Aim To develop a concise method for the synthesis of bicyclic azasugar and thiosugar with novel scaffold. Methods The two primary hydroxyl groups of compound 1 were selectively protected with tosyl cloloride in pyridi...Aim To develop a concise method for the synthesis of bicyclic azasugar and thiosugar with novel scaffold. Methods The two primary hydroxyl groups of compound 1 were selectively protected with tosyl cloloride in pyridine, followed by ring-closure with sodium sulfide or primary amine to form the oxy-bridged bicyclic molecules in good yields. Results Two bicyclic azasugars and a thiosugar were produced from L-sorbose in several steps. Conclusion The described procedures provide an efficient method to synthesize bicyclic azasugar and thiosugar with novel scaffold as potential glycosidase inhibitors.展开更多
The 3＇-OH, 4＇-OH and 2＂-OH of kanamycin A were modified in search of new aminoglycosides to overcome resistant enzymes, ANTs and APHs. The key intermediate was a dibenzylidene-protected derivative of kanamycin A. T...The 3＇-OH, 4＇-OH and 2＂-OH of kanamycin A were modified in search of new aminoglycosides to overcome resistant enzymes, ANTs and APHs. The key intermediate was a dibenzylidene-protected derivative of kanamycin A. The aimed sites were masked by benzyl, methyl and allyl groups. Multi-step reactions gave the desired aminoglycoside derivatives but showed less antibiotic activity than kanamycin A.展开更多
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 ...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.展开更多
Aim To optimize the reaction condition for preparation of 3-spiro-1, 3, 4-oxadiazole substituted fructose and hydrolysis of its isopropylidenes stepwisely. Methods Cyclohexane was added to the reaction mixture every 8...Aim To optimize the reaction condition for preparation of 3-spiro-1, 3, 4-oxadiazole substituted fructose and hydrolysis of its isopropylidenes stepwisely. Methods Cyclohexane was added to the reaction mixture every 8 h to remove acetic acid at 90 ℃. The isopropylidenes were hydrolyzed in 80% AcOH at 60 ℃ stepwisely in a reaction time- dependent manner. Results The yields of cyclization products 1b and 1c were improved from 53% and 51% to 74% and 79% respectively. The 1, 2-di-O-isopropylidene product 3 was obtained after 1 h and the total deprotected product 4 was obtained after 3 h in 80% AcOH at 60 ℃. Conclusion The yield of 1 is improved by cyclohexane-aided azeotropic removal of AcOH from the reaction mixture. Deprotection of 1 in 80% AcOH at 60 ℃ gives 3 or 4 after different time periods.展开更多
Aim To develop a novel selective protection strategy for the synthesis of ribostamycin cyclic carbamate derivatives. Methods Ribostamycin protected by carbobenzoxy group was treated with Nail, to give different protec...Aim To develop a novel selective protection strategy for the synthesis of ribostamycin cyclic carbamate derivatives. Methods Ribostamycin protected by carbobenzoxy group was treated with Nail, to give different protected intermediates under respective controllable cyclization reaction conditions. New ribostamycin derivative was obtained after the cleavage of carbobenzoxy groups. Result The novel selective protection of ribostamycin was achieved by the synthesis of protected intermediates. New ribostamycin derivative was obtained, but showed no expected antibacterial activity. Conclusion Several ribostamycin cyclic carbamate derivatives were obtained by novel selective protection strategy, which shows the practicability and convenience of the protection strategy. But these new ribostamycin derivatives containing cyclic carbamates structure may not be an ideal leading compound for antibiotic activity.展开更多
A core trisaccharide of laminin, β-D-Gal-（1→4）-β-D-GlcpNAc-（1→6）-α-D-Manp-OMe, with potential anti-rumor metastatic activity was designed and prepared. 2-Iodoglactosyl azide was used as the donor to construct...A core trisaccharide of laminin, β-D-Gal-（1→4）-β-D-GlcpNAc-（1→6）-α-D-Manp-OMe, with potential anti-rumor metastatic activity was designed and prepared. 2-Iodoglactosyl azide was used as the donor to construct 2-N-acetamido-2-deoxylactosyl moiety through an azidoiodo-glycosylation reaction. Simultaneously, 1, 2-trans-β-glycosic bond was formed stereoselectively in one step with a moderate yield. This novel procedure avoided the use of 2-amino-2-deoxyglucose as both donor and acceptor.展开更多
Three divalent β-D-galactopyranosyl-（1 → 4）-β-D-glucopyranosides were synthesized using acetylated lactosyl bromide as donor and polyethylene glycols with different polymeric degree （n = 4, 5, 6） as linker, and...Three divalent β-D-galactopyranosyl-（1 → 4）-β-D-glucopyranosides were synthesized using acetylated lactosyl bromide as donor and polyethylene glycols with different polymeric degree （n = 4, 5, 6） as linker, and evaluated for in vivo inhibitory activity to leukocyte-endothelial cell adhesion on severe bum-shock rats. The result showed that the length of linkers had apparent influence on anti cell adhesion activity.展开更多
基金We thank the National Science Foundation of China(NSFC,N0.20372003)for financial support.
