Oxygenated bisabolanes from Alpinia densibracteata
摘要:
Seven novel oxygenated bisabolane sesquiterpenes and four oxygenated menthane monoterpenes have been isolated from the dichloromethane extract of Alpinia densibracteata in addition to known bisabolanes and menthanes. The structures of these compounds were established by NMR spectroscopy and by some chemical transformations. (C) 1997 Elsevier Science Ltd.
The large discrepancy between calculated and reported optical rotations for two of four compounds (A-D) described previously as diastereoisomeric p-menth-1-ene-3,6-diols (I–IV) has been resolved by reassignment of configuration to diol B, m.p. 112°, and reassignment of constitution to diol A, m.p. 54°, a p-menth-2-ene-1,6-diol (VI). The set of four diastereoisomeric p-menth-1-ene-3, 6-diols has been