Synthesis of <i>trans</i>-2,3-dimetho×y-3- (phenylamino)flavanones and related compounds
摘要:
trans-2,3-Dimethoxy-3-(phenylamino)flavanones (2), a new type of flavanone derivatives, are synthesized from flavanones or 2'-hydroxychalcones in two steps, the first one being a condensation with nitrosobenzenes (Ehrlich-Sachs reaction) and the second an oxidation with (diacetoxyiodo)benzene in methanol. Nitrone formation, an important side reaction of the Ehrlich-Sachs reaction, has also been exploited to synthesize 2 simply by use of an excess of nitrosobenzene in aqueous methanol. Syntheses of several analogues of 2 are also reported.