Resolving structural ambiguity of Oroxylin synthesized by different approaches

Deepa Panhekar, Ganesh D. Maha

Abstract

Oroxylin A (OA) is an O-methylated flavone, a chemical compound found in the medicinal plant Scutellaria baicalensis and the Oroxylum indicum tree. Limited reports are available for the synthesis of Oroxylin A. During synthesis of OA by known methods, ambiguity observed in chromatographic analysis. To resolve this vagueness and investigate the correct structure, OA is prepared using two different methods followed by spectroscopic and spectrometric analysis. The obtained information from LC-MS/MS2 and 2D NMR revealed the difference in the reported structure is due to positional isomers. Principally reported chemical entity does not match the claimed structure when synthesized by reported method, consequently misleading. Hence, the correct structures were established.