CONFORMATIONAL STUDY OF C-2 SYMMETRICAL BENZO[C]PHENANTHRIDINE ALKALOID DERIVATIVES

We report utilization of the phase-sensitive GSQMBC experiment for the study of benzo[c]phenanthridine derivatives. The technique allows det ermination of the C-2 symmetrical structures by observation of two dif ferent scalar interactions between H6 and C6 atoms as well as measurem ent of long range H-1-C-13 coupling constant. A prefered conformation determined using a dihedral angle constraint extracted from the measur ed (3)J(H,C) coupling constant and AMI calculations is discussed.