Synthesis of D-Fructofuranosides Using Phenyl Thioglycosides as Glycosyl Donors

: Benzoylated phenyl α - and β - 2-thio-D-fructofuranosides were synthesthed and firstly used as donors in coupling with sucrose acceptor. a-Fructohanoside was stereospecifically synthesized by employing NIS(N - iodosuccinimide)/AgOTf as catalysts. The structure of all products was confirmed by 13C-NMR or 1H-NMR spectrum

Synthesis and Screening of New 5-Substituted-1,3,4-oxadiazole-2-thioglycosides as Potent Anticancer Agents

A series of newly 1,3,4-oxadiazole-2-thioglycoside derivatives were synthesized. The key step of this protocol is the coupling between 5-herteroaryl-1,3,4-oxadiazole-2-thione and activated sugars (cyclic or acyclic sugar analogues) in the presence of basic medium. Among of the synthesized compounds, compounds 7, 10, 11 and 13 were screened for them in vitro anticancer activity against four human cancer cells. MCF-7 (Breast), HEPG2 (Liver), HCT116 (Colon) and HEP2 (Larynx) carcinoma cell lines with IC50 values ranging from 2.08 - 8.72 μg/well. Compounds 11 and 13 were highly specific and potent for four cell lines (MCF-7, HCT116, HEPG2 and HEP2).

Synthesis of 2-Amino-2-deoxy-1,3-dithioidoglycosides via Organocatalytic Relay Glycosylation of 3-O-Acetyl-2-nitrogalactals

Idose-type glycosides have numerous biological activities and have been widely used as anticoagulant drugs and anti-infection drugs.Thioglycosides have enhanced stability for acid-mediated or enzymatic hydrolysis,and have a wide range of applications in glycobiology and drug development.Herein,we describe an efficient method for site-selective and stereoselective synthesis of potential bioactive 2-amino-2-deoxy-1,3-dithioidoglycosides via organocatalysis sequential C3-Ferrier rearrangement and Michael addition of 3-O-acetyl-2-nitrogalactals.Both stepwise and one-pot protocols were carried out and work well.This unique thio-glycosylation protocol highlighted the various advantages,including(i)mild reaction conditions;(ii)excellent site-selectivity and stereoselectivity,good to excellent yields;(iii)broad substrate scopes;(iv)being atom-economic and environmentally friendly;(v)the reactions can be scaled up.

Stereoselective synthesis of the 3,6-branched Fuziα-glucans up to 15-mer via a one-pot and convergent glycosylation strategy

A family of the 3,6-branched Fuziα-glucans including the pentasaccharide repeating unit as well as its di-and trimers were efficiently achieved via a one-pot and convergent glycosylation strategy.All the protectedα-glucans up to 15-mer were assembled with high yields and excellentα-stereoselectivity,which was secured by the synergisticα-directing effects of the Tol SCl/Ag OTf promotion system and the stericβ-facial shielding of bulky saccharide residues linked at the 6-O-position of glucosyl donors.Moreover,the 3,6-branched architecture of glycosyl donor was revealed to be more favorable for theα-selective glucosidation of primary hydroxyl group,especially in the case of large oligosaccharide acceptor.The structurally well-defined syntheticα-glucans would be useful for various biological studies.

A five-component one-pot synthesis of phosphatidylinositol pentamannoside(PIM_5)

A practical and efficient synthesis of phosphatidylinositol pentamannoside （PIM5） was achieved based on a five-component one-pot sequential glycosylation protocol with exclusive regio- and stereo-selectivity. Two regioselective sequential glycosylations on inositol and p-tolyl thioglycosides as the sole type of building blocks made this protocol to avoid the tedious protective group manipulations. This synthetic strategy provides access to other important glycolipids with similar structures.

Synthesis of an antimetastatic tetrasaccharide β-D-Gal-(1→4)-β-d-GlcpNAc-(1→6)-α-D-Manp-(1→6)-β-D-Manp-OMe

An antimetastatic tetrasaccharide β-D-Gal-（1 → 4）-β-D- GlcpNAc-（1 →6）-α-D-Manp-（1 → 6）-β-D-Manp-OMe, was syn- thesized with two approaches. The first approach was a conventional method employing thioglycoside and Koenigs-Knorr glycosylation reaction in 24% overall yield. The second one was a novel route through the azidoiodo-glycosylation strategy by using 2-iodo-2-deoxylactosyl azide as the donor in 36% overall yield.