Carbon-13 spectra of some tetrahydropyridines. The structure of the tetrahydropyridines from 3,5-lutidine 1-oxide and mercaptans in acetic anhydride

The reaction of 3,5-lutidine 1-oxide ( 1 ) with t-butyl mereaptan in acetic anhydride, with or without triethylamine, was reinvestigated. There was obtained 2-t-butylthio-3,.5-lutidine as the major product, a small quantity of 3-(t-bulylthio)methyl-5-picoline, 1-acetyl-2,3-diacetoxy-3,5-dirnethyl-6-t-butylthio-1,2,3,6-tetrahydropyridine (which represents a structure revision) and l-acetyl-2,6-dihydroxy-3-t-butylthio-3,5-dimethyl-1,2,3,6-tetrahydropyridine. A similar reaction of 1 with 1-adamantyl mercaptan furnished 2-(l-adamantylthio)-3,5-lutidine and 1-acetyl-2,3-diacetoxy-3,5-dimethyl-6-(1-adamantylthio)-1,2,3,6-tetrahydropyridine. The structures of these new tetrahydropyridines were established primarily by carbon-13 nmr spectra.     

The deoxydative substitution reactions of nicotinamide and nicotinic acid N-oxides by 1-adamantanethiol in acetic anhydride

The reaction of nicotinamide N-oxide with 1-adamantanethiol in acetic anhydride yielded a mixture of 2-and 6-(1-adamantylthio)nicotinamides (49%, in the ratio of 24:1) and 2-, 5-, and 6-(1-adamantylthio)nicotino-nitriles (18%, in the ratio of 79:1:20). From a reaction of nicotinic acid N-oxide with 1-adamantanethiol, there was isolated 2-(1-adamantylthio)nicotinic acid as the only sulfide in 23% yield. Carbon? sulfur bond cleavage took place when 2-(1-adamantylthio)nicotinic acid, or the corresponding amide or nitrile, were boiled with concentrated hydrochloric acid to furnish 2-mercaptonicotinic acid and 1-chloroadamantane, quantitatively. The reaction of nicotinamide N-oxide alone in acetic anhydride at 135° formed N-acetyl-2-hydroxynicotinamide (61%), 2-hydroxynicotinonitrile (0.5%) and N,N-diacetyl-2-acetoxynicotinamide (0.8%).     

Copper-catalyzed Perkin-acyl-Mannich reaction of acetic anhydride with pyridine: expeditious entry to unconventional piperidines

A regioselective introduction of a methoxycarbonyl methyl group at the C(2) position of unsubstituted pyridine has been accomplished with catalytic amounts of copper(II) triflate in mild reaction conditions. The N-acetyl-1,2-dihydropyridyl acetic acid methyl ester obtained is a valuable building block for the synthesis of new polyfunctionalized piperidine derivatives bearing unconventional substitution patterns.     

Reaction of 1,2-diarylhydrazines with acetic anhydride catalyzed by 4-(dimethylamino)pyridine

Summary A new method for the synthesis of 1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones3 and 4-acetyl-1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-ones5 is presented. The reaction of 4,4-disubstituted 1,2-diarylhydrazines1 with acetic anhydride in the presence of an equimolar amount of 4-(dimethylamino)pyridine leads to mixtures of the corresponding acetyl derivatives2 and3. Under the same conditions, 2,2-disubstituted 1,2-diarylhydrazines yield mixtures of3 and5.

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4-(Dimethylamino)pyridin-katalysierte Reaktion von 1,2-Diarylhydrazinen mit Essigsäureanhydrid

Zusammenfassung Eine neue Methode zur Synthese von 1,2-Diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-onen3 und 4-Acetyl-1,2-diaryl-1,2-dihydro-5-methyl-3H-pyrazol-3-onen5 wird beschrieben. Die Reaktion von 4,4-disubstituierten 1,2-Diaryl-hydrazinen1 mit Essigsäureanhydrid führt in Gegenwart eines Äquivalentes 4-(Dimethylamino)pyridin zu Gemischen der entsprechenden Acetylderivate2 und3. Unter den gleichen Bedingungen werden aus 2,2-disubstituierten 1,2-Diarylhydrazinen Gemische aus3 und5 erhalten.

