THE ALLYL GROUP FOR PROTECTION IN CARBOHYDRATE-CHEMISTRY .27. THE PREPARATION OF PHOSPHORYLATED INTERMEDIATES FOR THE SYNTHESIS OF RACEMIC AND CHIRAL MYOINOSITOL 1,4,5-TRISPHOSPHATE AND ITS PHOSPHOROTHIOATE ANALOGS

Reaction of racemic 1,2,4-tri-O-benzyl-myo-inositol 3-[di-(2,2,2-trichloroethyl) phosphate] with bis(2,2,2-trichloroethyl) phosphorochloridate gave a mixture of the 3,5- and 3,6-bisphosphate derivatives which were difficult to separate and could not be phosphorylated further. The bisphosphates were synthesised by the phosphorylation of the 5- and 6-0-(cis-prop-1-enyl) derivatives of racemic 1,2,4-tri-O-benzyl-myo-inositol [prepared from 1,2,4-tri-O-benzyl-3,5- and -3,6-di-O-(cis-prop-1-enyl)-myo-inositol, respectively] and subsequent acidic hydrolysis. 1D-2,3,6-Tri-O-benzyl-1,4-di-O-(cis-prop-1-enyl)-myo-inositol was converted into crystalline 1D-2,3,6-tri-O-benzyl-myo-inositol 1,4-bis(dibenzyl phosphate), and thence into the crystalline 1,4,5-tris(dibenzyl phosphate) which was also obtained, using dibenzyloxy(diisopropylamino)phosphine, from ID-2,3,6-tri-O-benzyl-myo-inositol. The latter compound was converted, using bis(2-cyanoethoxy)(diisopropylamino)phosphine, into the crystalline 1,4,5-tris[di(2-cyanoethyl)phosphate] which was also obtained from the 4,5-bis[di-(2-cyanoethyl)phosphate]. Both the tris[di-(2-cyanoethyl)phosphate] and the tris(dibenzyl phosphate) are intermediates suitable for the synthesis of 1,4,5-IP3.