Two new meliacarpinins from the roots of Melia azedarach

Two new azadirachtin-type limonoids, 1-methacrylyl-3-acetyl-11-methoxymeliacarpinin (1) and 1-(2-methylpropanoyl)-3-acetyl-11-methoxymeliacarpinin (2), together with the known compounds, meliacarpinin D (3), melianin B (4) and 2 beta,3 beta-dihydroxy-5 alpha-pregn-17(20)-(Z)-en-16-one (5), were isolated from the roots of Melia azedarach. The structures of 1 and 2 were elucidated by analysis of spectroscopic data and comparison of their NMR data with those of 3. Compounds 1 and 5 exhibited significant activity in the brine shrimp lethality test (BST).