A Short Synthesis of 4- and 6-Azaindol-2(3H)-ones

Although indol-2(3H)-ones possess a wide range of pharmacological¹ and microbiological² activities, the corresponding azaindol-2(3H)-ones have stimulated little interest. Successful syntheses have been reported for the title compounds^3,4 involving several stages which in our hands gave a variety of side products, especially in the hydrogenation stage.     

Synthesis of 1-substituted 3-nitroquinolin-4(1H)-ones

A versatile synthetic method for preparing 1-substituted 3-nitroquinolin-4(1H)-ones from corresponding 2-fluoro-α-nitroacetophenones is demonstrated by the synthesis of 6,7-difluoro derivatives 7a-c . The method involves sequential treatment of the starting nitroacetophenone with triethyl orthoformate and the appropriate amine, followed by a nucleophilic cyclization reaction under mild conditions. The C-7 fluorine atom of 7 can be displaced by cyclic amines. Substituted 6-fluoro-7-(4-methyl-1-piperazinyl)-3-nitroquinolin-4(1H)-ones 8a-c were prepared in this way.     

Synthesis and properties of 6-methyl-4-(m-nitrophenyl)-3-cyanopyridin-2(1H)-ones,the corresponding pyridine-2(1H)-thiones,and their hydrogenated analogs

The condensation of 4-pyridylacetone, m-nitrobenzaldehyde, and cyanoacetamide (cyanothioacetamide) in the presence of bases was used to obtain 5-pyridyl-substituted 6-methyl-4-(m-nitrophenyl)-3-cyanopyridin-2(1H)-ones, the corresponding pyridine-2(1H)-thiones, and their hydrogenated analogs. 2-Carbamoylmethylthiopyridine was isolated in the alkylation of 5-(4-pyridyl)pyridine-2(1H)-thione with iodoacetamide under mild conditions, while 2-carbamoylthio-5-(N-carbamoylmethyl-4-pyridyl)pyridine iodide was isolated under more severe conditions.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1674–1679, December, 1991.     

Synthesis of 3-(Dialkylamino)-4-halofuro[3,4-c]pyridin-1(3H)-ones

Russian Journal of Organic Chemistry - The reaction of 4-halo-3-hydroxyfuro[3,4-c]pyridin-1(3H)-ones with acyclic and alicyclic secondary amines in ethyl acetate afforded the corresponding...     

Synthesis of 2-Alkyl（aryl）-3-methylthio-6-methyl-6-arylpyrano-[4, 3-c]pyrazol-4（2H）-ones

The synthesis of 2-alkyl(aryl)-3-methylthiopyrano[4,3-c]pyrazol-4(2H)-ones via 5, 6-dihydro-2H-pyran-2, 4-dione-3-dithioacetals with (un)substituted hydrazines is described and the mechanism of the formation of title compounds is discussed. Their structures were confirmed by ^1HNMR spectra and elemental analysis.     

Dehalogenation of 1-methyl-5-halo-4-substituted-pyridazin-6-ones

In order to confirm the regiochemistry for the functionalization of 1-(1,1-dibromo-2-oxopropyl)-4,5-dihalopyridazin-6-ones, the dehalogenation of 1-methyl-5-halo-4-substituted-pyridazin-6-ones using Pd/C and hydrogen was carried out. The results of the title reaction are reported.     

Synthesis of 4(6)-amino-6(4)-halo-2,1,3-benzoxadiazoles

By reactions of 4-amino-2,6-dihalonitrosobenzenes with sodium azide and 4,6-dihalo-2,1,3-benzoxadiazoles with amines a group of 2,1,3-benzoxadiazole aminoderivatives was prepared.     

Hydrogenation of substituted 1-arylisoquinolin-3(2H)-ones to 5, 6, 7, 8-tetrahydro- and 1, 4-dihydroisoquinolin-3(2H)-ones

Catalytic hydrogenation of variously substituted 1-arylisoquinolin-3(2H)-ones 1 gave, depending on the substituents, 5, 6, 7, 8-tetrahydroisoquinolin-3(2H)-ones ( 2 ) and/or the corresponding 1, 4-dihydro derivatives 3 . Saturation of the compounds fused with benzene ring furnished as the main products the 9, 10-dihydro- ( 4 and 5 ) and 5, 6-dihydroisoquinolin-3(2H)-ones ( 6 ) in the case of benzo[f] and benzo[h] anellation, respectively, in addition to the 1, 4-dihydro compounds detected or isolated as by-products.     

Photoisomerization of 2H,6H-Thiin-3-ones to 2-(Alk-1-enyl)thietan-3-ones

Reaction of 3-bromo-3-methylbutan-2-one ( 1 ) with mercapto-esters 2 affords 5-oxo-3-thiahexanoates 3 which cyclize to thiane-3,5-diones 4 . Conversion of these dicarbonyl compounds to their ethyl enol ethers 5–7 followed by reduction with LiAlH₄ gives 2H,6H-thiin-3-ones 8–10 . On irradiation (350 nm) in either MeCN, benzene, or i-PrOH, these newly synthesized heterocycles isomerize efficiently to 2-(alk-l-enyl)thietan-3-ones 11–13 . The rearrangement seems to proceed from an excited singlet state, as it is not quenched by naphthalene, and also occurs with the same efficiency in the presence of added alkene. A (9-S-3) sulfuranyl-alkyl biradical formed by bonding of C(α) of the enone C?C bond on sulfur is discussed as possible intermediate.     

