Synthesis of Carbohydrate esters and selective anomeric deacetylation by MgO/MeOH
Suitably protected 1 -hydroxy sugars, especially the acetylated 1 -hydroxy sugars, are valuable building blocks for the construction of various glycosyl donors, which are widely used for glycosylation reactions in carbohydrate chemistry. In this project some carbohydrates acetylated and benzoylated. Anomeric configuration deacetylated by MgO/MeOH as a catalyst. Synthesized compounds identified by mean of FT IR, 1H and 13C NMR spectroscopy techniques.
The acetyl ester plays an important role for protection of the hydroxyl group in organic synthesis. Consequently, numerous methodologies have so far been put forth for the acetylation of alcohols. In striking contrast, the deprotection of the acetyl esters is much less studied despite its practical significance in synthetic processes. It should be carried out under mild conditions to suppress racemization as well as decomposition of coexisting functions. Alkaline hydrolysis is most commonly employed, yet a number of functional groups are not tolerated in this procedure. Transesterification serves considerably well to this end.(1) Hydroxy groups in carbohydrates esterified easily. Acetylation is the most commonreaction for esterification. Selective anomericdeacetylation is often a key step in oligosaccharide synthesis commonly used for the preparation of anomerictrichloroacetimidates, glycosyl fluorides and glycosyl iodides, which are widely used in glycosylation reactions in carbohydrate chemistry. Acetylated -1-hydroxy carbohydrates have valuable structures for diverse reactions of glycosides. Selective anomeric deacetylation is often a key step in o ...