Two new methyl chanofruticosinates from Kopsia flavida blume.

Two new indole alkaloids with the methyl chanofruticosinate skeletal system viz., methyl 3-oxo-12-methoxy-N1-decarbomethoxy-14,15-didehydrochanofruticosinate (1) and methyl 3-oxo-11,12-methylenedioxy-N-decarbomethoxy-14,15-didehydrochanofruticosinate (2), together with four known compounds, methyl 12-methoxy-N1-decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate, methyl 11,12-dimethoxychanofruticosinate and methyl 11,12-methylenedioxy-N1-decarbomethoxychanofruticosinate, were isolated in continuing studies on the leaves of Kopsia flavida Blume. The structures of the new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.