LUPIN ALKALOIDS .6. STEREOCHEMISTRY OF BIS-QUINOLIZIDINE ALKALOIDS WITH GAMMA-OXO-ALPHA,BETA-ENAMINE SYSTEM

H-1 NMR, H-1,H-1 and H-1,C-13 COSY, and 2D J-resolved spectra of multi florine (1) and 13 alpha-hydroxymultiflorine (2) in CDCl3 were taken. Some erroneously determined chemical shifts in 1 were corrected and fo r the first time signals in 2 were assigned. Most of the coupling cons tants in 1 and 2 were established. A coupling constant of H7-H17 beta and chemical shifts for H17 beta, C14, and C8 were used to define the conformational equilibrium of boat or chair forms in the C rings, in 1 and 2 in solution. The results obtained confirm the previous findings based on chemical shifts of C12: ca. 75 and 70% of the ''boat'' confo rmer in 1 and 2, respectively, at room temperature. Of all the criteri a used, the H7-H17 beta coupling constant seems to be least sensitive to the influence of substituents at rings A and D. From the Haasnoot e quation, torsion angles of HCCH in regions of molecular geometry featu ring low sensitivity to conformational changes were calculated. The hy droxyl group at position 13 alpha has a slight influence on the geomet ry of ring D.