New C(28) steroidal glycosides from Tubocapsicum anomalum.

Two new C(28) steroidal glycosides, tuboanosides A (1) and B (2), were isolated from the fruit of Tubocapsicum anomalum MAKINO. Their chemical structures were elucidated on the basis of spectroscopic and X-ray diffraction analysis of the p-bromobenzoyl derivative (4) of tuboanosigenin (3), the sapogenol derivative of these two glycosides. Tuboanosides have the structural peculiarity of an unusual side chain carrying an unusual linkage with a C-21 bound to C-25 on the lactone ring.

New C(28) steroidal glycosides from Tubocapsicum anomalum.

Three new C(28) steroidal glycosides, isotubocaposides A (1), B (2), and C (3), were isolated from the fruits of Tubocapsicum anomalum MAKINO. Their chemical structures were elucidated on the basis of spectroscopic and X-ray diffraction analysis of p-bromobenzoyl derivative (5) of isotubocaposigenin (4), the sapogenol derivative of these three glycosides. Isotubocaposides have the structural peculiarity of an unusual side chain carrying a C-21 bound to C-24 on the lactone ring.