     

过碳酸钠-醋酸酐作用下的Baeyer-Villiger反应

在醋酸酐介质中, 过碳酸钠可以与酮进行Baeyer-Villiger反应, 将它们氧化成相应的酯。其中脂环酮的反应结果较好, 环内酯的产率约为80%。芳香酮除芳环被活化的以外, 效果欠佳。当反应施加超声辐射后可显著加快反应速度, 并对过碳酸钠的作用机理进行了讨论。     

Further studies on the reaction of N-(2-Hydroxyphenyl)anthranilic acids with acetic anhydride

Reaction of N-(2-hydroxyphenyi)anthranilic acids (I) with acetic anhydride was investigated further. Treatment of Ia with refluxing acetic anhydride for 3 hours afforded two minor products, IIIa and IV, in addition to the previously reported IIa. Under similar conditions, the reaction of Ib with acetic anhydride afforded IIb as reported previously, and IIIb and IXb in small quantities. Treatment of IIIb with hydrazine gave X, and treatment of IXb with methoxyethylamine gave XI. When Ic was allowed to react with refluxing acetic anhydride, there were obtained three minor products, IIIc, IXc and XIII, in addition to IIc. Reaction of Id with acetic anhydride gave IId, and two minor products IXc and XIV. The formation of these minor products in the reaction of Ia-d with acetic anhydride are discussed based on the reation mechanism proposed previously for the formation of II.     

Tributylphosphine-catalyzed ring-opening reaction of epoxides and aziridines with acetic anhydride

Reactions of aziridines and epoxides with acetic anhydride catalyzed by an organophosphine provided the corresponding esters of β-amino alcohols and 1,2-diols in high yields, respectively.     

Coordination modes and reaction of acetic anhydride with tantalum pentafluoride

The composition and structure of compounds formed upon the reaction of equimolar amounts of TaF₅ and MeC(O)O(O)CMe in CH₂Cl₂ and upon dissolution of the fluoride in an anhydride excess have been studied by ¹⁹F NMR (293-183 K). It has been found that, in both cases, the anhydride is fluorinated to form MeC(O)F (a quartet at 47.7 ppm, J _FH = 18 Hz) and the MeC(O)O^? anion. In the spectra of the reaction mixture in CH₂Cl₂, the signals of pentafluoro complexes are assigned to the TaF₅[OC(Me)OC(O)Me] adduct and the TaF₅[OC(O)Me]^? anion; on the basis of the chemical shifts of the singlets, they are assigned to the TaF₄[OC(Me)OC(O)Me]⁺ and TaF₂[OCOC(O)Me] ₂ ³⁺ cations in which the anhydride acts as a chelating ligand. Upon the direct reaction of the reagents in an anhydride excess, the spectra at low temperatures show, in addition to the signal of the tetrafluoride cation, the signals of the hexafluorotantalate ion TaF ₆ ^? and four trifluoroacetate complexes. Close relative concentrations of the latter enable the suggestion that they form chain or cyclic structures. It is believed that, in these structures, the acetate group has monodentate and bridging coordination modes, while chelating coordination mode seems to be less probable.     

Deoxydative substitution of pyridine 1-oxides by thiols. Part XX. Reactions of (2, 3, and 4-phenyl)-, 3-acetamido-, 3-bromo-, 3-acetoxy-, 3-ethoxypyridine 1-oxides with 1-adamantanethiol in acetic anhydride

Substitutions of 2, 3, and 4-substituted pyridine 1-oxides by 1-adamantanethiol in acetic anhydride takes place at available α-, to a lesser degree at β-, and rarely at γ-ring carbons. It was found that 2-phenylpyridine 1-oxide produces a mixture of 5- and 6-(1-adamantylthio)-2-phenylpyridines, and 4-phenylpyridine 1-oxide a mixture of 2- and 3-isomeric sulfides. Substitutions of the 1-oxides of 3-phenyl-, 3-acetamido-, 3-acetoxy-, 3-bromo-, and 3-ethoxypyridine by 1-adamantanethiol in acetic anhydride led to mixtures consisting predominantly of 2- and 6-sulfide, and to a lesser extent, the 5-sulfide. When triethylamine is present in otherwise identical reaction mixtures, the ratio of α to β-sulfides increases. From the reactions of 3- and 4-phenylpyridine 1-oxides, there were isolated some N-acetyl hydroxy (or acetoxy) 1-adamantylthio substituted 1,2,3,4-and 1,2,3,6-tetrahydropyridines, whose structures are discussed.     

