Two new benzo-isochromenes, named cichorins B (1) and C (2), were isolated from Cichorium intybus. The structures of the new compounds were elucidated by detailed spectroscopic analysis such as ¹H, ¹³C NMR, COSY, HMQC, HMBC, and HR-EI-MS. Relative configurations of asymmetric centers of cichorins B and C were determined by the analysis of the ¹H NMR coupling constants together with the 2D NOESY and 1D NOE experiments as well as from [α]²⁵(D) value.
Equilibration studies on seven 2,4-disubstituted-RECENTLY, we established1 the constitutions of the natural y-butyrolactones indicate that the cis-isomer is thermo-products, rubrenolide and rubrynolide, isolated from dynamically more stable than the trans-isomer in all cases. Nectandra rubra (Lauraceae) . In order to investigate the relative configurations associated with the lactone rings in
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