文摘Aim To develop a concise method for the synthesis of bicyclic azasugar and thiosugar with novel scaffold. Methods The two primary hydroxyl groups of compound 1 were selectively protected with tosyl cloloride in pyridine, followed by ring-closure with sodium sulfide or primary amine to form the oxy-bridged bicyclic molecules in good yields. Results Two bicyclic azasugars and a thiosugar were produced from L-sorbose in several steps. Conclusion The described procedures provide an efficient method to synthesize bicyclic azasugar and thiosugar with novel scaffold as potential glycosidase inhibitors.
基金National Basic Research Program(973 Program,Grant No.2004CB518904).
文摘The 3＇-OH, 4＇-OH and 2＂-OH of kanamycin A were modified in search of new aminoglycosides to overcome resistant enzymes, ANTs and APHs. The key intermediate was a dibenzylidene-protected derivative of kanamycin A. The aimed sites were masked by benzyl, methyl and allyl groups. Multi-step reactions gave the desired aminoglycoside derivatives but showed less antibiotic activity than kanamycin A.
基金National Natural Science Foundation of China(Grant No.20732001 and 90713004).
文摘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.
文摘Aim To optimize the reaction condition for preparation of 3-spiro-1, 3, 4-oxadiazole substituted fructose and hydrolysis of its isopropylidenes stepwisely. Methods Cyclohexane was added to the reaction mixture every 8 h to remove acetic acid at 90 ℃. The isopropylidenes were hydrolyzed in 80% AcOH at 60 ℃ stepwisely in a reaction time- dependent manner. Results The yields of cyclization products 1b and 1c were improved from 53% and 51% to 74% and 79% respectively. The 1, 2-di-O-isopropylidene product 3 was obtained after 1 h and the total deprotected product 4 was obtained after 3 h in 80% AcOH at 60 ℃. Conclusion The yield of 1 is improved by cyclohexane-aided azeotropic removal of AcOH from the reaction mixture. Deprotection of 1 in 80% AcOH at 60 ℃ gives 3 or 4 after different time periods.
基金The National Basic Research Program(973Program,Grant No.2004CB518904).
文摘Aim To develop a novel selective protection strategy for the synthesis of ribostamycin cyclic carbamate derivatives. Methods Ribostamycin protected by carbobenzoxy group was treated with Nail, to give different protected intermediates under respective controllable cyclization reaction conditions. New ribostamycin derivative was obtained after the cleavage of carbobenzoxy groups. Result The novel selective protection of ribostamycin was achieved by the synthesis of protected intermediates. New ribostamycin derivative was obtained, but showed no expected antibacterial activity. Conclusion Several ribostamycin cyclic carbamate derivatives were obtained by novel selective protection strategy, which shows the practicability and convenience of the protection strategy. But these new ribostamycin derivatives containing cyclic carbamates structure may not be an ideal leading compound for antibiotic activity.
基金National Science Foundation of China (Grant No.20732001 and 90713004).
文摘A core trisaccharide of laminin, β-D-Gal-（1→4）-β-D-GlcpNAc-（1→6）-α-D-Manp-OMe, with potential anti-rumor metastatic activity was designed and prepared. 2-Iodoglactosyl azide was used as the donor to construct 2-N-acetamido-2-deoxylactosyl moiety through an azidoiodo-glycosylation reaction. Simultaneously, 1, 2-trans-β-glycosic bond was formed stereoselectively in one step with a moderate yield. This novel procedure avoided the use of 2-amino-2-deoxyglucose as both donor and acceptor.
基金National Natural Science Foundation of China(No.20372003)
文摘Three divalent β-D-galactopyranosyl-（1 → 4）-β-D-glucopyranosides were synthesized using acetylated lactosyl bromide as donor and polyethylene glycols with different polymeric degree （n = 4, 5, 6） as linker, and evaluated for in vivo inhibitory activity to leukocyte-endothelial cell adhesion on severe bum-shock rats. The result showed that the length of linkers had apparent influence on anti cell adhesion activity.
