Synthesis and Biological Evaluation of Sugars Containing α,β‐Unsaturated γ‐Lactones

Abstract

The stereocontrolled synthesis of new sugar derivatives carrying the α,β‐unsaturated δ‐lactone (butenolide) moiety is described. Sugar‐fused or sugar‐linked butenolides can be constructed by an efficient reaction sequence involving Wittig olefination of 3‐ or 5‐keto sugars and intramolecular cyclization of the intermediate γ‐hydroxy α,β‐unsaturated esters. The antimicrobial activities of the products and that of a known sugar‐derived pyranoid α,β‐unsaturated δ‐lactone were investigated against six pathogenic bacteria and six fungi. The pyranoid α,β‐unsaturated δ‐lactone 29 proved to be the most active compound in this series towards the plant pathogenic fungi Colletotrichum coffeanum (coffee berry disease) and Pyricularia oryzae (rice blast disease).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Synthesis of sugars embodying conjugated carbonyl systems and related triazole derivatives from carboxymethyl glycoside lactones. Evaluation of their antimicrobial activity and toxicity

“…Data for 20: R f = 0.42 (EtOAc/pentane, 3:2); 1 H NMR (300 MHz, CDCl 3 ) d 6.65 (d,1H,J 4,5 = 1.9),6.61 (br t,1H,NH),1H,2H,5.04 (s,1H,4.96 (td,1H,4.42 (dd,part A of ABX system,1H,J 5,6a = 5.3,J 6a,6b = 11.7),4.32 (d,part A of AB system,1H,J 7a,7b = 15.3),4.23 (dd,part B of ABX system,1H,J 5,6a = 4.7),4.18 (d,part B of AB system 1H,2H,, 2.25 (s, 3H, Me, Ac), 2.10 (s, 3H, Me, Ac); 13 5.89-5.80 (m, 1H, H-10), 5.19 (dq, 1H, H11a, J 11a,11b = J 9a,11a = J 9b,11a = 1.5, J 10,11a = 17.1), 5.11 (dq, 1H, H11b, J 9a,11b = J 9b,11b = J 11a,11b , J 10,11b = 10.3), 4.72 (ddd,1H,2H,J 5,6a = 5.8,J 6a,6b = 11.8,J 7a,7b = 15.6),4.27 (d,part B of AB system,1H,2H,J 5,6a Wittig olefination of the 3-enopyranosid-2-ulose 13 (28 mg, 0.08 mmol) according to general procedure, was completed within 2.5 h. The title compound was obtained as a white solid (19 mg, 56%) after purification by column chromatography (diethyl ether/hexane, 9:1 to diethyl ether). …”

Electrospray ionization mass spectrometric analysis of newly synthesized α,β‐unsaturated γ‐lactones fused to sugars

“…1,19 In this study we aimed to establish fragmentation mechanisms and to propose ion structures using both mass spectrometric data and semi-empirical calculations. These methodologies have been successfully employed in mass spectrometry studies, for example in the fragmentation study of flavonoids and flavonoid diglycosides using both ESI-MS and semi-empirical calculations.…”

Furanose C—C‐linked γ‐lactones: a combined ESI FTICR MS and semi‐empirical calculations study

“…, synthesized according to Xavier et al [15] Sample solutions in methanol HPLC grade acquired from Panreac (Barcelona, Spain) were prepared and acidified with 0.1% (V/V) of formic acid acquired from Fluka (Seelze, Germany).…”

“…[9] The conjugated system can act as a Michael acceptor for the addition of protein functional groups playing a fundamental role in determining bioactivity. [14,15] Besides the biological properties described above, sugars incorporating such moieties have been used as precursors for the synthesis of many bioactive compounds, e.g. branchedchain sugars.…”

“…[26 -30] The knowledge of the fragmentation mechanisms of these sugar lactones and how they behave can be extended to larger and more complex natural products that contain the above mentioned feature in their structure. Hence, we investigated and compared the fragmentation pathways of two butenolides and two β-hydroxy γ -lactones, C-C linked to a furanose ring, [15] using for that purpose electrospray ionization FTICR mass spectrometry.…”