Structures of unsaturated acetic esters formed in the reaction of 2-pinene oxide with acetic anhydride

Summary The bicyclic acetate obtained in the reaction of 2-pinene oxide with acetic anhydride is a mixture of (–)-and (±)-trans-pinocarveol acetates; one of the monocyclic acetates obtained is a mixture of (+) and (±)-trans-carveol acetates.Translated from Izvestiya Akademii Nauk SSSR, Khimicheskaya, No. 12, pp. 2144–2152, December, 1965     

The reaction of phenylnitromethane with acetic anhydride/sodium acetate

Reaction of phenylnitromethane with acetic anhydride/sodium acetate at 80–85° produces N-benzoyl-N,O-diacetylhydroxylamine, which can be isolated in 30% yield. This compound was proposed previously as an intermediate in a similar reaction which had yielded only benzoic anhydride, triacetylhydroxylamine and acetanilide.     

Catalysis of reaction between ozone and 4-hydroxytoluene in acetic anhydride

Kinetics and products of 4-hydroxytoluene oxidation with ozone-air mixture in the presence of transition metal acetates as catalysts have been studied. Main steps of the catalytic series have been considered, and a mechanism of redox catalysis has been proposed which conforms to the experimental data and enables control over the direction, depth, and selectivity of the oxidation. Only manganese(II) acetate has been found to exhibit high catalytic activity in the presence of catalytic amounts of mineral acids. Manganese(II) acetate largely suppresses electrophilic reaction of ozone with the aromatic ring, so that the main reaction direction is oxidation of the methyl group with formation of 4-acetoxybenzyl acetate as the major product (62.6%) and 4-acetoxybenzylidene diacetate as a minor one (10.2%).     

Halogenation and nitration of 1-carboxymethyl-5-methyluracil. Halophilic reaction involving acetic anhydride

Russian Chemical Bulletin - 1-Carboxymethyl-5-halo-6-hydroxy-5-methyl-5,6-dihydrouracils and 1-carboxymethyl-6-hydroxy-5-methyl-5-mtro-5,6-dihydrouracils were synthesized for the first time by...     

Reaction of 2,3-diphenylpyrazine 1-oxides with acetic anhydride

Some 2,3-diphenylpyrazine 1-oxides were heated with acetic anhydride to give the corresponding 2,3-di-acetoxy-2,3-dihydro-5,6-diphenylpyrazines. By X-ray diffraction analysis, the configuration of two acetoxyl groups was determined to be trans.     

Regioselective synthesis of 2-(2-hydroxyaryl)pyridines from the reactions of benzynes with pyridine N-oxides

By modifying the conditions from those in Larock's reported synthesis of 3-(2-hydroxyaryl)pyridines from benzynes, and pyridine N-oxides, we altered the regioselectivity of the reaction toward an efficient synthesis of 2-substituted pyridines. The presence of ethyl propiolate altered the regioselectivity to afford 3-substituted pyridine products instead. We conducted appropriate control experiments that enable a full understanding of the mechanism.     

The reaction of cyclohexanone azine with cyanoacetic acid‐acetic anhydride

The reaction of cyclohexanone azine with a reagent produced by brief heating of cyanoacetic acid with acetic anhydride produced a highly substituted dihydropyrazolone.     

Reaction of N-(4-pyridylmethyl)-amide N-oxides with acetic anhydride

Reaction of N-(4-pyridylmethyl)-benzamide N-oxides with acetic anhydride yielded dimerization compounds. This dimerization occurs at the atom attached to the pyridine ring.