NMR study of the synthesis of17O-enriched acetic acid by hydrolysis of acetic anhydride with17O-enriched water

2003 ◽  
Vol 41 (11) ◽  
pp. 959-961 ◽  
Author(s):  
Heidi M. Hultman ◽  
Kristina Djanashvili ◽  
Joop A. Peters
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Nmr Study ◽  
Hydrolysis Of

Synthetic application of cyclobutanes V. α-Carbalkoxymethylation of α, β-unsaturated ketones

1977 ◽  
Vol 55 (5) ◽  
pp. 822-830 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Patrick Chi-Lin Yao
Keyword(s):  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Acetic Anhydride ◽  
Potassium Carbonate ◽  
Alkyl Iodide ◽  
Keto Ester ◽  
Unsaturated Ketones ◽  
Synthetic Application ◽  
Hydrolysis Of ◽  
Villiger Oxidation

Two general methods for α-carbalkoxymethylation of both enolizable and nonenolizable (towards the γ-position) α,β-unsaturated ketones have been developed. Method A involves three synthetic steps: photocycloaddition of the starting enone to 1,1-dimethoxyethylene, hydrolysis–oxidation of the adduct with acetic acid and 30% hydrogen peroxide, and O-alkylation of the resulting mixture of lactone and acid using anhydrous potassium carbonate and an alkyl iodide, e.g., 13 → 17 → 21 + 22 → 23. Method B differs from method A in the means of securing the required cyclobutanone intermediate. Thus, photocycloaddition of 13 to vinyl acetate followed by hydrolysis of the adduct gave two epimeric keto alcohols 39 whose oxidation with dimethyl sulfoxide and acetic anhydride afforded diketone 40. Baeyer–Villiger oxidation of 40 followed by methylation of the products 21 and 22 completed the overall α-carbomethoxymethylation process to give keto ester 23.

Fluorine-containing Heterocycles: Part II Synthesis and Reactions of New Thieno[2,3-b]Pyridine Derivatives Bearing Trifluoromethyl Group

2005 ◽  
Vol 2005 (7) ◽  
pp. 461-468 ◽  
Author(s):  
Abdu E. Abdel-Rahman ◽  
Etify A. Bakhite ◽  
Elham A. Al-Taifi
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Formic Acid ◽  
Triethyl Orthoformate ◽  
Trifluoromethyl Group ◽  
Pyridine Derivatives ◽  
Unexpected Product ◽  
Acyl Azide ◽  
Hydrolysis Of ◽  
Heterocyclic Aldehydes

Ethyl [3-cyano-6-(2-thienyl)-4-trifluoromethylpyridin-2-ylthio]acetate (2) and ethyl 3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carboxylate (3) were prepared by reaction of 3-cyano-6-(2-thienyl)-4-trifluoromethylpyridine-2(1H)-thione (1) with ethyl chloroacetate. The reaction of both 2 and 3 with hydrazine hydrate under different conditions was studied. The main products were [3-cyano-6-(2-thienyl)-4-trifluoromethyl-2-pyridinylthio]acetohydrazide (4) and 3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carbohydrazide (5). The condensation of acethydrazide 4 with some aromatic or heterocyclic aldehydes yielded the corresponding hydrazones 6a–d which underwent intramolecular Thorpe–Ziegler cyclisation to give the N1-aryl or heteroaryl-methylene-3-amino-6-(2-thienyl)-4-trifluoromethylthieno[2,3-b]pyridine-2-carbohydrazides (7a–d). Treatment of 7a–d with triethyl orthoformate led to the formation of pyridothienopyrimidine derivatives 8a–d. Heating carbohydrazide 5 with acetic acid gave an unexpected product which was assigned as 3-amino-2-methyl-7-(2-thienyl)-9-trifluoromethylpyrido[3′,2′:4,5] thieno[3,2-d]pyrimidine-4(3H)-one (12). Moreover, the reaction of 5 with other reagents such as acetic anhydride, formic acid, acetylacetone and/or triethyl orthoformate were carried out and their products were identified. Diazotisation of 5 produced the corresponding acyl azide 18 which underwent Curtius rearrangement to furnish the imidazolone derivative 20. Hydrolysis of the ester 3 gave the aminoacid 21 which in turn was converted into the oxazinone derivatives 22 and 23. Recyclisation of 22 and 23 into some pyrimidinone derivatives (12 and 24–26) was carried out.

