1992 Volume 40 Issue 6 Pages 1390-1397
The four stereoisomers of C-nor emetine Pyman (2) were synthesized and isolated as their hydrobromides (2a-d·2HBr). Reduction of 3, 11b-trans dehydro C-nor emetine Pyman (13a) gave an inseparable mixture of 2a and 2b. They were converted into the corresponding 2-phenoxybenzoyl amides (14a, b), and the 3, 11b-trans C1'-epimers, 14a and 14b, were chromatographically separated. Similarly, the 3, 11b-cis C1'-epimers, 14c and 14d, were obtained from cis dehydro C-nor emetine Pyman (13b). The configurations of 14a and 14d were determined by X-ray crystallographic analysis. Reduction of 14a-d with BH3·SMe2 complex and hydrogenolysis over Pd-catalyst followed by treatment with HBr-AcOH gave 2a-d·2HBr in good yields.