Giuseppe Chiasera

Low‐cost, high‐performance quadrupole mass spectrometer based on a low‐performance rf generator

We describe here a new inexpensive system performing data acquisition as well as process control of a quadrupole mass spectrometer for relatively high molecular weight compounds. The system, based on an ordinary 8‐bit personal computer, performs particularly well in terms of mass scale stability, in spite of the use of a cheap, low‐stability rf generator, thanks to newly designed hardware and software.

Epinardins A-D, new pyrroloiminoquinone alkaloids of undetermined deep-water green demosponges from pre-Antarctic Indian ocean

Abstract Four novel pyrroloiminoquinone alkaloids that differ from members of the discorhabdin/prianosin family for having an allylic alcohol functionality in place of the enone system, epinardins A-D (8–11), have been isolated from undetermined deep-water green demosponges collected in pre-Antarctic waters near the Crozet Islands. Relative stereochemistry has been fully assigned from high-field NMR spectra. Epinardin C (10) proved strongly cytotoxic towards doxorubicin-resistant L1210/DX tumoural cells in vitro.

Almazole A and almazole B, unusual marine alkaloids of an unidentified red seaweed of the family delesseriaceae from the coasts of Senegal

Abstract Almazole A 1 -slowly equilibrating in solution between the major Z 1a and the minor E 1b forms- and almazole B 2 , unusual marine alkaloids for embodying a 2,5-disubstituted oxazole ring, were isolated from an unidentified red seaweed of the family Delesseriaceae from the coasts of Senegal.

GLUTATHIONE S-TRANSFERASE CATALYSED DEHALOGENATION OF HALOAROMATIC COMPOUNDS WHICH LACK NITRO GROUPS NEAR THE REACTION CENTRE

Abstract A comparative kinetic study of the rat-liver glutathione S -transferase catalysed dehalogenation of fluoro- and chloroaromatic compounds showed no significant decrease of the F Cl mobility ratio on going from substrates that carry an ortho -nitro group to those which lack nitro groups near the reaction centre. This suggests a so far unrecognized activity of S -transferases in providing “solvation” for the leaving halide anion at the hydrophobic reaction centre.

Joalin, the first nitrogen-containing xenicane diterpene isolated from a brown seaweed collected off the Senegalese coast

Joalin (–)-1 isolated from a brown seaweed, Dictyota sp., collected off the Senegalese coast, is a rare xenicane-derived diterpene in that it contains nitrogen.