1 - C.sub.4)alkyl oder ersetztes aryl(C.sub.1 - C.sub.4)alkyl Gruppe. Die anwesende Erfindung stellt auch einen Prozeß für die Umwandlung von zur Verfügung (E)-(3,5-disubstituted phenyl-2-(4-substituted phenyl)ethene allgemeiner Formel (i) zu E-resveratrol von Formel (iii). ## STR2 ##
