Synthesis of tricyclic benzimidazole-iminosugars as potential glycosidase inhibitors via a Mitsunobu reaction.

A series of tricyclic benzimidazole-iminosugars 1(a-f) and 2(a-f) were synthesized and evaluated for their their inhibitory activities against five glycosidases. The synthesis initiated from the benzyl protected sugar (aldehyde) 5 that reacted with 1,2-diaminobenzene to afford aldo-benzimidazole 6 by the iodine-induced oxidative condensation. Then, tricyclic compound 7 was obtained in high yields of 73%-87% by the key Mitsunobu reaction through intramolecular cyclization of the unprotected OH and the NH in 6.

Synthesis of pentacyclic iminosugars with constrained butterfly-like conformation and their HIV-RT inhibitory activity.

Novel pentacyclic iminosugars 1 and 2 with the constrained butterfly-like conformation were first synthesized by the key intramolecular click reaction from the tricyclic iminosugars fused benzo[e][1,3]thiazin-4-one 3 and 4. The pentacyclic iminosugar was constructed by fusing both benzo[e][1,3]thiazin-4-one and triazolo[5,1-c][1,4]oxazepine scaffolds. Their structures were determined by their H, C NMR, and HRMS (ESI) spectra and X-ray.