Study Of Selective Deprotection Of Isopropylidene Aldoses

For the synthesis of sugars, the selective deprotection of protective group is one of the most extensively used protocols. In this thesis, methodologies of selective deprotection of hydroxyl isopropylidene acetals as protective group using two kinds of solid acidic catalysts are described. The research results are summarized below:In this paper, eight kinds of O-diisopropylidene monosaccharides were synthesized and applied as substrates in then deprotective reactions.A novel methodology for chemoselective deprotection using SO₄^2-/TiO₂ is described. It was found that primary isopropylidene was selectively deprotected in excellent yields using 1.0 equivalent SO₄^2-/TiO₂ as catalyst in MeOH-H2O (9:1) at room temperature. It's a mild, efficient and excellent chemoselective method for deprotection of acetonides.Isopropylidene acetals could also be efficiently selectively deprotected between 40 and 90 minutes using acidic ion-exchange resin as catalyst in MeOH-H2O (9:1) at room temperature to give corresponding products in good to excellent yields. This method has the advantages of high selectivity, short time and high yield (89%-96%).