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.

STUDIES ON RDX AND RELATED COMPOUNDS: X. ANALYSIS FOR NITRIC ACID IN ACETIC ACID – ACETIC ANHYDRIDE MEDIA

1953 ◽  
Vol 31 (3) ◽  
pp. 214-215 ◽  
Author(s):  
R. A. Marcus ◽  
C. A. Winkler
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Analytical Method ◽  
Potassium Acetate ◽  
Standard Solution ◽  
Related Compounds

An analytical method has been developed for the estimation of nitric acid in acetic acid – acetic anhydride media, with a precision of 0.3%. The procedure involves the addition of a solution of potassium acetate in acetic acid to the sample. The excess is back-titrated conductometrically with a standard solution of nitric acid in acetic acid.

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.

Flavan derivatives. XII. Conversion of Flavan-3,4-cis-diols into trans-Diacetates, and a new route to 3,4-trans-Diacetoxy-2,3-cis-flavans

1965 ◽  
Vol 18 (1) ◽  
pp. 90
Author(s):  
JW Clark-Lewis ◽  
LR Williams
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Bromine Atom ◽  
Potassium Acetate ◽  
Reductive Dehalogenation ◽  
Lithium Aluminium Hydride ◽  
Lithium Aluminium ◽  
Convenient Route ◽  
In Cis

Reaction of trans-trans-3-bromoflavan-4-ols with ethanolic potassium acetate is shown to lead to 2,3-cis-3,4-trans-4-ethoxy- and -4-acetoxy-flavan-3-ols, as well as to 2,3-cis-flavan-3,4-trans-diols. Flavan-3,4-cis-diols are converted into 3,4-trans-diacetates by acetylation with a mixture of acetic acid, acetic anhydride, and potassium acetate. cis-cis-Flavan-3,4-diols are thus converted into 3,4-trans-diacetoxy-2,3-cis-flavans, and 2,3-trans-flavan-3,4-cis-diols give trans-trans-diacetates. Epimerization of cis-cis-glycols to cis-trans-diacetates provides the most convenient route to 3,4-trans-3',4'-dimethoxy-6-methyl-2,3-cis-flavan, and to the corresponding 4'-methoxy analogue, and reduction with lithium aluminium hydride then gives the 2,3-cis-flavan-3,4-trans-diols. 3',4'-Dimethoxy-6-methyl-2,3-cis-flavan-3,4-trans-diol prepared in this way was converted into the corresponding carbonate, which is the first example of a 2,3-cis-3,4-trans-carbonate and completes the set of the four possible racemates in this series. The bromine atom is unreactive in cis-cis-3-bromo-3',4'- dimethoxy-6-methylflavan, but reductive dehalogenation with lithium aluminium hydride gave the ,β-flavan-4-ol (2,4-cis).

STUDIES OF RDX AND RELATED COMPOUNDS: III. THE REACTION TO FORM RDX FROM AMMONIUM NITRATE AND FORMALDEHYDE IN ACETIC ANHYDRIDE

1951 ◽  
Vol 29 (5) ◽  
pp. 377-381 ◽  
Author(s):  
A. Gillies ◽  
H. L. Williams ◽  
C. A. Winkler
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Acetic Anhydride ◽  
Ammonium Nitrate ◽  
Glacial Acetic Acid ◽  
Related Compounds

This reaction at 35°C. exhibits a behavior indicative of the presence of an intermediate in the reaction. Reaction of paraformaldehyde and ammonium nitrate in glacial acetic acid resulted in the isolation of hexamine dinitrate. Evidence is presented to indicate that formation of hexamine dinitrate, accompanied by the production of nitric acid, is responsible for the production of RDX in the acetic anhydride system.

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.

scholarly journals Rearrangements in the acid-catalyzed formation of lactones from 2-hydroxynorbornane-2-acetic acid derivatives and related compounds

1992 ◽  
Vol 70 (9) ◽  
pp. 2491-2501 ◽  
Author(s):  
Peter Yates ◽  
Magdy Kaldas
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Ethyl Esters ◽  
Alkyl Groups ◽  
Acid Lactone ◽  
Concentrated Sulfuric Acid ◽  
Acid Catalyzed ◽  
Preliminary Study ◽  
Related Compounds ◽  
Acetic Acids

