Structure and stereochemistry of a new cytotoxic polychlorinated sulfolipid from Adriatic shellfish

A detailed analysis of the causative toxins contained in the hepatopancreas of toxic mussels from the northern Adriatic sea has been carried out. Along with some DSP (diarrhetic shellfish poisoning) type toxins, such as okadaic acid, yessotoxin, and their derivatives, which are involved in a number of human intoxications throughout the world, we have now isolated a new cytotoxin, a polychlorinated sulfolipid 1, whose gross structure has been elucidated by spectral analysis, including various 2D NMR techniques. The relative stereochemistry of 1 was elucidated by successful application of the J-based configuration analysis developed for acyclic compounds using carbon-proton spin-coupling constants ((2,3)J(C,H)) and proton-proton spin-coupling constants ((3)J(H,H)); its absolute stereochemistry was established by the Mosher method. Compound 1 possesses in vitro cytotoxicity against WEHI 164 and RAW 264.7 cells.     

Molecular mechanics (MM2) calculations and cone angles of phosphine ligands

Molecular mechanics (MM2) calculations were performed on 54 conformations of 18 phosphines (PH₃; PH_3−nR_n, where n = 1,…3, and R = Me and Et, n = 1 or 2 and R =ⁱPr, and n = 1 and R =^tBu, PMe₂Et, PMeEt₂, and PPhMe₂, and PPh₂R where R = Me, Et, ⁱPr, ^tBu and Ph). The results are compared to those previously obtained from MINDO/3 and MNDO calculations, and to experimental data. Single conformer cone angles and weighted average cone angles were calculated from MM2 optimized geometries employing Tolman's general definition, and they are compared to Tolman's values, MINDO/3 results, and T.L. Brown's E_R values. Of the cone angle definitions used, the weighted average values are suggested as the best single representation of phosphine ligand sizes. The steric parameters (cone angle and E_R values) alone, and in conjunction with electronic parameters, are correlated with experimental data.     

Meeting Report: Ten Years of Atomic and Molecular Science at Elettra

On the 31^st of May and the 1^st of June, 2007, a workshop to celebrate 10 years of atomic and molecular science was held at Elettra. The occasion marked the 10^th anniversary since the first beamtime was officially allocated to a user at the Gas Phase beamline, namely George King of Manchester University. As a satisfied user, King was not only present, but had beamtime during the workshop.