Pyrimidones 1. Synthesis of some 1-substituted-5-aryl- and (4,5-diaryl)-2(1H)pyrimidones

A series of 1-substituted-5-aryl-2(1H)pyrimidones has been prepared by a method involving condensation of an appropriate N-substituted urea with either 2-aryl-3-(dimethylamino)-acroleins or 2-arylmalondialdehydes. On biological investigation, several compounds exhibited some antiinflammatory activity.     

Synthesis of N-Substituted Maleimides as Potential Antineoplastic Sulfhydryl Agents

For a purpose of antineoplastic screening, a series of sulfhydryl-binding agents, N-substituted maleimides was prepared. These compounds were obtained by dehydration of the corresponding maleamic acids under suitable conditions in which the formation of maleisoimide by-products was prevented, IR and UV spectra, as well as the elemental analyses confirmed the structural assignment of our products, A brief discussion on the preparation of N-(2,4-dinitrophenylamino)maleimide was also given.     

3-Aryl- or 3-(trans-4-alkylcyclohexyl)- 6-arylcyclohex-2-enones: synthesis,transformations and mesomorphic properties

The synthesis and chemical transformations of 3-aryl- or 3-(trans-4-alkylcyclohexyl)- 6-arylcyclohex-2-enones into liquid crystalline compounds are discussed. These 3,6-disubstituted cyclohex-2-enones were prepared by the condensation of appropriate Mannich salts or trans-4-alkylcyclohexyl 2-bromoethyl ketones with 4-substituted benzyl methyl ketones.     

Synthesis of isochroman-fused pyrazolone and pyrimidine derivatives

Unsubstituted 5 , and 2-aryl- 6a-c , or 2-(2-benzothiazolyl)-substituted 1,3-dihydroisochromano[4,3-c]pyrazol-3(2H)-ones 7a-f were prepared by the reactions of 3-ethoxyoxalyl- 2 , or 3-ethoxycarbonylisochroman-4-one 3 with hydrazine derivatives. The reactions with amidines gave 2-substituted 4-hydroxyisochromano[4,3-d]-pyrimidines 8a-c .     

Tetrazole compounds. 9. A new approach to tetrazolyl-substituted quinoline derivatives

The acid-catalyzed reaction of 1-aryl-5-(2-dimethylaminovinyl)-1H-tetrazoles 2 with arylamines suitably functionalized in the ortho-position resulted in Z-configurated transamination products which were cyclized to novel 3-tetrazolylquinolines by the action of sodium ethoxide. Thus, on reacting 2 with 2-aminoacetophenone or 2-aminobenzophenone, respectively, the 2-[2-(1-aryl-1H-tetrazol-5-yl)vinyl-amino]aryl ketones 3a-g were obtained, the cyclization of which gave 4-substituted 3-(1-aryl-1H-tetrazol-5-yl)quinolines 4 . In the case of the transamination products 3h-1 , prepared from 2 and methyl anthranilate, the ring closure afforded 3-(1-aryl-1H-tetrazol-5-yl)-1H-quinolin-4-ones 5 . Starting from 2 and anthranilonitrile 4-amino-3-(1-aryl-1H-tetrazol-5-yl)quinolines 10 were obtained via the corresponding intermediates 9 .     

Heterocyclizations of Functionalized Heterocumulenes with C,N- and C,O-Dinucleophiles: III.* Cyclization of N-(1-Aryl-1-chloro-2,2,2-trifluoroethyl)-N'-arylcarbodiimides with 3-Substituted 1-Phenylpyrazol-5-ones

Cyclization of N-(1-aryl-1-chloro-2,2,2-trifluoroethyl)-N'-arylcarbodiimides with 3-substituted 1-phenylpyrazol-5-ones yields 6-aryl-4-arylimino-1-phenyl-6-trifluoromethyl-1,4,5,6-tetrahydropyrazolo[4,3-e][1,3]oxazines.     