Tautomerism and electron impact mass spectra of pyrimidin-4(3H)- and -4(1H)-ones

A mass spectrometric identification and differentiation of pyrimidin-4(3H)- and -4(1H)-ones was carried out. N-Substitution at position 1 or 3 made the distinction of the two sets of compounds very easy because of their characteristic fragmentation pathways. Most interesting were the spectra of the N-unsubstituted derivatives, which illustrated a predominance of the two possible NH tautomers in relation to the 4-hydroxy structure.     

Synthesis of 4-amino-6-chloro-1,3,5-triazin-2(1H)-ones

Conditions for selective substitution for one chlorine atom in 2-(R,R??-amino)-4,6-dichloro-1,3,5-triazines with a hydroxide ion were elaborated. Spectral and calculation methods showed that the products formed are in the lactam form, i.e., have the structure of 4-chloro-6-(R,R??-amino)-1,3,5-triazin-2(1H)-ones.     

One-pot Multicomponent Synthesis,Spectroscopy, Crystal Structures and Theoretical Calculations of 3-Cyano-4-(4-hydroxy-3-methoxyphenyl)-6-phenyl-2(1H)-pyridinone and 3-Cyano-4-chlorophenyl-6-(4-tolyl)-2(1H)-pyridinone

Pyridinone derivatives are of great interest in medicinal chemistry where they were found to be potent to various diseases. Their metal complexes added more value to their applications. Here, we have synthesized two 2-pyridinone derivatives(3-cyano-4-(4-hydroxy-3-methoxyphenyl)-6-phenyl-2(1 H)-pyridinone and 3-cyano-4-chlorophenyl-6-(4-tolyl)-2(1 H)-pyridinone) using one-pot multicomponent system. They were well characterized using spectroscopic techniques like nuclear magnetic resonance(NMR-1 H 13 C), Fourier transform infrared(FT-IR) and UV/Vis spectroscopy. The final structures were determined using single-crystal X-ray diffraction technique which helps us to determine their geometries. Density functional theory(DFT) and time-dependent density functional theory(TD-DFT) with suitable basis-sets of calculations have correctly simulated these spectroscopic parameters. The intramolecular charge transfer(ICT) of both substrates has been discussed using natural bond orbital(NBO) technique. Molecular electrostatic potential(MEP) surfaces showed their reactive locations for intermolecular charge transfer. Compared to p-nitroaniline(pNA), both substrates were shown to have substantial molecular hyperpolarizability.     

Synthesis of 2,3-Dihydroquinazoline-4(1H)-ones

An efficient, inexpensive, and heterogeneous catalyst, [Al(H₂PO₄)₃], was applied in a three-component, one-pot cyclocondensation reaction of isatoic anhydride with primary amines (or ammonium salts) and aldehydes to afford the corresponding quinazolinone derivatives in excellent yields. Reactions occurred under thermal solvent-free conditions. It was found that this solid acidic catalyst could be easily recovered and reused for at least three cycles without any loss of activity.     

Synthesis of new derivatives of 6-(1-adamantylmethyl)-4(3H)-pyrimidinone

Russian Journal of Organic Chemistry -     

Synthesis of 3-(aminooxoethyl)-6-methyl-1-(thiethan-3-yl)-pyrimidine-2,4-(1H,3H)-diones

A new approach to prepare 2-chloroacetamides has been developed, based on the reaction of chloroacetyl chloride with excess of secondary amines. Alkylation of 6-methyl-1-(thiethan-3-yl)pyrimidine-2,4(1H,3H)-dione with the synthesized 2-chloroacetamides in the presence of potassium carbonate has afforded N ³-acetamido-substituted 6-methyl-1-(thiethan-3-yl)pyrimidine-2,4(1H,3H)-diones.     

Synthesis of 6-Alkylthio-5-carbamoyl-3-cyano-4-phenyl-3,4-dihydropyridin-2(1H)-ones

Condensation of ethyl benzylidenecyanoacetate with thiocarbamoylacetamide in the presence of an equimolar amount of piperidine produces piperidinium 5-carbamoyl-3-cyano-2-oxo-4-phenyl-3,4-dihydropyridine-6(1H)-thiolate, which is then used in synthesis of the corresponding 6-alkylthiosubstituted 3,4-dihydropyridin-2(1H)-ones. Dedicated to Professor Henk van der Plas on his 70th birthday. Latvian Institute of Organic Synthesis, Riga LV-1006 Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 506–509, April, 1999.     

5-(3,4-dichlorophenyl)-3-{[4-(2-pyridyl)piperazine-1-yl]methyl}-1,3,4-oxadiazole-2(3H)-one: Synthesis, characterization, X-ray and DFT structures

5-(3,4-Dichlorophenyl)-3-{[4-(2-pyridyl)piperazine-1-yl)]methyl}-1,3,4-oxadiazole-2(3H)-one C₁₈H₁₇Cl₂N₅O₂ (3) is synthesized and characterized by IR, ¹H NMR, ¹³C NMR, elemental analyses, single-crystal X-ray diffraction, and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). All data obtained from the spectral studies support the structural properties of 3. The molecules are linked principally by C-H??O hydrogen bonds involving carbonyl atoms and carboxylate O atoms, forming R ₂ ² (16) and R ₄ ² (20) rings that link to give a one-dimensional network of molecules. An extensive two-dimensional network of C-H??O hydrogen bonds and ?С??? interactions are responsible for crystal stabilization.