Glucitol hydrolysis

A somewhat similar configurational correlation between (leva)-glyceraldehyde and (dexfro)-lactic acid has been made by Wolfrom, Lemieux, Olin and Weisblat.36 Reductive desulfurization of tetra-acetyl-2-methyl-D-glucose diethyl thioacetal (XXVII) and hydrolysis of the product gave 2-methyl-l-desoxy-D-glucitol (XXVIII) oxidation... 

Both L-gulose12,13 (9) and D-gulose (d-9, see Ref. 10) have been oxidized with bromine to L- or D-gulonic acid, respectively (see Scheme 1). L-Gulose (9) has been prepared by a number of different procedures. Schemes 2 and 3 show two early procedures that afforded L-gu-lose, but the overall yields were low (<30%). In the first procedure12 (see Scheme 2), D-glucitol (10) was converted into 2,4-O-benzylidene-D-glucitol (11), which was then oxidized with lead tetraacetate to 2,4-O-benzylidene-L-xylose (12). Nitromethane was added to 12 to afford crystalline 13 in 50% yield. Hydrolysis of 13 provided 14, which was treated with sodium hydroxide, followed by sulfuric acid, to afford 9, which was isolated in 52% yield as the 2-benzyl-2-phenylhydrazone. 

In the second procedure13 (see Scheme 3), D-glucitol (10) was converted into 5-O-benzoyl-1,3 2,4-di-O-ethyl idene-6-O-trityl-D-glucitol (17) by successive treatment with acetaldehyde to produce 15, with chlorotriphenylmethane to provide 16, and with benzoyl chloride to afford 17. Selective removal of the trityl protecting group from 17, to give 18, followed by oxidation of 18, provided 19 which, on hydrolysis, afforded L-gulose (9). 

Lemer (29) reported a simple synthesis of L-erythrose that involves 2,3-di-O-isopropylidene-D-gulono-1,4-lactone (7b) as a key intermediate. Reduction of the lactone group of 7b with sodium borohydride, followed by periodate oxidation of the L-glucitol derivative, afforded 2,3-O-isopropy-lidene-L-erythrose. The free sugar may be readily obtained by acidic hydrolysis of the latter. 

Certain synthetic heptitols that could not be separated by paper chromatography or by electrophoresis have been separated as their O-trimethylsilyl derivatives.404 The procedure of reductive, alkaline hydrolysis, much used in glycopeptide research, yields alditols that have been estimated as their trimethylsilyl ethers,59,405 and D-glucitol in mammalian nerve has similarly been determined.406... 

Oxepane (seven-membered) rings (1,6-anhydrohexitols)52 have been prepared from the 3,4-isopropylidene acetals of D-mannitol, D-glucitol, and L-iditol, by way of alkaline hydrolysis of the corresponding 1,2 5,6-dianhydrides. The ring structures of the products were established through periodate oxidation and lead tetraacetate oxidation the requisite amount of formic acid was produced, and 3 equivalents of lead tetraacetate were consumed. No inversions at any of the asymmetric centers were involved in the reactions conducted, so the oxepanes had retained the configurations of the starting hexitols. 

Periodate oxidation of 2-acetamido-1,2-dideoxy-3,4-0-isopropylidene-D-glucitol (33) affords 4-acetamido-4,5-dideoxy-2,3-0-isopropylidene-aldehydo-c-xylose, which, on hydrolysis with acetic acid, gives31 the pyrrolidine 34. The same series of reactions was performed31" on the... 

Several miscellaneous procedures have been reported for the preparation of L-gulonic acid (47). 5-0-Benzoyl-l,3 2,4-di-0-ethylidene-D-glucitol (72) was oxidized388 with chromium trioxide to 73. After hydrolysis of 73, the L-gulose (45) formed was oxidized369,370 with bromine to 21. As noted in Section III,5b, 3,5 4,6-di-0-ethylidene-L-gu-lonic acid (50) was prepared from 3,5 4,6-di-0-ethylidene-D-gulitol (49) in 50-70% yield. By hydrolysis, 50 afforded333 21. 

However, when acidic zeolites are used as supports in the hydrogenation of aqueous solutions of disaccharides, such as sucrose, and polysaccharides, such as starch, a cooperative hydrolysis effect is observed.156 The simultaneous hydrolysis of sucrose and hydrogenation of the two liberated monosaccharides, i.e. glucose and fructose, leads to a mixture of glucitol and mannitol in the expected ratio 3 1. For starch, consisting only of glucose units, sorbitol is the major product obtained after simultaneous hydrolysis and hydrogenation. 

A synthesis of L-sorbose by the diazomethane reaction on 2,4 3,5-diethylidene-L-xylonyl chloride (XXX) was performed by Gatzi and Reichstein.54 Oxidation of 3,5 4,6-diethylidene-L-gulitol (l,3 2,4-dieth-ylidene-D-glucitol) (XXVIII) gave the diethylidene-L-xylonic acid (XXIX). Addition of diazomethane to the acid chloride (XXX) yielded a sirupy diazoketone (XXXI) from which L-sorbose (XXXII) was obtained by acid hydrolysis with dilute sulfuric acid. 

L-Sorbose (XXXII) itself was prepared by hydrolysis of 1-benzoyl-L-sorbose (XXXV) which had been prepared by monobenzoylation (at carbon atom 6) of diethylidene-D-glucitol, followed by similar oxidation (see also p. 127). 

O-0-D-Glucopyranosyl-L-gulonic acid [82] hydrolyses more than 100 times faster than 4-0-/3-D-glucopyranosyl-D-glucitol [83] at pH 4 and exhibits a plateau in its pH-rate profile (Smidsrod et al., 1966), although a complete profile was not obtained. Intramolecular catalysis [84] was proposed and likewise for hydrolysis of alginate... 

In another reaction sequence, compound 193 was prepared by periodate cleavage of 2-deoxy-2-(2,4-dinitroanilino)-3,4-0-isopropyli-dene-D-glucitol or 2-amino-2-deoxy-3,4-0-isopropylidene-D-glu-citol 1,2-carbamate (see Section II, 5 p. 147). Hydrolysis of the 4-acetamido-4-deoxy-1,2-0-isopropylidene-L-xylopyranose resulting (several steps), or of the N-acetyl derivative formed on treatment of 4-amino-4-deoxy-l,2-0-isopropylidene-L-xylopyranose with acetic anhydride in water, leads to the crystalline pyranose form 193. It is noteworthy that free 4-amino-4-deoxy-L-xylose, which, in alkaline solution, consists of the equilibrium mixture 101a 103a (see... 

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