A concise synthesis of N-substituted fagomine derivatives and the systematic exploration of their α-glycosidase inhibition.

A novel and concise scheme has been developed successfully for the syntheses of N-substituted fagomine derivatives. The transformation of lactone (2) to 1,5-diol (3) was carried on with high yield (93-95%). The cyclization of 4 to 5 is a high stereoselective reaction (de value > 98%). It is disclosed that bulky substituent at N atom of the piperidine decreases the inhibition activity except those substituents having the ability of solvation or forming disulfide bond with M444 at the active site of α-glycosidase, which enhance the interaction with enzyme. Compounds with S-configuration at C-3 show greater activity than those with R-configuration. The structure-activity relationship study is also supported by molecular docking analysis.