Synthesis of sugars embodying conjugated carbonyl systems and related triazole ...

• Author(s): Xavier, N. M. ; Goulart, Margarida ; Neves, Ana ; Justino, Jorge ; Chambert, S. ; Rauter, A. P. ; Queneau, Y.
• Date: 2011
• Persistent ID: http://hdl.handle.net/10400.15/443
• Origin: Repositório Científico do Instituto Politécnico de Santarém
• Subject(s): Bicyclic sugar lactones; Sugar enones; Diene pyranosides; Antimicrobial activity
• Document Type: Article
• Language: English

Description

The synthesis of a series of pyranoid derivatives comprising a conjugated carbonyl function and related triazole derivatives, structurally suitable for bioactivity evaluation, was achieved in few steps starting from readily available carboxymethyl glycoside lactones (CMGL). 3-Enopyranosid-2-uloses were generated by oxidation/elimination of tri-O-acylated 2-hydroxy pyranosides. Subsequent Wittig olefination provided stereoselectively 2-C-branched-chain conjugated dienepyranosides with (E)-configuration around the exocyclic double bond. A heterogeneous CuI/Amberlyst-catalyzed 'click' chemistry protocol was used to convert glycosides bearing a propargyl moiety into the corresponding 1,2,3-triazoles. These new molecules were screened for their in vitro antibacterial and antifungal activities and those containing conjugated carbonyl systems demonstrated the best efficacy. (N-Dodecylcarbamoyl)methyl enone glycerosides were the most active ones among the enones tested. The alpha-anomer displayed very strong activities against Bacillus cereus and Bacillus subtilis and strong activity toward Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The corresponding beta-anomer presented a very strong inhibitory effect against two fungal species (Aspergillus niger and P. aurantiogriseum). (N-Dodecyl-/N-propargyl/or N-benzylcarbamoyl) methyl dienepyranosides exhibited selectively a strong activity toward E. faecalis. Further acute toxicity evaluation indicated low toxic effect of the (N-dodecylcarbamoyl)methyl enone glyceroside alpha-anomer and of the carbamoylmethyl dienepyranosides N-protected with propargyl or benzyl groups