Regiocontrolled acylation of myo-inositol orthoformate

Iron (III) chelation and antioxidant properties of myo-inositol phosphorylated polymeric microspheres

New chelating and antioxidant polymeric microspheres were synthesized through precipitation polymerization of 4-O-(4-vinylbenzyl)-myo-inositol 1,3,5-orthoformate with ethylene glycol dimethacrylate and subsequent exhaustive phosphorylation of the myo-inositol groups with phosphoric acid. Three different microspheres using different molar ratios of the two co-monomers were prepared. The antioxidant properties of these polymers were evaluated in rat liver microsomal membranes. This study showed that the macromolecular systems are very effective at inhibiting iron-dependent lipid peroxidation of the membranes. This antioxidant effect is due to the chelating properties of polyphosphorylated inositol residues in the polymeric devices toward ferric ions. The amount of polyphosphorylated inositol in the microspheres was found to play a crucial role in determining the chelating efficiency of the polymers: the polymer with the greatest amount of polyphosphorylated inositol was the most powerful antioxidant polymer.

Sulfonate protecting groups. Regioselective sulfonylation of myo-inositol orthoesters-improved synthesis of precursors of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,5,6-pentakisphosphate and related derivatives

The regioselectivity of sulfonylation of myo-inositol orthoesters was controlled by the use of different bases to obtain the desired sulfonate. Monosulfonylation of myo-inositol orthoesters in the presence of one equivalent of sodium hydride or triethylamine resulted in the sulfonylation of the 4-hydroxyl group. The use of pyridine as a base for the same reaction resulted in sulfonylation of the 2-hydroxyl group. Disulfonylation of these orthoesters in the presence of excess sodium hydride yielded the 4,6-di-O-sulfonylated orthoesters. However, the use of triethylamine or pyridine instead of sodium hydride yielded the 2,4-di-O-sulfonylated orthoester. Sulfonylated derivatives of myo-inositol orthoesters were stable to conditions of O-alkylation but were cleaved using magnesium/methanol or sodium methoxide in methanol to regenerate the corresponding myo-inositol orthoester derivative. These new methods of protection-deprotection have been used: (i) for the efficient synthesis of enantiomers of 2,4-di-O-benzyl-myo-inositol, which are precursors for the synthesis of D- and L-myo-inositol 1,3,4,5-tetrakisphosphate; (ii) for the preparation of 2-O-benzyl-myo-inositol which is a precursor for the preparation of myo-inositol 1,3,4,5,6-pentakisphosphate.