A mixture of the epimeric ethyl 2-hydroxynorbornane-2-acetates (1) on treatment with concentrated sulfuric acid is converted in turn to the lactones of exo-2-hydroxynorbornane-1-acetic acid (4), endo-6-hydroxynorbornane-endo-2-acetic acid (5), and exo-3-hydroxynorbornane-exo-2-acetic acid (6). With trifluoroacetic acid or 50% sulfuric acid, 1 gives 4, but this does not react further. In concentrated sulfuric acid the parent acids of 1 (7) and (E)- and (Z)-(norborn-2-ylidene)acetic acids (8 and 9) and their ethyl esters (10 and 11) give 6 as the infinity product. A mixture of 5-norbornene-endo- and exo-2-acetic acid (30 and 31) on treatment with 50% sulfuric acid gives 4, 5, 6, and exo-2-hydroxynorbornane-syn-7-acetic acid lactone (33). Routes are proposed for the formation of the lactones that involve protonation and carbocation formation followed by rearrangement via Wagner–Meerwein, endo-6,2-hydride, and exo-3,2-hydride shifts in decreasing order of preference. It is postulated that the usual inhibition of the rearrangement of tertiary to secondary norbornyl carbocations is not operative when the third substituent is a carboxymethyl group or its derivatives because of the electron-withdrawing properties of such groups relative to simple alkyl groups. A preliminary study has shown that exo-5-acetyloxy-endo-2-hydroxynorbornane-exo-2-acetic acid (35) with 50% sulfuric acid gives four products that are considered to be the γ-lactones of endo-5-acetyloxy- and endo-5-hydroxynorbornane-1-acetic acid (38 and 39) and exo-2-acetyloxy-1-hydroxy-and 1,2-dihydroxynorbornane-syn-7-acetic acid (40 and 41). Protonation of either the hydroxyl or acetyloxyl group is postulated, giving two carbocations that undergo rearrangements as in the case of 1, together with 3,2-hydroxyl shifts. The structures of the lactones are assigned on the basis of spectroscopy, reactivity, and analogy. The reactions of the lactones, which lead to a variety of hydroxy- and oxonorbornaneacetic acids, illustrate their synthetic potential.

scholarly journals Comparative study of the performance of acetylated bamboo with different catalysts

BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 44-58
Author(s):  
Saisai Huang ◽  
Zhongqing Ma ◽  
Yujing Nie ◽  
Fengzhu Lu ◽  
Lingfei Ma
Keyword(s):  
Acetic Acid ◽  
Sulfuric Acid ◽  
Dimensional Stability ◽  
Color Change ◽  
Potassium Acetate ◽  
Color Difference ◽  
Phyllostachys Pubescens ◽  
Oh Groups ◽  
Weight Percentage ◽  
Concentrated Sulfuric Acid

The catalytic acetylation of bamboo (Phyllostachys pubescens) was compared with acetylation using concentrated sulfuric acid, acetic acid, potassium acetate, and noncatalytic acetylation at 120 °C for 3 h. The weight percentage gain, dimensional stability, color difference, and wettability of bamboo after the acetylation was comprehensively measured. Also, the chemical and thermal properties of the resultant bamboo were characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis. The results showed that the potassium acetate-catalyzed acetylation of bamboo greatly accelerated the reaction degree, had little effect on color change, extraordinarily decreased wettability, and had little irregular impact on the dimensional stability. The catalytic activity was followed by potassium acetate, sulfuric acid, noncatalytic acid, and acetic acid. The FTIR analysis showed that the functional groups in the acetylated bamboo were mainly affected by different catalysts. The thermal stability of acetylated bamboo was higher than the untreated bamboo. In particular, potassium acetate-catalytic acetylation greatly reacted with -OH groups and increased thermal decomposition.

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.

THE BROMINOLYSIS OF CARBOHYDRATE IODIDES: II. A SYNTHETIC ROUTE TO 2,5-ANHYDROSUGARS

1964 ◽  
Vol 42 (3) ◽  
pp. 547-549 ◽  
Author(s):  
R. U. Lemieux ◽  
B. Fraser-Reid
Keyword(s):  
Acetic Acid ◽  
Hydrogen Chloride ◽  
Potassium Acetate ◽  
Quantitative Yield ◽  
Equimolar Mixture ◽  
Silver Acetate ◽  
Synthetic Route ◽  
Fold Excess

Reaction of methyl 2-deoxy-2-iodo-β-D-glucopyranoside triacetate with a 20-fold excess of bromine and a 10-fold excess of silver acetate in a 10% solution of potassium acetate in acetic acid gave a near-quantitative yield of an equimolar mixture of the anomeric forms of 1,3,4,6-tetra-O-acetyl-2,5-anhydro-1-methoxy-D-mannose. Treatment of the mixture with methanolic hydrogen chloride gave the dimethylacetal of 2,5-anhydro-D-mannose (chitose).

Sign in / Sign up

Export Citation Format

Share Document