Four monoterpene alkaloid derivatives from Incarvillea sinensis

Two new derivatives of monoterpene alkaloids, named incarvine D and methoxycarvillateine, and two novel N-oxides, incarvillateine N-oxide and incarvine A N-oxide were isolated from the aerial parts of Incarvillea sinensis LAM. On the basis of chemical and spectroscopic evidence, incarvine D was characterized as the ester of a monoterpene alkaloid, incarvilline, and a monoterpene, tetrahydro-alcohol compound corresponding to Hildebrandt's acid; methoxycarvillateine was established as the methoxy derivative of incarvillateine, and the two oxides were determined to be N-oxide derivatives of incarvillateine and incarvine A, respectively. (C) 1997 Elsevier Science Ltd.