C-Glycosylflavonoids. The chemistry of orientin and iso-orientin

1. The structures of orientin and iso-orientin have been investigated by periodic acid and ferric chloride oxidation of the tetra-O-methyl derivatives and by identification of the products of oxidation. 2. The preparation and properties of the 3‣,4‣,7-trimethyl ethers of orientin and iso-orientin are described, and the nuclear-magnetic-resonance spectra of orientin, iso-orientin and their tri- and tetra-O-methyl derivatives are discussed. 3. Orientin and iso-orientin are formulated as 8- and 6-C-beta-d-glucopyranosyl-luteolin respectively.