Two new methyl chanofruticosinates from Kopsia flavida Blume

Two new indole alkaloids with the methyl chanofruticosinate skeletal system viz., methyl 3-oxo-12-methoxy- N 1 -decarbomethoxy-14,15-didehydrochanofruticosinate ( 1 ) and methyl 3-oxo-11,12-methylenedioxy- N 1 -decarbomethoxy-14,15-didehydrochanofruticosinate ( 2 ), together with four known compounds, methyl 12-methoxy- N 1 -decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate, methyl 11,12-dimethoxychanofruticosinate and methyl 11,12-methylenedioxy- N 1 -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.