Eucomis bicolor

A reaction which involves both ring atoms and substituent is of considerable interest because the substrate is of a naturally occurring class of compounds. 3-Arylidene-chromanones (585) or homoisoflavanones, when heated with nickel in xylene isomerize to the 3-benzylchromone (586) (74IJC281) a number of homoisoflavanones occur in the bulbs of Eucomis bicolor, for example, eucomin (585 R = OH, Ar = 4-MeOC6H4). The stereochemistry about the double bond of compound (585 R = MeO) is altered from (E) to (Z) by irradiation at 300-400 nm (8lFOR(40)l05>. 

The homoisoflavanones belong to a small family of natural products whose first member was isolated by Boehler and Tamm in 1967 from bulbs of Eucomis bicolor Bak. (9). Their discovery resulted from a systematic chemical analysis of Liliaceae for cardiac glycosides. However, unlike the botanically closely related Urginea maritima (L.) Bak. (Squill) and some species of Scilla, Ornithogalum and Dipcadi 33), Eucomis plants did not contain even traces of these compounds. 

Table 8, Incorporation Experiments with Eucomis bicolor...

Fig. 2. Two-dimensional chromatograms of bulb wax phenolics of (A) Eucomis bicolor and (B) E. comosa (see text). The individual numbers refer to the compounds listed in...

Biosynthesis of the 3-Benzylchroman-4-one Eucomin in Eucomis bicolor. Phytochemistry 14, 983 (1975). 

Heller, W., P. Andermatt, W. A. Schaad, and Ch. Tamm Homoisoflavanone IV. Neue Inhaltsstoffe der Eucomin-Reihe von Eucomis bicolor. Helv. Chim. Acta 59, 2048 (1976). 

ScHAAD, W. Isolierung und Ermittlung der Konstitution neuer Homoisoflavanone aus Eucomis bicolor Bak., Ph. D. Thesis, Basel 1977. 

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