RESUMEN
Inulin-type fructooligosaccharides (FOSs) constitute an abundant subgroup of fructans with important biological activities. However, the availability of individual fructooligosaccharides with an accurate structure in high purity and quality remains challenging. We herein report the first iterative synthesis of five inulin-type FOSs with degrees of polymerization ranging from 3 to 7 via highly stereoselective ß-(2 â 1)-d-fructofuranosylation on a gram scale. Central to the synthesis is the decisive use of the 1-O-TIPS-6-O-picoloyl-protected fructofuranosyl thioglycoside donor, which assured the excellent ß-selective glycosylation by the hydrogen-bond-mediated aglycone delivery (HAD).
Asunto(s)
Inulina , Oligosacáridos , Inulina/química , Oligosacáridos/química , Fructanos , GlicosilaciónRESUMEN
A series of 5H-thiazolo[3,2-a]pyrimidin-5-ones were synthesized by the cyclization reactions of S-alkylated derivatives in concentrated H2SO4. Upon treatment of S-alkylated derivatives at different temperatures, intramolecular cyclization to 7-(substituted phenylamino)-5H-thiazolo[3,2-a]pyrimidin-5-ones or sulfonation of cyclized products to sulfonic acid derivatives occurred. The structures of the target compounds were confirmed by IR, ¹H-NMR, (13)C-NMR and HRMS studies. The compounds were evaluated for their preliminary in vitro antibacterial activity against some Gram-positive and Gram-negative bacteria and screened for antitubercular activity against Mycobacterium tuberculosis by the broth dilution assay method. Some compounds showed good antibacterial and antitubercular activities.
Asunto(s)
Antibacterianos/síntesis química , Antibacterianos/farmacología , Antituberculosos/síntesis química , Antituberculosos/farmacología , Antibacterianos/química , Antituberculosos/química , Bacterias Gramnegativas/efectos de los fármacos , Espectroscopía de Resonancia Magnética , Espectrometría de Masas , Pruebas de Sensibilidad Microbiana , Mycobacterium tuberculosis/efectos de los fármacos , Espectroscopía de Protones por Resonancia Magnética , Espectrofotometría Infrarroja , Ácidos Sulfónicos/químicaRESUMEN
We have developed a cyanide-free strategy for the synthesis of glycosyl carboxylic acids, which can provide 1,2-trans or 1,2-cis glycosyl carboxylic acids and is compatible with common protecting groups. The synthetic utility was demonstrated by the synthesis of 12 unreported glycosyl acids and the total synthesis of scleropentaside A.