Mi/o-Inosose

Hydrogenation with hydrogen and a metallic catalyst has been used27 to convert mi/o-inosose-2 into mi/o-inositol-2-d, and to obtain methyl 2-deoxy-/3(and a)-D-glucopyranoside-2-d from methyl 2-deoxy-2-iodo-/3-D-glucopyranoside and from methyl 2-deoxy-2-iodo-a-D-mannopyranoside, respectively.28 The equatorially attached... 

D-glucose. This transformation has recently been demonstrated (32b), Synthesis in vitro is based on the work of Grosheintz and Fischer (S3). They found that 6-deoxy-6-nitro-D-glucose (or, likewise, 6-deoxy-6-nitro-L-idose) condensed in slightly alkaline solution to form two monodeoxymononitro-iiiositols. These were converted to the corresponding amines, one of which can also be obtained by reduction of the phenylhydrazone or oxime of mi/o-inosose-2 (scyllo-myo-inosose) h). The final and crucial step,... 

Mytilitol (C-methyl-scyllo-mositol) (66) (Fig. 1), m.p. 266-268°, is found in the muscle of Mytilus edvliSy a mussel (67) j and in a marine tunicate, Cionia intestinalis (68), The epimeric isomytilitol obtained synthetically through mi/o-inosose-2 (bioinosose) is 2-C-methyl-m2/o-inositol. Both pentaacetates and hexaacetates can be prepared from mytilitol presumably the tertiary hydroxyl resists acetylation. Postemak (66) has also succeeded in synthesizing hydroxymytilitol, m.p. 247°, and hydroxyiso-mytilitol, m.p. 233°, from m2/o-inosose-2 by means of the Amdt-Eistert synthesis. These are the first-known heptahydric homologs of an inositol. 

Optically active forms can also be oxidized. L-mi/o-Inosose (d-inosose) is obtained from D-inositol (93) (Fig. 1). Likewise, L-inositol is converted to d-... 

If two axial hydroxyl groups in a molecule are sterically equivalent, they are oxidized at the same rate. Thus, the oxidation of epi-inositol (32) gives racemic ( )-epf-inosose (33, 34), which is also obtained by the oxidation of mi/o-inositol (23) with nitric acid. As expected, neo-inositol (35) yields pure neo-inosose (36) on catalytic oxidation. Hydrogenation of the... 

The oxidation of inositols to inososes (cycloses) by Acetobacter suboxydans is of importance in the determination of configuration (e.g., Posternak s work on mi/o-inositol, p. 275) and in the interconversion of inositols by reduction of the inosose. Bertrand s rule (p. 133) accurately predicts the point of attack in the acyclic series, but the situation is more complex in the inositol series. The specificity of A, suboxydans appears to be related to the conformation of the cyclohexane ring of the inositols. Inositols, like other substituted cyclohexanes, may exist in boat or chair forms (86), (See Chapter I.) The chair form in which the distances between the hydroxyl groups is at a maximum appears to be the preferred conformation. Substituents that are oriented nearly parallel to the average plane of the puckered ring are called equatorial. They lie alternately above and below the plane. Substituents that are perpendicular are called axial (formerly, polar) (87), Conversion to the second chair form causes interchange of... 

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