Exhaustive examination of the flavonoid content of the bark of Dalbergia nitidula revealed, amongst other substances a mixture of eight novel and complex (3S)-isoflavans [leiocin, leiocinol, nitidulin, nitidulan, heminitidulan] and (6aS,11aS)-pterocarpans [nitiducarpin, hemileiocarpin, nitiducol]. These insoflavonoids all possess the equivalent of prenyl or geranyl side-chains, which, with one exception, are cyclized to stereochemically related 2H-pyran moeities during biogenesis. Structures determined by physical means were substantiated for the isoflavans by a single synthesis.
No takes yet. Share an insight, caveat, or question.
Heerden et al. (1978) studied this question.