Phenolic constituents of Glycyrrhiza species. Part 10. Glyasperin E, a new 3-phenoxychromen-4-one derivative from the roots of Glycyrrhiza aspera

Abstract

Glyasperin E 1, a new 3-phenoxychromen-4-one derivative, has been isolated from the roots of Glycyrrhiza aspera. The structure of glyasperin E 1 was established first on the basis of spectroscopic evidence and then confirmed by synthesis. Glyasperin E dimethyl ether 1a was synthesized by way of the ring closure of compound 5b with ethoxalyl chloride in pyridine, and then decarboxylation, methylation and prenylation.