Epimerization of Monosaccharides in Acetic Acid and Acetic Anhydride. Synthesis of D-Altrose

1972 ◽  
Vol 50 (7) ◽  
pp. 1092-1094 ◽  
Author(s):  
Walter Sowa
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Chromatographic Separation ◽  
Reaction Conditions

Acetolysis of 1,2;5,6-di-O-isopropylidene-α-D-allofuranose occurred with inversion at C-2 in a medium composed of acetic acid, acetic anhydride, and sulfuric acid. D-Altrose was isolated in 45% yield by deacetylation and chromatographic separation of the mixture of products. Unsubstituted D-allose did not epimerize under the same reaction conditions.

Epimerization of Monosaccharides Under Acetolysis Conditions

1971 ◽  
Vol 49 (20) ◽  
pp. 3292-3298 ◽  
Author(s):  
Walter Sowa
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
High Concentration

Monosaccharides with a cis-configuration at C-2 and -3 readily undergo inversion at C-2 in an acetolysis medium composed of acetic acid, acetic anhydride, and sulfuric acid. The acetolysis-inversion reaction has been carried out with 2,3;5,6-di-O-isopropylidene-D-gulofuranose, 2,3;6,7-di-O-isopropylidene-D-glycero-D-gulo-heptose, 2,3-O-isopropylidene-D-ribose, D-ribose, and D-mannose using chromatography for isolation of the deacetylated epimeric products. The reaction requires a medium with a high concentration of acetic acid (ca. 90%) and appears to take place only with furanose structures. Inversions observed with the unsubstituted pyranoses D-ribose and D-mannose probably occur because of tautomerization to furanose forms. The epimerization proceeds in the direction which yields a smaller number of cis-oriented groups at C-2, -3, and -4 of the furanose forms of monosaccharides.

Kinetic Equations and Error Analysis for the Cholesterol—Sulfuric Acid Reaction

1975 ◽  
Vol 21 (2) ◽  
pp. 199-205 ◽  
Author(s):  
Thomas E Hewitt ◽  
Harry L Pardue
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Error Analysis ◽  
Quantitative Data ◽  
Kinetic Equations ◽  
Experimental Conditions ◽  
Wide Range ◽  
Acid Reaction

Abstract Quantitative data reported in an earlier paper have been used to evaluate kinetic equations for the reaction of cholesterol with sulfuric acid in acetic acid—acetic anhydride medium. The equations satisfy experimental observations to within 6% over a wide range of experimental conditions. The equations have been used to justify mathematically the empirically developed measurement procedures described earlier and to predict the errors that can be expected for time and temperature uncertainties.

REACTIONS OF 2-ACETOXY-4,6-DI-O-ACETYL-3-O-(2,6-DICHLOROBENZOYL)-D-GLUCAL, TRI-O-ACETYL-3-DEOXY-α-D-erythro-HEX-2-ENOPYRANOSYL CHLORIDE, AND RELATED COMPOUNDS

1966 ◽  
Vol 44 (15) ◽  
pp. 1855-1862 ◽  
Author(s):  
R. U. Lemieux ◽  
R. J. Bose
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Potassium Acetate ◽  
Equimolar Mixture ◽  
Related Compounds ◽  
Reaction Compound

Attempts to dehydrobrominate tri-O-acetyl-3-O-tosyl-α-D-glucopyranosyl bromide with diethylamine led directly to products resulting from the replacement of the tosyloxy group by the diethylamine. It was readily possible to prepare 2-acetoxy-di-O-acetyl-3-(2,6-dichlorobenzoyl)-D-glucal (V). Acetolysis of this compound gave an equimolar mixture of the α- and β-anomers (II and VI, respectively) of 2-acetoxy-di-O-acetyl-pseudo-D-glucal as the first products of the reaction. Compound V reacted only reluctantly with methanol in pyridine to give a mixture of the anomeric methyl di-O-acetyl-3-deoxy-D-erythro-hex-2-enopyranosides. These glycosides were readily prepared by reaction of tri-O-acetyl-3-deoxy-α-D-erythro-hex-2-eno-pyranosyl chloride with methanol in the presence of pyridine. 2-Acetoxy-di-O-acetyl-3-O-mesitoyl-D-glucal was prepared from 3-O-mesitoyl-β-D-glucose. The anomerizations of compounds II and VI were examined with both sulfuric acid in 1:1 acetic acid – acetic anhydride and potassium acetate in acetic acid. The conformations of II and VI are discussed, as are a number of the mechanistic features of the reactions studied.

scholarly journals HISTOCHEMICAL ACYLATION OF ALDEHYDES PRODUCED BY PERIODIC ACID OXIDATION

1966 ◽  
Vol 14 (7) ◽  
pp. 529-537 ◽  
Author(s):  
R. D. LILLIE
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Glacial Acetic Acid ◽  
Periodic Acid ◽  
Potassium Hydroxide Solution ◽  
Acid Oxidation ◽  
Enol Acetate ◽  
Periodic Acid Oxidation ◽  
Schiff Reaction

Aldehydes produced in tissue sections by periodic acid oxidation are readily acetylated or benzoylated so as to weaken or completely prevent the Schiff and other chromogenic reactions. The reactivity of acylated aldehydes to Schiff reagent is promptly restored by saponification in alcoholic potassium hydroxide solution (10-20 min, 1% KOH, 70% ethanol). Benzoylation with 5-10% benzoyl chloride in pyridine gave the promptest, most complete and consistent aldehyde blockade, which was somewhat inferior on addition of 0.5% sulfuric acid. Pyridine acetic anhydride mixtures, 25, 40 and 50% gave partial to complete blockade. Addition of 0.25-0.5% sulfuric acid did not give consistent effects. Acetic anhydride at 60°C gave partial blockade at ½-5 hr, on addition of 0.01-0.25% sulfuric acid total or subtotal blockade was achieved. Acetylation in alcohol gave inferior resutlts. Use of 25% acetic anhydride ims glacial acetic acid gave inferior results; addition of 0.25% sulfuric acid produced total to subtotal blockade at 4-5 hr. Glacial acetic acid was without appreciable blockade effect. Sulfation in 10% and 25% H2SO4/glacial acetic acid failed to blockade aldehydes. Experiments with the peracetic acid Schiff reaction for ethylene groups indicate that some proportion of enol monobenzoate may be formed, and that with the various acetylation techniques a smaller or negligible proportion of enol acetate is formed. Acetic anhydride with 0.25% H2S04 at 60° appears to form only aldehyde diacetate. Experiments with the bromination silver techniques did not give satisfactory results.

An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Spectral Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Condensation Products ◽  
Unsaturated Lactones ◽  
C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

Development of a multi-sugar LC-MS/MS assay using simple chemical derivatization with acetic anhydride

2016 ◽  
Vol 8 (15) ◽  
pp. 3023-3033 ◽  
Author(s):  
Hermes Licea-Perez ◽  
Venkatraman Junnotula ◽  
Sylvia Zohrabian ◽  
Molly Karlinsey
Keyword(s):  
Acetic Anhydride ◽  
Chromatographic Separation ◽  
Chemical Derivatization ◽  
Carbohydrate Analysis ◽  
Simple Chemical

Carbohydrate analysis poses many analytical challenges, in terms of extraction, chromatographic separation, and detection.

Coulometric generation of acetylions by oxidation of mercury in acetic anhydride and in acetic acid/acetic anhydride mixture

1988 ◽  
Vol 212 ◽  
pp. 73-79 ◽  
Author(s):  
V. Vajgand ◽  
R. Mihajlović ◽  
Lj. Mihajlović ◽  
V. Joksimović
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride
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