D-Glucurono-6,3-lactone

On reaction with hydroxylamine in the presence of appropriate bases, such derivatives of D-glucofuranurono-6,3-lactones as 25, 26, and 33 form114 N-hydroxyamides. On the other hand, when treated with hydroxylamine without base catalysis, compound 4 yields115 aWeJjt/do-D-glucurono-6,3-lactone oxime. 

Catalytic hydrogenation of the oxime of D-glucurono-6,3-lactone leads179 to simultaneous isomerization with formation of L-gulono-... 

Y. Watanabe, M. Milani, and S. Ozaki, Synthesis of optically active inositol derivatives starting from D-glucurono-6,3-lactone, Chem. Lett. 123 (1987). 

The ready formation of furanosides from D-glucurono-6,3-lactone is aided by the presence of the lactone ring. 

Cellulose may also serve as the starting material for the preparation of D-glucurono-6,3-lactone. However, the methanolysis of cellulose to methyl a,/3-D-glucopyranoside (66) has thus far been reported to proceed in only low yield. Whereas the oxidation of cellulose to cell-uronic acid (65) proceeds in high yield,344 the hydrolysis of this material to 63 has not yet been efficiently achieved. The preparation of 63 has been reviewed in detail,345-349 as have its subsequent reactions.350... 

A formal synthesis of L-[6-3H]ascorbic acid was achieved when D-glucurono-6,3-lactone was reduced to L-[6-3H]gulono-l,4-lactone with sodium borotritide.354 L-Gulono-1,4-lactone has been converted into 1 by several routes (see Section III,7b,c). Starting with methyl o-xylo-2-hexulosonate, and following the method shown in Scheme 17, L-(5-2H)ascorbic acid was prepared by reduction of 121 with sodium boro-deuteride.547,548,587 In a related, but shorter, synthesis, sodium D-threo-2,5-hexodiulosonate was reduced with sodium borodeuteride to a mixture of keto-acids (see Section III,9d), which was esterified. By fractional recrystallization, methyl L-xylo-2-hexulosonate was obtained, and this was then converted598 into (5- H)l. 

The reducing group in uronic acids can be oxidized by nitric acid or bromine to yield aldaric acids. Uronic acids, as salts, can be quantitatively reduced to aldonic acids by borohydride.239 Lactones are readily reduced, as in the controlled conversion of D-glucurono-6,3-lactone into D-gluco-hexodialdose. The carboxyl group of glucuronic acids may be reduced to a primary alcoholic group. 

Base-catalyzed esterification of D-glucurono-6,3-lactone proceeds smoothly at room temperature.242 The acetylated glycuronic acids, and the per-O-acetylglycosyluronic halides of their methyl esters, are important precursors for the synthesis of glycosiduronic acids. D-Glucofuranurono-6,3-lactone... 

Standard D-Glucurono-6,3-lactone This chemical (C6H8Ofi) is available as a reference standard with an assay of 100.0 1.0% (24.99 0.25% C02) from Aldrich Chemical Co. 

System Suitability Test Transfer about 250.0 mg of Standard D-Glucurono-6,3-lactone, accurately weighed, into the reaction flask, D, and carry out the Procedure described below. The system is considered suitable when the net titration results in a calculation of %C02 in a range of 24.73 to 25.26, which is equivalent to a range of 98.95 to 101.06% D-Glucur-ono-6,3-lactone. 

A surprising fragmentation reaction was encountered in attempts to prepare 5-deoxy-5-hydrazinohexuronic acids. Treatment of 1,2-0-cyclohexylidene - 5 - O - (methylsulfonyl) - a - D-glucurono-6,3-lactone... 

In a similar manner, methyl a-D-glucopyranoside (8, R = Me) can be oxidized catalytically in 87% yield to methyl a-D-glucopyranosiduronic acid (9, R = Me). This, however, is only converted to D-glucuronic acid in low yield, because of the necessarily severe conditions of acid hydrolysis. The total yield of n-glucurono-6,3-lactone amounts to 16%. A yield of 68% is obtained from the oxidation of methyl d-D-glucopyranoside. After hydrolysis with formic acid, D-glucurono-6,3-lactone is obtained in an over-all yield of 15%. 

The first synthesis, that of eri/fftro-tetrodialdose, was made by Wohl and Mylo, starting from acetylene. The basis of the method employed (both here and in the further syntheses of this dialdose) is the hydroxylation of malealdehyde or a derivative of the latter. The next method introduced was Uenzelmann s application of catalytic reduction by the Rosenmund procedure to tetra-O-acetylmucyl dichloride he thus obtained the corresponding tetraacetate of gaZacto-hexodialdose. By this procedure, the only known heptodialdose has also been prepared. Another reduction procedure, controlled reduction of D-glucurono-6,3-lactone with borohydride or sodium amalgam, was used by MacDonald and H. O. L. Fischer and by F. G. Fischer and Schmidt. ... 

There is some evidence that a small, perhaps variable, fraction of the acid side-chains in softwood xylans lacks the 4-0-methyl group. Roudier, in his extensive investigations on the uronic acids present in maritime pine, " isolated and identified 2-0(-a-D-glucopyranosyluronic acid)-D-xylose after partial hydrolysis of the wood. Hydrolysis of the xylan gave a small proportion of the same aldobiouronic acid. As previously mentioned (see Part I, p. 273), D-glucurono-6,3-lactone has been isolated from the wood of black spruce. " It has become evident that, despite the mild conditions often used, demethylation of the 4-0-methyl-D-glu-curonic acid residues may occur during hydrolysis of the above xylans. The presence or absence of D-glucuronic acid side-chains in hardwood or softwood xylans has, therefore, yet to be ascertained. 

The functionalities of the six carbon atoms in D-glucurono-6,3-lactone 294, which is commercially available, are properly protected except for the two hydroxyls at C-2 and -5. Epimerization at the C-5 carbon atom and cyclization between the terminal C-l and C-6 carbons will lead the carbocycle with the myo-configuration.Thus, 294 was... 

The polarographic behavior of D-glucurono-6,3-lactone " and d-mannurono-6,3-lactone was also studied, in order to develop analytical methods for their detection. The polarographic waves of these lactones appear only in unbuffered media, among which, 0.2 M aqueous lithium chloride solution proved to be the best base electrolyte, with 0.005%... 

P. Florio, R. J. Thomson, and M. von Itzstein, Rapid access to uronic-based mimetics of KDN2en from D-glucurono-6,3-lactone, Carbohydr. Res., 328 (2000) 445-448. 

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