Chromenoflavanones from Milletia ovalifolia

The Flavonoids

“…While the 4-substituted compound (6.153) (Gupta and Krishnamurti, 1977b) along with several other ftavonoids having similar substitution patterns. It seems reasonable to suggest biosynthesis from aB-ring unsubstituted precursor which resembles pongamol (6.149) through reduction of the ß-keto function followed by O-methylation.…”

“…(6.26, 627, 628) ) Star et al (1975a Suri et al o ( 6.10) The furano derivative (6.8) represents a rare structure, at least amongst the minor flavonoids. Somewhat more common are furanochalcones such as 'ovalitenin-A' (6.10) which occurs in Milletia ovalijo/ia (Leguminosae) seeds along with other flavonoids having the same A-ring substitution, namely compounds 'ovalitenin-B' (6.156), 'ovalitenin-C' (6.77) and 'ovalitenone' (6.148) (Gupta and Krishnamurti, 1977b). Compound (6.11) is a simple extra-hydroxylated chalcone isolated from Zuccagnia punctata (Leguminosae) by Pederiva et al (1975).…”

“…'Licodione', isolated from the roots and from cultured cells of Glycyrrhiza echinata by Furuya et al (1976), is 2,4,4' -trihydroxybenzoylmethane (6.147). 'Ovalitenone' (6.148) is known from both Milletia ovalifolia (Gupta and Krishnamurti, 1977b) and Pongamia glabra Garg et al, 1978;Sharma and Parthasarthy, 1977) where it occurs with 'pongamol' (6.149) . Traub and Geiger (1975) reported the existence of 2,5,7,3',4' -pentahydroxyflavanone 5-0-g1ucoside in seeds of Galega oJJiänalis 348 The Flavonoids (Leguminosae), but represented it as being in equilibrium with the corresponding dibenzoylmethane glucoside (6.151).…”

“…A complex series of C-alkylated ftavanones, all possessing the 3',4' -methylenedioxy function, has been studied by Gupta and his colleagues (Gupta and Krishnamurti, 1976b;Islam et al, 1980). The compounds are from Milletia ovalifolia and are 'ovalichromene-A' (6.229), 'ovalichromene-B' (6.230), 'ovaliftavanone-C' (6.231) and 'ovaliftavanone-D' (6.232 (Table 6.6) and has recently been reported from members of the Athyriaceae and Dryopteridaceae (Hiraoka, 1978).…”

“…) R I = R2 = H (6.162) RI = CH 3 , R 2 = H (6.163) R I = H, R2 = OCH 3 (6.164) R I = CH 3 , R 2 = OCH 3 henylation of the parent compound at position 8 affords flavanone(6.165) while prenylation at both positions 6 and 8 gves (6.166); both compounds occur in Milletia ovalifolia where they occur with the dimethylchromenoflavanone (6.167)(Gupta and Krishnamurti, 1976a). 'Isolonchocarpin'(6.168) is the product of cyc1ization ofthe prenylated flavanone (6.165) and has been found inHO RI --{ > o (6.167) R = OCH 3 (6.168) R = H…”