Naturally Occurring C-Glycosyl Compounds

Abstract

This chapter discusses naturally occurring C-glycosyl compounds. The first crystalline C-glycosyl compounds from plant sources are barbaloin and scoparin. The true C-glycosyl compounds, such as barbaloin and bergenin, can be typified by the C-D-glucosyl formula in which a carbon atom of group R is attached at C-1, and secondly, compounds may be regarded as derived by simple changes in a C-glycosyl side chain. The latter group contains the vitexin-like compounds assigned a 2, 5 anhydrohexahydroxyhexyl side chain, compounds having a hexahydroxyhexyl side chain. The subsequent purification of the crude product depends on the nature and proportion of the impurities present. Direct crystallization gives a pure product fairly readily with flavone derivatives, and purification by mass paper chromatography or by chromatography on columns of powdered nylon is also sometimes necessary. Most of the C-glycosyl compounds have low solubility in water, considering the number of hydroxyl groups they contain.