Mwco-Inositol

Other quercitols have been synthesized by catalytic hydrogenolysis of the corresponding inososes (see p. 180). All the known quercitols are shown, with their names, in formulas CXXXIX-CXLIV according to Angyal and Macdonald s proposals,6 the quercitol of acorn is called (+)-profo-quercitol, and natural viburnitol is named (—)-w 6o-quercitol the corresponding Fletcher-Anderson-Lardy names are (+)-1 -deoxy-mwco-inositol and ( —)-1-deoxy-WM/o-inositol. Synthesis of the four as-yet-unknown diastereomers should not present serious difficulties. 

There are nine various inositols or cyclohexane-1,2,3,4,5,6-hexaols, including one pair of isomers. The myo-inositol is the most widespread isomer of inositol and, excluding alio-, cis-, epi- and mwco-inositol, all other inositols are of natural occurrence. 

The high proportion of muco-inositol formed in the isomerization is surprising. The isomerization of mj/o-inositol with acetic acid-sulturic acid (see Section VI, p. 190) gives an equilibrium mixture of myo-, DL-chtro-, and mwco-inositol in the ratios of 54 41 5. These ratios correspond to the relative thermodynamic stabilities of the three inositols as determined on the basis of intramolecular, steric interactions of the substituents, whereas the isomerization in hydrogen fluoride gives the thermodynamically least-stable isomer (muco) in the highest yield. This discrepancy can be rationalized if it is postulated that the acetoxonium ion in the mwco-inositol system is further stabilized as a di-cation of structure 138, formed because... 

A crystal structural analysis of mwco-inositol is referred to in Chapter 21. iV-(2-chloroethyl)-iV-nitrosoureido derivatives of cyclopentane- and cyclohexane-tetrols are mentioned in Chapter 18. Unsaturated glycosylated cyclitol derivatives are referred to in Chapter 12. 

An easy conversion of naturally occurring quebrachitol (2-0-methyl-L-c/u>o-inositol) to mwco-inositol has been described, involving oxidative removal of the methyl group from the perbenzoyl derivative and inversion at C-2 by solvolysis of the corresponding tosylate with concomitant benzoate neighbouring-group participation. ... 

Di-0-isopropylidene-l,4-di-0-methyl-D-c/iiro-inositol, 1-28 l,2 5,6-Di-0-isopropylidene-3,4-di-0-tosyl-L-cA/ra-inositol, 1-28 l,2 5,6-Di-0-isopropylidene-L-cAi>o-inositol, 1-28 l,2 4,5-Di-0 -isopropylidene-mwco -inositol, 1-31 l,2 3,4-Di-0-isopropylidene-myo-inositol, 1-32 l,2 4,5-Di-0-isopropylidene-myo-inositol, 1-32 l,2 5,6-Di-0-isopropylidene-myo-inositol, 1-32 1,2 5,6-Di- O -isopropylidene-3- O -methyl-D-c/iiro -inositol, 1-28... 

