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Sugars that incorporate the unsaturated carbonyl motif have become important synthetic targets not only as a result of their potential biological properties but also as precursors in the synthesis of many bioactive products. Moreover, little is known about the influence of the γ‐lactone moiety in the fragmentation pattern of furanose rings. Therefore, two α,β‐unsaturated γ‐lactones (butenolides) and two β‐hydroxy γ‐lactones, CC linked to a furanose ring were studied using electrospray ionization FTICR mass spectrometry. The behaviour of the protonated and sodiated forms of the compounds under study has been compared considering their structural features. Fragmentation mechanisms were established and ion structures were proposed taking into account the MS2and MS3experiments, accurate mass measurements and semi‐empirical calculations. These inexpensive methods proved to be a valuable resource for proposing protonation sites and for the establishment of fragmentation pathways. Copyright © 2010 John Wiley & Sons, Ltd.

The synthesis of new classes of highly functionalized thiosugar derivatives containing α,βunsaturated carbonyl functions has been accomplished through simple and efficient strategies. 5Thiosugarfused butenolides and a 5thiohex1enopyran3ulose were constructed from easily available starting 3uloses by practical and reliable approaches. The reaction sequence used for the bicyclic fused derivatives involved Wittig olefination of protected pento or hexofuran3uloses, introduction of a sulfhydryl group at C5 of the intermediate unsaturated ester and acidpromoted deprotection, which allowed intramolecular lactonization and conversion into the 5thiopyranose form. For the synthesis of a 5thiohex1enopyran3ulose, a sulfhydryl functionality was introduced at C5 on a masked 3ulose derived from 1,2:5,6diOisopropylideneαDribohexofuranos3ulose. Acidhydrolysis displaced the equilibrium towards the 5thiopentopyran3ulose, which on pyridinemediated acetylation underwent 1,2elimination of acetic acid to give the desired α,βunsaturated 5thiopyranulose. This straightforward pathway provided the target compound in 37  overall yield. © WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009

The behaviour of 2,5dihydroxybenzoic acid 2,5DHB matrix under matrixassisted laser desorptionionisation MALDI conditions was investigated, and the formation of 2,5DHB cluster ions, mainly dehydrated 2,5DHB ions, is reported. Interestingly, in the mass spectra of this compound, besides dimers and trimers, protonated tetramers, pentamers, hexamers and heptamers were also found with significant abundance.The MALDI behaviour of four flavonoids, quercetin, myricetin, luteolin and kaempferol, using 2,5DHB as matrix, was also investigated. The mass spectra of the flavonoids studied revealed a number of flavonoid–2,5DHB cluster ions mainly with the dehydrated 2,5DHB. The number of clusters formed is dependent on the structure of the analyte. For luteolin and kaempferol, in particular, evidence was found for the formation of cluster ions involving retro Diels Alder fragments and intact flavonoids molecules, as well as the corresponding protonated retro Diels Alder fragments with dehydrated DHB molecules. All ion compositions were attributed taking into account high accuracy mass measurements and tandem mass spectrometry experiments. Copyright © 2009 John Wiley & Sons, Ltd.

The stereocontrolled synthesis of new sugar derivatives carrying the α,βunsaturated δlactone butenolide moiety is described. Sugarfused or sugarlinked butenolides can be constructed by an efficient reaction sequence involving Wittig olefination of 3 or 5keto sugars and intramolecular cyclization of the intermediate γhydroxy α,βunsaturated esters. The antimicrobial activities of the products and that of a known sugarderived pyranoid α,βunsaturated δlactone were investigated against six pathogenic bacteria and six fungi. The pyranoid α,βunsaturated δlactone 29proved to be the most active compound in this series towards the plant pathogenic fungi Colletotrichum coffeanumcoffee berry disease and Pyricularia oryzaerice blast disease.© WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008