Synthesis and properties of cyclo-α-1,4-manno-2,3-epoxides

Abstract

Treatment of per-2-O-tosyl-cyclodextrins with K₂CO₃ allows the synthesis of cyclomannoepoxides 2a, 2b, 2c in high yields (>90%). The glucopyranose structure of 2a, 2b, 2c, is assigned from the ¹H coupling pattern (J_1,2 = 0 Hz, J_2,3 = 3.5 Hz, J_3,4 = 0 Hz), as a half chair conformation. 2b shows surfactant properties in water. Full analysis of the NMR spectra of 2a, 2b, 2c has been carried out. The inclusion and hydrolytic properties of 2 differ from those of the parent cyclodextrins as a result of a lack of secondary hydroxyl groups capable of forming hydrogen-bonded dimers.