Inositol L-form 1,2,3,5-Tetra-O-angeloyl, 1-28 -Inositol L-form 1,2,4,5-Tetra-O-angeloyl, 1-28 -Inositol l,2 3,4-Di-0-cyclohexylidene, 5-benzoyl, 1-30 wyo-Inositol 1,4-Diphosphate, 1-32 wyo-Inositol 1-0-p-D-Glucopyranoside, nona-Me, 1-32 wyo-Inositol hexakis(phosphate), 1-32 wyo-Inositol monoorthoformate, 1-32 wyo-Inositol 1,2,3,4,5-Pentaphosphate, 1-32 wyo-Inositol 1,2,3,4,6-Pentaphosphate, 1-32 myo-Inositol 1,2,3,5,6-Pentaphosphate, 1-32 myo-Inositol 1,2,4,5,6-Pentaphosphate, 1-32 myo-Inositol 1,3,4,5,6-Pentaphosphate, 1-32 myo-Inositol 2,3,4,5,6-Pentaphosphate, 1-32 myo-Inositol 1-Phosphate, ( ), 1-32 myo-Inositol 4-Phosphate, ( ), 1-32 myo-Inositol 1-Phosphate, 1-32 myo-Inositol 2-Phosphate, 1-32 myo-Inositol 3-Phosphate, 1-32 myo-Inositol 4-Phosphate, 1-32 myo-Inositol 5-Phosphate, 1-32 myo-Inositol 6-Phosphate, 1-32 myo-Inositol 3,4,5,6-Tetra-Ac, 1-32 myo-Inositol 2,3,5,6-Tetrabenzyl, 1-32 myo-Inositol 1,3,4,5-Tetraphosphate, 1-32 myo-Inositol 1,3,5,6-Tetraphosphate, 1-32 myo-Inositol 1,4,5,6-Tetraphosphate, 1-32 myo-Inositol 3,4,5,6-Tetraphosphate, 1-32 myo-Inositol 2,4,6-TVibenzyl, 1,3,5-0-methylidyne, 1-32 myo-Inositol 2,3,5-Tribenzyl, 1-32 myo-Inositol 1,2,3-Triphosphate, 1-32 myo-Inositol 1,3,4-Triphosphate, 1-32 myo-Inositol 1,4,5-Triphosphate, 1-32 myo-Inositol 1,4,6-Triphosphate, 1-32 myo-Inositol 2,4,5-Triphosphate, 1-32 myo -Inositol-1,2,6-triphosphate, 1-32 fl//o-Inositol, 1-27 i -Inositol, 1-28 /-Inositol, 1-28 cw-Inositol, 1-29 ep/-Inositol, 1-30 mwco-Inositol, 1-31... 

The diolization of the double bond in this series of reactions appears to be analogous to the diolization of the double bond of conduritol, a cyclohexene-tetrol (see Cyclitol section). When the hexenetetrol above was oxidized directly, the hydroxyls entered cis to the hydroxyls already present and allitol was the chief product similarly, aHo-inositol was obtained on oxidation of o-isopropylideneconduritol diacetate with potassium permanganate. On the other hand, for the two fully acetylated tetrols (acyclic and cyclic), the hydroxyls entered trans to those already present, giving galactitol and mwco-inositol tetraacetate, respectively (p. 284). 

All optically active derivatives are called d or l, based on the configuration of carbon 6. The configuration of carbon 6 is found by viewing the Fischer-type projection (p. 9) with carbons 5 and 1 away from the viewer and C-5 at the top. When an optically inactive cyclitol has been made asymmetric by substitution, the d or l is put at the beginning of the name, e.g., D-l-O-methyl-mwco-inositol, but 3-0-methyl-D-inositol. When an inositol derivative contains less than six asymmetric carbon atoms, it is named as a derivative of the related inositol that has the maximum number of CIS OH groups. If this leads to more than one possibility, the parent inositol is chosen that has the lowest possible number for its substituents CIS to the OH on carbon 1. 

The configuration of conduritol, and incidentally those of aZZo-inositol, mwco-inositol, and dihydroconduritol, was elucidated in 1939 by Dangschat and Fischer (6 ), who applied the acetonation-oxidation technique previously used so successfully on quinic and shikimic acids. The steps utilized were as follows ... 

The synthesis of deoxynitroinositols by the base-catalysed cyclization of 6-deoxy-3-0-methyl-6-nitro-D-allose (318) and -L-talose (319) has been investigated. The products shown in Scheme 113 were formed under conditions (pH 8—9) favouring kinetic control, whereas similar equilibrium mixtures of stereoisomers were obtained from (318) and (319) in strongly alkaline solutions (pH >12) that favour thermodynamic control. A related base-catalysed cyclization of 3-0-benzyl-6-deoxy-6-nitro-D-glucose and -L-idose gave mixtures of O-benzyldeoxynitroinositols. Under conditions of kinetic control, the D- / c<7-derivative furnished mainly 6-0-benzyl-3-deoxy-3-nitro-mwco-inositol... 

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