Flavonoids from Lonchocarpus araripensis (Leguminosae): Identification and Total ¹H and ¹³C Resonance Assignment
Almi F. Lima, Daniele A. Ferreira, Francisco J. Q. Monte, Raimundo Braz-Filho

Abstract
The NMR study of the flavonoids 6a,11a-dihydro-9-methoxy-6H-benzofuran[3,2-C] benzopiran-3-ol (1) and (2,3- cis-3,4-cis-3,4,5,8-tetramethoxy-[1” ,2” : 6,7]-furanoflavan (2) is described. In addition to convencional 1D NMR methods, 2D shift-correlated NMR techniques (COSY, HMQC, HMBC and NOESY) were used for the complete 1H and 13C resonance assignments. The relative stereochemistry at the asymmetric centers was established by nOe difference experiments. The compounds 1 and 2 are novel to Lonchocarpus araripensis.

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