Chuktabrins A and B, Two Novel Limonoids from the Twigs and Leaves of Chukrasia tabularis.

Two novel limonoids, chuktabrin A ( 1), featuring the unique motifs of a 1,3-dioxolan-2-one and a 3,4-dihydro-2 H-pyran, and chuktabrin B ( 2), possessing an unprecedented polycyclic skeleton, were isolated from Chukrasia tabularis. The structures of 1and 2bearing a biosynthetically extended C3 and C2 unit at C-15, respectively, were elucidated on the basis of spectroscopic data, and that of 1was confirmed by a single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]