Thesis (M.Sc.)--Chulalongkorn University, 2008

An efficient synthesis of diastereomerically pure 5S- and 5R-amino-1,2,3,4-cyclohexanetetrols and quercitol derivatives from naturally available (+)-proto-quercitol was investigated. Proper stereochemistry of (+)-proto-quercitol perfectly set up for regioselective protection of hydroxyl group which was further functionalized into the target aminoquercitols in a straightforward manner. The present approach provided a protocol for preparing aminoquercitol in a large quantity. In addition, the absolute stereochemistry of (+)-proto-quercitol was first addressed using modified Mosher’s method. All the synthesized compounds including (+)-proto-quercitol were tested for α-glucosidase inhibitory activity by colorimetric method. Of synthesized aminocyclitols, 5R-amino-1,2,3,4-cyclohexanetetrol potentially inhibited α-glucosidase with IC₅₀ value of 12.5 µM, which was 45 times greater than that of standard antidiabetes drug acarbose.