Dimeric tetraalkyldistannoxanes are have been reported to catalyze esterification reactions, but are difficult to investigate in detail due to the lack of suitable spectroscopic handles. Electrospray ionization mass spectrometry (ESI-MS), in conjunction with a tethered charge on a tin atom, reveals that immediate decomposition to mono-tin carboxylate compounds occurs in the presence of carboxylic acid.

The magnitude of the stability constants (K) for the formation of X 3 -from X -and X 2 (X = Cl, Br, I) in aqueous and nonaqueous solution depends strongly on both X and solvent. Thermodynamic arguments establish that for aqueous solutions this is not the result of differing bond strengths in the X 3 -anion but rather depends on the solvation energies of the relevant anions and halogens. The experimental results for K in different organic solvents can also be rationalized in terms which emphasise solvation effects. Electrospray ionization mass spectrometry (ESI-MS) has been used to qualitatively probe relative bond strengths in the absence of solvent.Résumé : En solutions aqueuses ou non aqueuses, l'amplitude des constants de stabilité (K) pour la formation de X 3 -à partir de X -et X 2 (X = Cl, Br, I) dépend fortement de la nature de X ainsi que de celle du solvant. Des arguments thermodynamiques permettent d'établir que, dans les cas de solutions aqueuses, cette situation ne résulte pas de diffé-rences dans les forces de liaison dans l'anion X 3 -, mais plutôt des énergies de solvatation des anions et des halogènes appropriés. Les résultats expérimentaux pour les valeurs de K dans divers solvants organiques peuvent aussi être rationalisés en fonction d'effets qui mettent l'accent sur la solvatation. On a utilisé la spectrométrie de masse avec ionisation par électronébulisation pour évaluer qualitativement les forces relatives des liaisons en absence de solvant.

3 , P(OPh) 3 , P(OMe) 3 , PO 3 C 5 H 9 ) are described and the relative importance of carbonyl loss versus phosphine loss as a fragmentation pathway is assessed. Qualitatively, the phosphine ligands bind more strongly to Ir 4 (CO) 11 clusters than to Ru 6 C(CO) 16 . The influence on the collision cell pressure on MS/MS spectra of transition metal carbonyl cluster anions is also explored showing that a greater, simultaneous, distribution of fragment ions is produced as the collision cell pressure is increased.

Several yellow-pigmented species within the family Flavobacteriaceae are commonly associated with diseases in fish and are difficult to speciate due to their fastidious, slow-growing nature and cross-reactive antigens. Here we report the development of specific, antibody-diagnostic tests for Flavobacterium psychrophilum, the aetiological agent of rainbow trout fry syndrome and bacterial cold water disease. A unique antigen from F. psychrophilum, the lipopolysaccharide (LPS) O-polysaccharide (O-PS), formed the basis for the antibody test. LPS O-PS was purified and conjugated to keyhole limpet haemocyanin and bovine serum albumin for the generation of rabbit immune sera and the development of antibody-based diagnostic tests. Rabbit polyclonal anti-O-PS serum was highly specific for F. psychrophilum, without the need for prior cross-absorption with related bacteria and was the basis of an effective ELISA diagnostic test. Antibodies were purified from rabbit anti-O-PS serum and adsorbed onto coloured latex beads for the development of a specific, bead agglutination assay for F. psychrophilum.

There is an urgent demand for 5‐fluorocytosine (5‐FC) due to its activity against HIV‐induced fungal infections as well as its use as a key intermediate in the synthesis of the clinically highly important anti‐HIV drug emtricitabine (FTC). We report a simple, low‐cost five steps synthesis of 5‐FC starting from chloroacetamide. Overall yields up to 46 % were achieved and the route is devoid of any chromatographic purifications. The previously unknown key intermediate (Z)‐2‐cyano‐2‐fluoroethenolate is obtained through a Claisen‐type condensation from fluoroacetonitrile. As the direct cyclization with urea only gave poor yields, 5‐fluoro‐2‐methoxypyrimidin‐4‐amine, 5‐fluoro‐2‐(methylsulfanyl)pyrimidin‐4‐amine and 5‐fluoropyrimidine‐2,4‐diamine served as synthetic intermediates.