The total synthesis of (±)-myo-inositol-1,3,4-trisphosphate, (±)-myo-inositol-2,4,5-trisphosphate and (±)-myo-inositol-1,3,4,5-tetrakisphosphate

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.

Synthesis of D- and L-myo-inositol 2,4,5-trisphosphate and trisphosphorothioate: structural analogues of D-myo-inositol 1,4,5-trisphosphate

The preparation of D- and L-myo-inositol 2,4,5-trisphosphate is described, together with the phosphorothioate counterparts. The known chiral diols D- and L-1,4-di-O-benzyl-5,6-bis-O-p-methoxybenzyl-myo-inositol were regioselectively protected at the 3-position using a benzyl group via a 2,3-O-stannylene acetal. Removal of the p-methoxybenzyl groups of each enantiomer gave D- and L-1,3,6-tri-O-benzyl-myo-inositol. Phosphitylation with bis(benzyloxy)diisoproplyaminophosphine and 1H-tetrazole gave the trisphosphite intermediate for each enantiomer. Oxidation with 3-chloroperoxybenzoic acid gave the fully protected D- and L-myo-inositol 2,4,5-trisphosphates. Sulphoxidation of the D- and L-2,4,5-trisphosphite intermediates gave the fully protected D- and L-myo-inositol 2,4,5-trisphosphorothioate compounds. The fully protected trisphosphates were deblocked using hydrogenolysis and the phosphorothioates were deprotected using sodium in liquid ammonia. The individual compounds were then purified using ion exchange chromatography to afford pure D- and L-myo-inositol 2,4,5-trisphosphates together with the corresponding phosphorothioates.

A membrane-permeant, bioactivatable derivative of Ins(1,3,4)P3 and its effect on Cl(-)-secretion from T84 cells

The synthesis of rac-2,5,6-tri-O-butyryl-myo-inositol 1,3,4-trisphosphate hexakis(acetoxymethyl) ester [Bt3-Ins(1,3,4)P3/AM, 1], a membrane-permeant derivative of myo-inositol 1,3,4-trisphosphate [Ins(1,3,4)P3] is reported. 1 inhibited calcium-mediated chloride secretion of T84 cells, suggesting a regulatory link of Ins(1,3,4)P3 and the biosynthesis of the known inhibitor myo-inositol 3,4,5,6-tetrakisphosphate.

Synthesis of phosphonate derivatives of myo-inositol for use in biochemical studies of inositol-binding proteins

Phospholipids containing the inositol headgroup (phosphoinositides) serve as membrane storage forms of a family of messenger molecules that transmit signals in cells. In this study a general synthesis of myo-inositol phosphate derivatives in which the phosphorus oxygen bond is replaced with a phosphorus carbon bond (i.e. phosphonates) is presented. Four specific examples of phosphonate analogs of phosphatidylinositol (PI) are prepared which have a single alkyl chain in place of the diacylglycerol. These derivatives are stable in neutral and alkaline solutions and are designed for use in biochemical studies of PI-specific phospholipases C and other enzymes involved in the phosphoinositide signal transduction pathway.