New Phragmalin-Type Limonoid Orthoesters from the Bark of Chukrasia tabularis var. velutina

Three new phragmalin-type limonoid orthoesters, velutabularins K-M (1-3) and seven structurally related known compounds were isolated from the bark of Chukrasia tabularis var. velutina. The structures of these compounds were elucidated by spectroscopic analysis. The structure of 1 was confirmed by single crystal X-ray diffraction. In addition, the brine shrimp lethality of compounds 1, 3, and the known compounds was evaluated.