Effects of substituent and solvent on the structure and spectral properties of maleimide derivatives

The maximum absorption wavelength , emission wavelength (λ_em) and the related oscillator strength (f) of the maleimides in the ground and first excited states were calculated by using the DFT, CIS and the time-dependent density functional theory (TD-DFT) methods, where the molecular structures were optimized by DFT/B3LYP/6-31G^* calculation. Solvent effects on the maleimides were examined using the PCM simulation at DFT/B3LYP level with the 6-31G^* basis set. For N-substituted maleimide, the substituent gives only a slight influence on the maleimide chromophore, while planar conformation of PhMLH leads to the improvement in π-delocalization from substituent to maleimide unit. For 3,4-substituted maleimide, the steric repulsion between substituent and maleimide chromophore influences the extent of π-delocalization and the molecular conformation. The calculated and λ_em of maleimides are in good agreement with the experimental data. In the gas phase, both absorption and emission peaks are red-shift as compared to the non-substituted maleimide. Under solvent environment, the more planar conformation of PhMLH shows a blue-shift in the calculated and λ_em as compared with other N-substituted maleimides. For 3,4-substituted maleimides, the effect of substitution produces the most significant spectral red-shift as compared to other maleimides.     

Novel routes to 1-aryl-1,4-dihydro-3(2H)-isoquinolinones and 2-substituted or 2,3-disubstituted benzofurans by intramolecular cyclizations

N-(α-Benzotriazolylalkyl)arylacetamides, readily available from an arylacetamide, an aldehyde and benzotriazole, undergo intramolecular cyclization under acidic conditions to give 1-aryl-1,4-dihydro-3(2H)-isoquinolinones in good to excellent yields. Similarly, 2-(benzotriazol-1-yl)-2-(o-hydroxyphenyl)ethanols, obtained by lithiation of 2-(benzotriazol-1-ylmethyl)phenols followed by quenching with aldehydes or ketones, eliminate a molecule of water and a molecule of benzotriazole yielding 2-substituted and 2,3-disubstituted benzofurans.     

Stable azomethine imines derived from pyrazolidin-3-one and their cycloaddition to <Emphasis Type="Italic">N</Emphasis>-arylmaleimides

Reactions of (Z)-1-arylmethylidene-3-oxopyrazolidin-1-ium-2-ides (stable analogs of azomethine imines generated by thermal opening of the diaziridine fragment in 6-aryl-1,5-diazabicyclo[3.1.0]hexanes) with N-arylmaleimides having no ortho substituents in the aryl group are stereoselective: the products are mixtures of the corresponding cis and trans adducts, the latter prevailing (∼1.4–2.6: 1). trans Adducts are formed as the only products in the reactions with di-ortho-substituted N-arylmaleimides. (Z)-1-[(2,6-Dichlorophenyl) methylidene]-3-oxopyrazolidin-1-ium-2-ide reacts with both para- and ortho-substituted N-arylmaleimides to give exclusively trans adducts. Labile azomethine imines generated by thermolysis of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes are likely to have Z configuration as well.     

Reactions of Aliphatic Diazo Compounds: IV. Reaction of Diphenyldiazomethane with Substituted Imides of Maleic and Itaconic Acids

Diphenyldiazomethane regioselectively adds to 2-R-substituted maleimides to yield 1-pyrazoline derivatives, 1-R-7-aryl-6,8-dioxo-4,4-diphenyl-2,3,7-triazabicyclo[3.3.0]oct-2-enes that on heating liberate nitrogen to afford substituted 3-azabicyclo[3.1.0]hexanes. To the N-arylsubstituted imides of itaconic acid the diphenyldiazomethane adds to furnish 5-aryl-4,6-dioxo-1,1-diphenyl-5-azaspiro[2.4]heptanes.     

