Alditols anhydroalditols

Reference has already been made to the formation of anhydro sugars under the influence of acid (see Section XI, p. 87). In a similar manner, alditols may be converted into anhydroalditols, and these may be difficult to distinguish from other polyhydric compounds of low molecular weight. Such a problem arises in the hydrolyzates of cell walls, where ribitol and glycerol are present. It has been shown, however, by Gregory that glycerol and an anhydroribitol may be separated readily as their trimethylsilyl ethers.401... 

The key sequence in the determination of the structures of 2,5-anhydro-D-mannose (2) and -D-talose (4) was their reduction to the corresponding 2,5-anhydroalditols (5 and 6) and identification of the asymmetric dialdehyde (7) resulting from oxidation of the anhydro-alditols with periodate.37,43... 

Anhydroalditol compounds of a rather unusual type are the C-glycosyl compounds (erroneously called C-glycosides ). As pointed out by Treibs,33 these are not glycosides, but they are anhydro-alditols.3 A variety of approaches has been employed for synthesis of... 

Full details on the preparation of urethane derivatives of 3,4-di-O-benzyl-l,2,5,6-tetradeoxy-l,2 5,6-diimino-L-iditol from D-mannitol as well as the 3,4-dideoxy-L- Areo compounds 24 (R = C02 Bu or COiBn), from a hex-3-enitol, have been reported. (See Vol. 28, p. 230, ref. 66 for an earlier report). In both cases l,6-diamino-l,6-dideoxy-2,5-anhydroalditols were minor by-products. V-Boc-L-/V/o-l,2 5,6-bis-aziridino derivatives have proved to be versatile intermediates for the preparation of imino-alditols. For example, treatment of the 3,4-di-O-benzyl compound with diethylaluminium cyanide affords a 1 2 mixture of pyrrolidine 25 piperidine 26, and with dilithium tetrabromonickelate (Li2NiBr4) gives bromo-derivative 27 from which displacement of bromide allows further functionalization. ... 

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