摘要:
A simple and efficient synthesis of 4-cyano-8-methoxy-9-methyl-1,3,4,6,11,11a-hexahydro-2H-benzo[b]quinolizine-7,10-dione (20a) as a simple model compound of saframycin A (1) is described starting from the corresponding lactam (16). Reduction of the lactam (16) with lithium aluminum hydride followed by sodium cyanide treatment afforded the alpha-amino nitrile (19) as an inseparable mixture in an excellent yield. Oxidative demethylation of compound (19) with 1ON HNO3 gave the title compound (20a) and its C-4 epimer (20b). The structure of 20a was confirmed by H-1 nmr and C-13 nmr spectroscopic analysis.