Solamargine, （25R）-3β-（O-a-L-rhamnopyranosyl-（1--2）-[O-a-L-rhamnopyranosyl-（1--4）]-β-D-glucopyranosloxy}-22a-N- spirosol-5-ene, isolated from the berries of solanum aculeastrum, has been synthesized in 26.8% overall yield. First glycosylation before N-cyclization significantly facilitated synthesis of the desired molecule. We anticipate that this work will provide a new approach to access solamargine and its diversified analogues.
An efficient method for the preparation of 2-deoxy-glycopyranosides was developed by using 2,3-anhydrothioglycosides as the glycosylating agents.The reaction proceeded by the Cu(OTf)_2-mediated rearrangement of 2,3-anhydrothiosugars.And high anomeric stereoselectivity was achieved.The disclosed methodology may find applications in the preparation of many biologically important 2-deoxy-glycosides.
Allyl 4-O-{3-deoxy-3-[4-benzylaminocarbonyl-1H-（1,2,3）-triazol-1-yl]-β-D-galactopyranosyl}-2-deoxy-2-acetamido- β-D-glucopyranoside, a potential inhibitor of galectin-3, was designed and synthesized using lactose as stating material. The modifications of lactose included in introducing of N-acetamino group at the C-2 position through an azidoiodoglycosylation meanwhile constructing the [3-aminolactoside stereoselectively and replacing 3＇-OH with substituent 1,2,3-triazolyl group to enhance the affinity toward galeetin-3.
Novel prodrugs of cyclophosphamide 1a and 1b, which comprised the galactosyl moiety, the key fraction of cyclophosphamide derivates, and the linker 4-hydroxy benzaldehyde, were synthesized. These compounds were anticipated to exhibit amplified anti-tumor activity and targeting ability.
Modified tumor-associated carbohydrate antigens could be used to develop anti-cancer vaccines.Carbohydrate antigens in which thioglycosidic linkages are used instead of O-glycosidic linkages may be more immunogenic and may stimulate the production of antibodies capable of recognizing naturally occurring carbohydrates due to their enhanced resistance to endogenous glycosidases and their inherent non-self antigen character.For this purpose,a new S-linked tumor-associated carbohydrate antigen STn has been successfully synthesized for the first time.
We report a novel P-directing effect of imidazolium based ionic liquid,which was observed when we conducted the glycosylation of a 6-O-acetyl-2,3,4-tri-O-benzyl-mannose trichloroacetimidate donor with a modified ionic liquid support acceptor. The mechanism was investigated and a hypothesis was proposed.After optimization of the reaction conditions,an innovative method for the selective construction of 1,2-cis-β-D-mannopyranosyl linkage was developed.
