Glucono-l,4-lactone

It has been reported by Coleby that, when solutions of n-glucono-l, 4-lactone, D-gulono-1,4-lactone, L-galactono-1,4-lactone and L-gulono-1,4-lactone are irradiated with x-rays (210kVp, 10mA), 7-rays (Co ), and fast electrons (4 Mev) under vacuum, the lactones are converted into the corresponding ascorbic acids. 

The isolation of tetra-O-methyl-n-glucono-l,4-lactone (8) from a hydrolyzate of the octa-O-methyllactobionic acid (7 R = Me). ... 

A fundamental aspect of irradiated, aqueous systems is indirect action over a range of concentrations of solute. Fenton reagent provides free radicals, and it might be expected that, within certain limits, yields of products would be independent of the concentration of carbohydrate. However, for a fixed amount of iron (II) sulfate and hydrogen peroxide, yields of carbon dioxide from D-glucono-1,4-lactone indicate otherwise. In part, this result must be attributed to competition of radicals, and it is to be expected that, as the initial n-glucono-l, 4-lactone] [Fe 3 ratio is increased, reactions (19), (22), and (23) will become less important. 

The imidazole ring can be introduced by the addition of 2-lithiol-[(dimethylamino)methyl]-lH-imidazole to 2,3,4,6-0-benzyl-glucono-l,4-lactone to give 42 [77] the reduction of which gave 43 and 44. Mesylation of the latter followed by NaH/DMF gave 45 in 38% yield. Regioselective aroylation of 43 and 44 followed by NaH/DMF gave a mixture of anomers 46 and 47 (80%) presumably via an elimination-addition mechanism (Fig. 8). 

Lactone, di-Ac 3,5-Di-0-acetyl-2,6-dibromo-2,6-dideoxy-D-glucono-l, 4-lactone... 

Bromo-3,6-dideoxyaltrose, B-106 2-Bromo-2,6-dideoxygluconoic acid, B-107 2-Bromo-2,6-dideoxy-L-glucono-l,4-lactone, B-107... 

Anhydro-D-glucono-l,4-lactone (17) is formed from D-glucono-1,5-lactone by treatment with formic acid in anhydrous HF, and D-mannono-1,4-lactone gives the C-2 epimer of (17) under the same conditions.2,3-Epoxyaldonolactones, as a mixture of 1,4- and 1,5- isomers, can be formed as indicated in Scheme 5 these can be used as precursors for 2-deoxy-2-fluoro-aldonolactones.16 A reference to a derivative of 2-chloro-2-deoxymannonic acid is given in Chapter 11. 

H And C n.m.r. methods have been used to determine the preferred conformations of the four D-pentono-1,A lactones and D-glucono-, D-mannono-, D-gulono- and D-galactono-1, -lactone. The kinetics of hydrolysis of D-glucono-l, 4-lactone have been examined in detail, and calcium D-arabinonate has been shown to epimerize to a mixture containing 8o of the D-ribo-lsomer at 137°C in the presence of calcium hydroxide. 

Addition of labelled potassium cyanide to 4-azido-2,5-di-0-benzyl-4-deoxy-D-arabinose followed by treatment with aqueous sodium bicarbonate gave (l- C)-5-azido-3,6-di-0-benzyl-D-glucono-l,4-lactone plus the mannono lactone. Subsequent reduction of the former with sodium borohydride then hydrogeno-lysis gave (l- C)-l-deoxynojirimycin. ... 

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