The synthesis of 7-(substituted-amino)-3-azabicyclo[3.2.0] heptanes

1,2-Cycloaddition reactions of several enamines with N-substituted maleimides and 4-phenyl-1,2,4-triazoline-3,5-dione have been carried out. The adducts were transformed into 7-(substituted-amino)-3-azabicyclo[3.2.0]heptanes and a 1,2,4-triazolidine-1-acetaldehyde, respectively. These are the first reported examples of 3-azabicyclo[3.2.0]heptanes substituted in any position other than the 3-position. The reaction of an ynamine with N-benzylmaleimide afforded a bicyclic intermediate which upon hydrolysis gave a 2,5-dioxo-3-pyrrolidineacetic acid.     

Double 1,3-dipolar cycloadditions of meso-ionic heterocycles to N-substituted maleimides

Double 1,3-dipolar cycloadditions of 2,4-diphenyl-3-methyloxazotium 5-oxide and 3-phenylsydnone to two molecules of N-substituted maleimide afforded one or two isomeric 4,8-iminobenzo[1,2-c:4,5-c′]dipyrrole-1,3,5,7-tetrone derivatives owing to the types of heterocycles as well as N-substituents of maleimides.     

Synthesis of a library of 2-aryl-2H-tetrazole-5-carboxamides for photoaffinity labeling of aminergic G-protein coupled receptors

A four-step approach to 2-aryl-2H-tetrazole-5-carboxamides bearing GPCR-focused N-substituted piperazine residues involves ‘SAFE’ diazotransfer onto 1-(piperazin-1-yl)butane-1,3-diones followed by [3+2] cycloaddition of arenediazonium cations at the intermediate ααα-diazo acetamides. The compounds prepared are intended for photoaffinity labeling of aminergic G-protein coupled receptors.     

Synthesis and Transformations of 5-Substituted 2-Aryl-7H-[1,2,4]triazolo[3,2-b][1,3]thiazin-7-ones and 2-Aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones

3-Aryl-1,2,4-triazole-5-thiones react with dimethyl acetylenedicarboxylate and methyl 3-phenyl-propynoate to afford the corresponding 5-substituted 2-aryl-7H-[1,2,4]triazolo[3,2-b][1,3]thiazin-7-ones. Treatment of 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones with alkalies leads to formation of 3-(benzimidazol-2-ylsulfanyl)-3-arylpropionic acids, their reaction with methyl p-toluenesulfonate yields 1-(3-methyl-2-thioxo-2,3-dihydro-1N-benzimidazol-1-yl)-3-phenyl-2-propen-1-one, and oxidation with hydrogen peroxide gives benzimidazole-2-sulfonic acid and 3-aryl-2-propenoic acids.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 1, 2005, pp. 109–114.Original Russian Text Copyright © 2005 by Britsun, Esipenko, Chernega, Lozinskii.     

Synthesis of Azo-Sulfa Drugs Based on 2-Pyridinone and 2-Pyridinethione

Some new azo sulfa drugs 3-cyano-4,6-diphenyl-1-[4-(N-substituted)sulfamyl]phenylazo-2-pyridinone dyes (1-6) and 3-cyano-4,6-diphenyl-1-[4-(N-substituted)sulfamyl]phenylazo-2-pyridinethione dyes (1′-6′) were synthesized by coupling of 4-(N-substituted)sulfamylbenzene diazonium salts with 3-cyano-4,6-diphenyl-2-pyridinone and/or with 3-cyano-4,6-diphenyl-2-pyridin-ethione. The corresponding iron (1a-6a, 1′a-6′a), copper (1b-6b, 1′b-6′b) and mercury (1c-6c, 1′c-6′c) chelates wvere also prepared. All synthesized compounds were screened in vitro for antibacterial and antifungal activities.     

Synthesis, NMR and X-ray characterisation of 6-substituted 4-amino-5-aryldiazenyl-1-arylpyridazinium salts

A new simple method has been used to prepare 6-substituted 4-(subst. amino)-5-aryldiazenyl-1-arylpyridazinium salts from N-methyl- or N-aryl-3-amino-1-phenylbut-2-en-1-ones and 4-aminopent-3-en-2-ones and substituted benzenediazonium tetrafluoroborates or hexafluorophosphates. The structure of selected derivatives was studied by means of ¹⁵N NMR spectra and X-ray.     

