Chalcomoracin, a Natural Diels–alder Adduct From Diseased Mulberry

Abstract

The structure elucidation of a new phytoalexin, isolated from diseased mulberry leaves and designated as chalcomoracin, is described. The compound is regarded biogenetically as a Diels–Alder adduct of a chalcone, isolated newly from diseased mulberry shoots, and a substituted 2-phenylbenzofuran.

Phenolic Compounds of the Mulberry Tree and Related Plants

“…Five Novel2-Arylbenzofuran Derivatives, Chaicomoracin, Mulberrofurans C, F, G, and H As described in Chapter IV, a series of 2-arylbenzofuran derivatives have been isolated from the mulberry tree. T AKASUGI et al isolated a phytoalexin from diseased mulberry leaves and designated it as chalcomoracin (103) (87). In the course of our studies, three novel 2-arylbenzofuran derivatives, mulberrofurans C (130), F (131), and G (27), were isolated as hypotensive components.…”

Phytoalexins: Enzymology and Molecular Biology

“…In this scheme, the phenylalanine-derived aromatic ring becomes the 2-aryl substituent and not a part of the benzofuran system (564). It was pointed out that alternative mechanisms could not be excluded, and attention was drawn to the possible formation of other arylbenzofurans such as the moracins (CXVII) [phytoalexins from Moms alba (565)] by oxidative cyclization of hydroxystilbenes (564). Next to the isoflavonoids, the stilbenes are the most important class of phytoalexin derived from the shikimate-polymalonate pathway (1 4,566, and the a-, 0-, y-, and'€-viniferins have all been isolated from infected or ultraviolet-irradiated leaves of Vitis viniferu (569)(570)(571).…”

Direct NMR evidence for the equivalent participation of L-phenylalanine and L-tyrosine in the biosynthesis of the intermolecular Diels–Alder type adducts of prenylchalcone and prenylated 2-arylbenzofuran in Morus alba cell cultures

“…In previous papers (1-3), we reported the biosynthesis of optically active intermolecular Diels-Alder type adducts such as chalcomoracin (1) (4,5) and kuwanon J (2) (6) with the aid of Morus alba cell cultures having a high pigment productivity (5).…”