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

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.

Download Full-text

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

Magnetic Resonance in Chemistry ◽

10.1002/mrc.1266 ◽

2003 ◽

Vol 41 (11) ◽

pp. 959-961 ◽

Cited By ~ 1

Author(s):

Heidi M. Hultman ◽

Kristina Djanashvili ◽

Joop A. Peters

Keyword(s):

Acetic Acid ◽

Acetic Anhydride ◽

Nmr Study ◽

Hydrolysis Of

Download Full-text

Baeyer-Villiger Oxidation of 10-Methyl-9-Anthraldehyde: Formation and Photochemical Dimerization of 9-Formyloxy-10-methylanthracene

Australian Journal of Chemistry ◽

10.1071/ch9881977 ◽

1988 ◽

Vol 41 (12) ◽

pp. 1977 ◽

Cited By ~ 1

Author(s):

HD Becker ◽

BW Skelton ◽

AB Turner ◽

AH White

Keyword(s):

Molecular Structure ◽

Hydrogen Peroxide ◽

Acetic Acid ◽

Sulfuric Acid ◽

Diffraction Study ◽

Crystalline State ◽

X Ray Diffraction ◽

X Ray ◽

Tail Structure ◽

Villiger Oxidation

Oxidation of 10-methyl-9-anthraldehyde with hydrogen peroxide in acetic acid in the presence of sulfuric acid gives 9-formyloxy-10-methylanthracene which dimerizes in solution upon exposure to light. The head-to-tail structure of the 4π+4π photodimer was established by a single-crystal X-ray diffraction study. In the crystalline state, the molecular structure is centrosymmetric, and the length of the photochemically formed bonds 1.646(4)Ǻ. Crystals are monoclinic, P21/c, a 7.980(5), b 16.143(7), c 9.571(3)Ǻ, β 114.38(3)°, Z=2 dimers; R was 0.041 for 1362 'observed' diffractometer reflections.

Download Full-text

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

Journal of Chemical Research ◽

10.3184/030823405774309014 ◽

2005 ◽

Vol 2005 (7) ◽

pp. 461-468 ◽

Cited By ~ 7

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.

Download Full-text

Highly polar potential metabolites of the neuroleptic agent oxyprothepin: Synthesis of 2-hydroxy-8-methylsulfonyl and 3-hydroxy-8-methylsulfonyl derivatives of 10-[4-(3-hydroxypropyl)piperazino]-10,11-dihydrodibenzo[b,f]thiepin

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19850519 ◽

1985 ◽

Vol 50 (2) ◽

pp. 519-537 ◽

Cited By ~ 2

Author(s):

Jiří Jílek ◽

Jiří Holubek ◽

Emil Svátek ◽

Jiří Schlanger ◽

Josef Pomykáček ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Acetic Acid ◽

Potassium Carbonate ◽

Neuroleptic Agent ◽

Boron Tribromide ◽

Derivatives Of ◽

Methoxybenzoic Acid

The acid XI, obtained by reaction of (2-iodo-5-methoxyphenyl)acetic acid with 4-(methylsulfonyl)thiophenol (VIII) in dimethylformamide in the presence of potassium carbonate and copper, was transformed via intermediates XIIa-XIVa to compound XVa. Demethylation with boron tribromide afforded compound III, the potential metabolite of oxyprothepin (II). Its oxidation with hydrogen peroxide in acetic acid gave the sulfoxide XVII, which is a further potential metabolite. A reaction of 2-iodo-4-methoxybenzoic acid with VIII and potassium carbonate in dimethylformamide in the presence of copper afforded the acid XIX whose ester XXI was reduced with diborane to the alcohol XXII; hydrogenolysis to compound XXIII was also observed. The alcohol XXII was processed via compounds XXIV and XXV to the acid XXVI which was cyclized in a low yield to the ketone XIIb. A further processing via the intermediates XIIIb and XIVb led to compound XVb. Demethylation gave compound IV, another potential metabolite.

Download Full-text

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

Rubber Chemistry and Technology ◽

10.5254/1.3546650 ◽

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.

Download Full-text

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

Clinical Chemistry ◽

10.1093/clinchem/2.5.353 ◽

1956 ◽

Vol 2 (5) ◽

pp. 353-368 ◽

Cited By ~ 131

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.

Download Full-text