The Synthesis Of Fused Heterocyclic Azasugar Analogs

Azasugars(Iminosugars)has aroused great interests in recent decades due to their enormous therapeutic potential in many diseases such as diabetes,viral infection and lysosomal storage disorders.Azasugars are sugars in which the endocyclic oxygen is substituded with nitrogen atom.Most representative natural azasugars are penta/hexacyclic amine glycoalkaloids.This article summarizes the development of tri/tetracyclic condensed hetero-azasugar compounds in recent years.Based on our previous work,in this paper,novel fused tricyclic azasugars,and tetracyclic azasugar fused thiazine oxazolidinone derivatives were designed.According to the literature method,the reaction was performed under microwave irridation using xylose and 1,2-diaminobenzene as starting material.Although the fused tricyclic heteroazasugars were not obtained,the open-chain glycoside modified by benzimidazole intermediates has been synthesized.After dehydration in Mitsunobu reaction,C-glycosides bearing benze fused imidazole were prepared,which might provide a potential protocol for the synthesis of C-glycosides.Compared with general methods,the method use unprotected sugar as material,and the procedure is simple and efficient by microwave.However,the current yield is low,the reaction conditions need to be further optimized.Using D-ribose as starting material.the intermediate k9,an azasugar containing azido group,was prepared through eight steps.The synthesis of tetracyclic azasugar fused thiazine oxazolidinone derivatives would be carried out by one-pot intramolecular Staudinger/azaWittig/cyclization after the primary hydroxyl in k9 was oxided to the corresponding aldehyde group.