Applicability of aluminum amalgam to the reduction of arylnitro groups

Design, synthesis and evaluation of tetrahydrocarbazole derivatives as potential hypoglycemic agents

Two series of tetrahydrocarbazole derivatives have been designed and synthesized based on ZG02, a promising candidate developed in our previous studies. The newly prepared compounds were screened for glucose consumption activity in HepG2 cell lines. Aza-tetrahydrocarbazole compound 12b showed the most potent hypoglycemic activity with a 45% increase in glucose consumption when compared to the solvent control, which had approximately 1.2-fold higher activity than the positive control compounds (metformin and ZG02). An investigation of the potential mechanism indicated that 12b may exhibit hypoglycemic activity via activation of the AMPK pathway. Metabolic stability assays revealed that 12b showed good stability profiles in both artificial gastrointestinal fluids and blood plasma from SD rats. An oral glucose tolerance test (OGTT) was performed and the results further confirmed that 12b was a potent hypoglycemic agent.

Chemoenzymatic route to stereodefined 2-(azidophenyl)oxazolines for click chemistry

Aryl-substituted esters of a racemic diprotected 2-azido-1-alkanol were submitted to the Staudinger/aza-Wittig reaction in order to assess scope and establish conditions for their cyclization to the corresponding 2,4,5-trisubstituted oxazolines. Following the cyclization study, the (2R,3R)-antipode of the azidoalkanol was obtained in high ee by incubation of the corresponding racemic azidoacetate with pig liver esterase (PLE). The p-nitrobenzoate of the enantioenriched 2-azido-1-alcohol was cyclized by the Staudinger/aza-Wittig to give the corresponding (4R,5R)-disubstituted-2-(4-nitrophenyl) oxazoline. Selective reduction of the nitrophenyloxazoline to the corresponding aminophenyloxazoline using aluminum amalgam followed by direct azidation of the 2-(4-aminophenyl) moiety provided the corresponding (4R,5R)-2-(4-azidophenyl) oxazoline derivative. The azidophenyl oxazoline was reacted with a proven click partner 4-ethynylfluorobenzene under copper/sodium ascorbate mediation to provide the click triazole product in high yield.