Synthesis of 5-substituted 1-aryl-1H-pyrazole-4-acetonitriles, 4-methyl-1-phenyl-1H-pyrazole-3-carbonitriles and pharmacologically active 1-aryl-1H-pyrazole-4-acetic acids

Lithium aluminum hydride reduction of 5-substituted or unsubstituted ethyl or methyl 1-aryl-1H-pyrazole-4-carboxylates gave, generally in excellent yields, 5-substituted or unsubstituted 1-aryl-1H-pyrazole-4-methanols which afforded the corresponding 1-aryl-4-(bromomethyl)-1H-pyrazoles with hydrobromic acid in acetic acid solution. These crude intermediates gave by reaction with potassium cyanide in dimethylsulfoxide solution 1-aryl-1H-pyrazole-4-acetonitriles only in the case of 5-unsubstituted compounds, otherwise mixtures of 5-substituted 1-aryl-1H-pyrazole-4-acetonitriles and 4-methyl-1-phenyl-1H-pyrazole-3-carbonitriles were generally obtained. Acetonitriles IIIa,b,i,l gave in excellent yields the corresponding 1-aryl-1H-pyrazole-4-acetic acids Va,b,i,l by alkaline hydrolysis. Compounds Vb,i,l showed in the writhing test appreciable analgesic properties, associated with low acute toxicity; moreover, compound VI exhibited a statistically significant antiinflammatory activity in the carrageenan-induced edema assay.     

Synthesis of some newer 5-(5-aryl-2H-tetrazol-2-ylmethyl)-4-substituted-s-triazole-3-thiols as possible antiinflammatory agents

Several 1-(5-aryl-2H-tetrazol-2-ylacetyl)-4-substituted thiosemicarbazides and 5-(5-aryl-2H-tetrazol-2-yl-methyl)-4-substituted-s-triazole-3-thiols were synthesized as possible antiinflammatory agents. These compounds were characterized by their elemental, infrared and nuclear magnetic resonance analysis.     

Studies on the imidization of N-substituted polymaleamic acids

A spectral method for determining the imidization from maleamic acid to maleimide was described. The formation condition and mechanism of polymaleimide compared with N-phenyl-maleimide ( I ) and 4,4′-bis(N-maleimido)-diphenylmethane ( II ) were investigated. A series of N-substituted maleimides were synthesized by the reaction of their corresponding maleamic acids with acetic anhydride and sodium acetate as a catalyst. The rate of dehydration reaction of N-phenylmaleamic acid with Ac₂O was determined at a mole ratio 0.1:1 of NaOAc to N-phenyl-maleamic acid and a second-order constant K of 1.38 × 10^?2 (mL/mol s) was obtained. The activation energies for the ring-closure reaction of N-phenylmaleamic acid and polyphenylene-methylenemaleamic acid were 1.26 × 10⁴ (cal/g mol) and 1.32 × 10⁴ (cal/g mol), respectively. The decreasing order for the rate of N-substituted maleimide formation was N-(p-methylphenyl)maleimide > I ≒ II > N-(p-chlorophenyl)maleimide. The result was attributed to the para-substituent effect. These imidization reaction were observed qualitatively by IR spectra and analyzed quantitatively by ¹H-NMR spectra.     

Sensitive derivatization reagents for thiol compounds in high-performance liquid chromatography with electrochemical detection

Three N-substituted maleimides were tested as derivatizing reagents; N-(4-anilinophenyl) maleimide (APM) was the most favorable in terms of sensitivity and reactivity. N-Acetyl-l-cysrteine, glutathione, l-cysteine and d-penicillamine were readily converted into the adducts with APM. Picogram levels of these thiol compounds were separated and quantified.