The Course of Autoöxidation Reactions in Polyisoprene and Allied Compounds. III. The Oxidation of Rubber in the Presence of Acetic Acid or Acetic Anhydride

1944 ◽  
Vol 17 (2) ◽  
pp. 267-276
Author(s):  
George F. Bloomfield
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Chain Scission ◽  
Considerable Proportion ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Free Hydroxyl ◽  
Hydrolysis Of ◽  
Oxygenated Products ◽  
Oxidative Attack

Abstract Oxidation of rubber by oxygen in the presence of acetic anhydride leads to formation of highly oxygenated products containing a considerable proportion of acetoxyl groups. The residual unsaturation of the products of highest acetoxyl content, taken in conjunction with other analytical characteristics, indicates that three, rather than two, acetoxyl groups normally combine with each isoprene unit attacked. Although the bulk of the oxygen introduced is present in the form of acetoxyl groups, a portion occurs as carboxyl and carbonyl groups; also, whenever acetic acid is used (partly or wholly) in place of acetic anhydride, some free hydroxyl groups appear in the oxidized rubber. The proportions of carboxyl and carbonyl groups observed can be correlated satisfactorily with the extent of chain-scission occurring during the oxidation, the groups in question forming the new ends of the severed molecules. Hydrolysis of the acetylated products yields hydroxy acids, which readily undergo lactonic elimination of water. Acetic anhydride and acetic acid can clearly act as auxiliary reagents in autoöxidation reactions, and the detailed results obtained with rubber can be best accounted for on the basis of α-methylene peroxidation, followed by decay reactions involving incorporation of the auxiliary reagent as well as oxidative attack at the double bonds of the rubber.

Simplified Rapid Technic for the Extraction and Determination of Serum Cholesterol without Saponification

1956 ◽  
Vol 2 (5) ◽  
pp. 353-368 ◽  
Author(s):  
Julius J Carr ◽  
I J Drekter
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Total Cholesterol ◽  
Simple Procedure ◽  
Cholesterol Esters ◽  
Color Development ◽  
Acid Catalyzed ◽  
Hydrolysis Of ◽  
Room Lighting

Abstract An accurate yet simple procedure for the determination of total cholesterol, based upon the application of a Liebermann-Burchard color reaction directly in the solvent employed for extraction of cholesterol from serum, has been described. Extraction of cholesterol and removal of protein are accomplished by means of acetic acid and acetic anhydride. Serum water is removed by the acid-catalyzed hydrolysis of acetic anhydride. The Liebermann-Burchard color is then developed with a stable, modified reagent consisting of equal volumes of H2SO4 and acetic acid. Excellent agreement with the technic of Schoenheimer and Sperry is obtained. Equal intensities of color are produced by equivalent concentrations of free and esterified cholesterol. Preliminary saponification of cholesterol esters is therefore not required. Color development may proceed in ordinary room lighting without loss of accuracy.

Hydrolysis of Acetic Anhydride in Concentrated Acetic Acid without Catalysis

1957 ◽  
Vol 49 (2) ◽  
pp. 197-201 ◽  
Author(s):  
H. J. Janssen ◽  
C. H. Haydel ◽  
L. H. Greathouse
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Hydrolysis Of

Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽  
2015 ◽  
Vol 14 (4) ◽  
pp. 237-244 ◽  
Author(s):  
JONI LEHTO ◽  
RAIMO ALÉN
Keyword(s):  
Acetic Acid ◽  
Betula Pendula ◽  
Cooking Time ◽  
Hot Water ◽  
Partial Hydrolysis ◽  
Chemical Pulping ◽  
Black Liquors ◽  
Aliphatic Carboxylic Acids ◽  
Hydrolysis Of ◽  
Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

Synthesis of conjugates of 1-(carboxymethyl)cytosine and 1-(5-O-carboxymethyl-β-D-arabinofuranosyl)cytosine with proteins

1979 ◽  
Vol 44 (10) ◽  
pp. 3023-3032 ◽  
Author(s):  
Helmut Pischel ◽  
Antonín Holý ◽  
Günther Wagner
Keyword(s):  
Human Serum Albumin ◽  
Acetic Anhydride ◽  
Serum Albumin ◽  
Human Serum ◽  
Activated Esters ◽  
Hydrolysis Of

1-(Carboxymethyl)cytosine (Ia), 1-(5-O-carboxymethyl-β-D-arabinofuranosyl)cytosine (IIa) and 5'-O-carboxylmethylcytidine (IIIa) were transformed by treatment with acetic anhydride and 4-dimethylaminopyridine to the peracetyl derivatives Ib-IIIb. These products reacted with p-nitrophenol in the presence of N, N'-dicyclohexylcarbodiimide to give the activated esters Ic-IIIc which on reaction with ammonia, dimethylamine or 2-aminoethanol afforded the corresponding carboxamides Id-IIId, IIe,f. Reactions of Ic and IIc with human serum albumin and bovine γ-globulin at pH 9.2, followed by hydrolysis of the N- or O-acetyl groups at pH 9.5, gave 50% up to 64% yields of the respective conjugates Ig, IIg and Ih, IIh.

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.

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