L,3-0- -D-mannitol

D,L-Mannitol has been obtained by sodium amalgam reduction of D,L-mannose. The identical hexitol is formed from the formaldehyde polymer, acrose, by conversion through its osazone and osone to D,L-fmctose (a-acrose) followed by reduction (83). 

Very little was published on the synthesis of hexitols from unsaturated intermediates between the time of Griner s work and 1933, when it occurred to me that it might be possible to add four hydroxyl groups to divinylglycol by means of a solution of silver chlorate containing a small amount of osmic acid. In carrying out this work I had the assistance of one of my students, Joseph Wiemann. We succeeded far beyond our expectations and obtained allitol, unknown up to that time, and d,l-mannitol. 

An amount of 16 g. of the glycol (m. p. 18°) dissolved in 250 ml. of water was oxidized with 18 g. of silver chlorate and 0.3 g. of osmic acid. The reaction mixture yielded 3 g. of allitol and no D,L-mannitol. We may therefore assign the meso configuration to the divinylglycol melting at 18°, since on hydroxylation it yielded allitol, but not D,L-mannitol. 

The mother liquor was then treated with a small amount of ether, whereupon it separated into two layers. The lower layer consisted of a black sirup, which, when treated with absolute alcohol very slowly deposited some crystals, 1 g., consisting largely of D,L-mannitol. The upper layer was treated with a large volume of ether, which caused the precipitation of a considerable quantity of a brown sirup. Crystallization began almost immediately, especially when the sirup was treated with absolute alcohol. The crystals were collected and there was obtained in this way 12 g. of crude allitol. After solution in water and precipitation with alcohol, the crystals melted at 140°, but still contained a small amount of impurity. After several recrystallizations they melted at 149°. 

Upon standing, the mother liquor deposited more allitol—some 3 g. after a period of two months. No crystalline material was obtained from the ethereal solution. We thus obtained from 100 g. of divinylglycol, 11 g. of D,L-mannitol and 15 g. of allitol. 

It is evident that syntheses of the Lespieau type can lead to a great number of polyhydroxy compounds. Wiemann has prepared compounds such as CHsCH2(CHOH)6CH2CH3, which he calls diethyl mannitol. It would seem better to designate this substance a tetra-desoxy decitol or decane hexol since its configuration is not known with certainty. Apparently this type of synthesis leads to symmetrical arrangements of hydroxyl groups, since allitol, dulcitol and D,L-mannitol are the only hexitols that were identified as products. 

Alditols, Cyclitols and Derivatives Thereof. - 2,5 3,4-Dianhydro-D-altritol, 2,5-aohydro-3,4-0-(l,2-ethanediyl)-D mannitol, pentaerythritol tetraacetate, ribitol tetraacetate, xylitol tetraacetate, D-arabinitol tetraacetate, D, L-arabinitol tetraacetate, 2,4 3,5-di-0-isopropylidene-D-mannitol, 2 hexa-O-acetyl-D-mannitol, allitol hexaacetate, D-mannitol hexaacetate, D, L-mannitol hexaacetate, D-iditol hexaacetate, D, L-iditol hexaacetate, D, L-glucitol hexaacetate, D, L-altritol hexaacetate, L-galacto-D-galacto-decitol (which is C2-symmetric), 5 6-0-benzyl-2,3-0-[(S)-caniphanylidene]-l,4,5-tris-0-pivaloyl-D-myo-inositol, 6D-3,6-di-0-benzyl-l-0-[(S)-camphanyl]-2-deoxy-2,2-difluoro-4,5-0-isopropylidene- y< -inositol, cyclopentane 28. ... 

---