From the bark of Sclerocarya birrea was isolated (-)-epicatechin-3-galloyl ester of which the structure was elucidated by NMR spectroscopy. The compound has secretagogue activity.

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Dienes. -Key step to a novel synthesis of natural carbazoles murrayanine (VII) and murrayafoline A (IX) is the preparation of carbaldehyde (III) via highly regioselective BF3-catalyzed Diels-Alder reaction. -(BENAVIDES, A.; PERALTA, J.; DELGADO, F.; TAMARIZ*,

T o t a l S y n t h e s i s o f t h e N a t u r a l C a r b a z o l e s M u r r a y a n i n e a n d M u r r a y a f o l i n e A Abstract: A new synthesis of the natural carbazoles Murrayanine (1) and Murrayafoline A (3) is described. The key step in the synthetic route involved the regioselective cycloaddition of the diene 4,5-dimethylene-3-phenyl-1,3-oxazolidin-2-one (4) to acrolein (6) catalyzed by Lewis acids at low temperature. Direct aromatization of the substituted cyclohexene moiety of adduct 7, and further hydrolysis of the 2-oxazolidinone ring, proved to be a more efficient strategy than the opposite synthetic sequence for the preparation of the corresponding arylphenylamines 14 and 18. Palladium-promoted cyclization of the latter furnished the desired carbazoles 1 and 3 in high overall yields.

Stereoselective Synthesis, NMR Conformational Study and Diels-Alder Reaction of β-Functionalized 1-Acetylvinylarenecarboxylates.-The stereoselective synthesis of the title compounds (IV) via the vinyl bromide (II) is described. Low temperature NMR experiments and X-ray diffraction of the vinyl amine (IVa) reveal the preference for a planar s-trans conformation. In contrast to the vinyl amines (IV), the intermediate vinyl bromide (II) undergoes Diels-Alder-reaction with dienes in good yields and high stereo-and regioselectivity. -(PERALTA, J.; BULLOCK, J. P.; BATES, R. W.; BOTT, S.; ZEPEDA, G.; TAMARIZ,