A new steroidal glycoside from the seeds of Hyoscyamus niger
A new steroidal glycoside hyoscyamoside G (1), together with two known analogues hyoscyamoside E (2) and hyoscyamoside F1 (3), was isolated from the seeds of Hyoscyamus niger. The structure of 1 was established as (22R,24Z)-1α,3β,7β,22,26-pentakishydroxylergost-22-O-β-d-gulcopyranosyl-5,24-diene-26-O-β-d-glucopyranoside, by means of chemical and spectroscopic methods including HRESI-MS, 1D and 2D NMR. In vitro, compound 2 showed cytotoxicity against human lung cancer cell H460 with IC50 value of 66 μg/mL.
Phytotoxicity of lignanamides isolated from the seeds of Hyoscyamus niger.
Bioassay-guided fractionation of phytotoxic extracts prepared from the seeds of Hyoscyamus niger led to the isolation of three new lignanamides (1-3), along with six known lignanamides (4-9). The structures of the new compounds were determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance techniques, and high-resolution electrospray ionization mass spectrometry. The bioactivity analysis of the isolated compounds showed that compound 3 exhibited significant inhibition on the germination and radical elongation of Allium fistulosum at 10(-4) M concentration.
Unusual (Z)-selective palladium(II)-catalysed addition of aryl boronic acids to vinylaziridines.
The palladium(II)-catalysed addition of arylboronic acids to vinylaziridines has been developed. This reaction proceeds via an insertion/ring-opening process to provide (Z)-allylsulfonamides preferentially. This stereoselectivity is complimentary to existing methods that typically proceed via a SN2' mechanism to yield (E)-allylsulfonamides. Electron-deficient arylboronic acids were the optimum substrates for this reaction, while electron-donating groups on the aromatic ring of the boronic acids resulted in moderate yields.