Alkaloidal Constituents ofCrinum bulbispermumIII: Bulbispermine, a New Alkaloid ofCrinum bulbispermum¹

Abstract

The structure, relative and absolute configuration of bulbispermine from CRINUM BULBISPERMUM (Amaryllidaceae) is elucidated with spectroscopic techniques and via its methiodide, UV, CD, IR, MS, (1)H- and (13)C-NMR data, [alpha] (20)(D).

Amaryllidaceae alkaloids: Absolute configuration and biological activity

“…The acetoxy group was assigned to be on the C‐11 because of the pronounced deshielding effect on H‐11 observed in comparison with 15 and the long‐range W coupling measured between H‐4a and H‐11‐ endo , which supports the 11‐ exo assignment of the acetoxy group. Bujeine ( 21 ) showed a CD spectrum qualitatively similar to those of some other related (+)‐crinane alkaloids, with a minimum at 252 nm. The 1 H and 13 C NMR spectra were similar to those of 19, with several important differences.…”

“…The structure and stereochemistry of the two alkaloids 22 and 23 was determined by physical and spectroscopic methods and their 1 H and 13 C NMR spectra were completely assigned by means of 2D NMR techniques . Their absolute configuration, having an 5,10b‐ethano bridge (as hamayne, 6‐hydroxycrinamine), was determined by analysis of CD spectra, which were qualitatively similar to those of the α‐5,10b‐ethanophenanthridine alkaloids, displaying a maximum around 290 nm and a minimum around 250 nm . All these alkaloids were assayed for cytotoxic activity and only the main constituent 1 and 6‐hydroxycrinamine were active against BL6 mouse melanoma cells.…”

“…In particular, the structure of 11‐ O‐ acetylhaemanthamine ( 19 ) was assigned by comparing its spectroscopic properties with those of 15 . The absolute configuration of the alkaloid was determined from the CD spectrum, which was qualitatively similar to that of the known (+)‐ 15 (with an α‐ethano bridge), with a minimum at 249 nm . The acetoxy group was assigned to be on the C‐11 because of the pronounced deshielding effect on H‐11 observed in comparison with 15 and the long‐range W coupling measured between H‐4a and H‐11‐ endo , which supports the 11‐ exo assignment of the acetoxy group.…”

“…Bulbispermine ( 27 , Figure ), is a very well‐known alkaloid first isolated from Crinum bulbispermum , and later from Amaryllidaceae species and showing cytotoxic activity against HL‐60 cells . C. bulbispermum is an Amaryllidacea native of South Africa, Lesotho, and Swaziland but is also naturalized in the Lesser Antilles, Honduras, Cuba, and some parts of the USA.…”

“…More recently, a significant amount of 27 was isolated from Zephyranthes robustus, a species of herbaceous flowering bulb commonly known as the Brazilian copper lily, pink fairy lily, the pink rain lily, and native to Brazil, Argentina, and Uruguay, but now naturalized in Florida, Colombia, and South Africa. The structure, relative and absolute configuration of 27 were elucidated by spectroscopic techniques . In particular, the absolute configuration of 27 was assigned by comparing its ORD curve with that of crinamine and haemanthamine ( 15 ) and by chemical transformation into the known diacetylhamaine .…”