Yu. V. Nelyubina

Neuroprotective Activity of (+)-(S)-2-[(1S,5R)-(3,7-Dioxo-2,4,6,8-Tetraazabicyclo[3.3.0]oct-2-yl)]-4-methylthiobutanoic acid

A study of the neurotropic, neuroprotective, and antioxidant action of the enantiomers and racemate of 2-[(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)]-4-methylthiobutanoic acid synthesized in a stereoselective reaction of (R)-, (S)-, or (R,S)-N-carbamoylmethionine with 4,5-dihydroxyimidazolidine-2-one showed that only (+)-(S)-2-[(1S,5R)-(3,7-dioxo-2,4,6,8-tetraazabicyclo[3.3.0]oct-2-yl)]-4-methylthiobutanoic acid had neuroprotective properties. X-ray structure analysis showed that the predominating racemate of glycolurils is crystallized from aqueous solutions as a conglomerate. Antioxidant activity was not detected.

α-Amino azoles in the synthesis of heterocycles: VI. Synthesis and structure of cycloalkane-annulated pyrazolo[1,5-a]pyrimidines

Reactions of 4-aryl-1H-pyrazol-5(3)-amines with 2-acylcycloakanones and 2-acyl-5,5-dimethylcyclohexane-1,3-diones led to the formation of regioisomeric 6,7,8,9-tetrahydropyrazolo[1,5-a]quinazoline, 5,6,7,8-tetrahydropyrazolo[5,1-b]quinazoline, and 7,8-dihydro-6H-cyclopenta[e]pyrazolo[1,5-a]pyrimidine derivatives. The product structure was determined by X-ray analysis and 1H and 13C NMR spectroscopy.

Catalytic activity of new PdII-complexes of bidentate PIII—N—PIII-ligands in Suzuki—Miyaura reaction

A reaction of readily available bis(diphenylphosphino)amines with (PhCN)2PdCl2 was used to synthesize PdII-complexes [Pd{Ph2PN(R)PPh2}Cl2] (R = Pri, cyclo-C6H11, Ph), which exhibited a high activity in the cross-coupling of aryl bromides with phenylboronic acid.

β-Diphenylphosphorylated alkanones and related compounds: synthesis and structure

The reactions of diphenyl(diisopropyl)chlorophosphine with arylidene(heteroarylidene)-acetones and 3-benzylidenepentane-2,4-dione in the presence of acetic acid proceed at a high rate at room temperature to afford the corresponding β-diorganylphosphorylated alkanones and alkanediones in high yields. The reaction of diphenylchlorophosphine with 4-methoxybut-3-en-2-one and dibenzylideneacetone carried out under similar conditions at the equimolar reagent ratio can serve as a convenient method for the synthesis of unique β-diphenylphosphorylalkenones. The structures of compounds obtained were established by IR, Raman, and NMR spectroscopy and X-ray diffraction.

α-Thioureidoalkylation of functionally substituted ureas: I. Tandem cyclization and esterification in reactions of N-(carboxyalkyl)ureas with 1,3-dialkyl-4,5-dihydroxy-4,5-diphenylimidazolidine-2-thiones in alcohols

Acid-catalyzed reactions of N-(carboxyalkyl)ureas with 1,3-dialkyl-4,5-dihydroxy-4,5-diphenylimidazolidine-2-thiones in methanol or propan-2-ol led to the formation of previously unknown ω-(4,6-dialkyl-2-oxo-3a,6a-diphenyl-5-thioxooctahydroimidazo[4,5-d]imidazol-1-yl)alkanoic acids and their methyl and isopropyl esters. The structure of some esters was proved by X-ray analysis. Methyl (4,6-diethyl-2-oxo-3a,6adiphenyl-5-thioxooctahydroimidazo[4,5-d]imidazol-1-yl)acetate showed anxiolytic effect.

Functionalized mercaptoacetic and propionic acid amides: synthesis, cyclopalladation features, and catalytic activity of metal complexes

Upon treatment with thiophenol or neomenthyl mercaptane, chloroacetand propionamides with an additional Nor S-donor substituent in the amine part gave new multidentate ligands readily undergoing direct cyclopalladation in the reaction with PdCl2(NCPh)2. The realization of κ3-X, N, S-coordination (X = N, S) in the complexes obtained was confirmed by IR and NMR spectroscopy and, in some cases, by single-crystal X-ray crystallography. The evaluation of catalytic activity of the palladocycles in the Suzuki cross-coupling of aryl bromides with PhB(OH)2 allowed us to establish the principal structure—activity correlations.

Invariom approach as a new tool in electron density studies of ionic liquids: a model case of 1-butyl-2,3-dimethylimidazolium chloride BDMIM[Cl]

Modeling of the experimental electron density in an ionic liquid (IL), 1-butyl-2,3-methylimidazolium chloride, within the invariom approximation as compared to the multipole refinement of high-resolution X-ray diffraction data and periodic quantum chemical calculations shows the applicability of this approach for describing supramolecular organization in ILs. Although the invariom approximation explicitly ignores charge transfer occurring between the ions, it nevertheless reproduces the features of the H-bonds and much weaker interactions (stacking, C–H⋯π and H⋯H) at the same level or better than the conventional multipole refinement does. The invariom approximation thus makes experimental electron density studies of ILs, which are now scarce, a useful tool in searching for ‘structure–property’ relationships, as it entangles the complex interplay of interionic interactions that operate in ILs.

Generation and metathesis of azomethine imines in reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with het(aryl)methylidenemalononitriles

A new metathesis reaction of azomethine imines is found. Catalytic or thermal diaziridine ring opening of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes leads to azomethine imines reacting further with het(aryl)methylidenemalononitriles to give in situ new azomethine imines inaccessible by common synthetic methods. New azomethine imines are detected as pyrazolines formed via a 1,4-H shift and trapped by the [3+2] cycloaddition with various dipolarophiles to yield 1,5-diazabicyclo[3.3.0]octane derivatives bearing pharmacophoric heterocycles, e.g. furan, nitrofuran, thiophene, and indole. The best results are achieved in the Et2O·BF3-catalyzed reactions in ionic liquids.

Diastereoselective synthesis of 4,5-dihydroxyimidazolidin-2-ones (-thiones) and their structure

Studies on the synthesis of 4,5-dihydroxyimidazolidin-2-ones (-thiones) based on the condensation of ureas or thioureas with glyoxal or 1,2-dioxo-1,2-diphenylethane showed high diastereoselectivity in the formation of racemates (trans-diastereomers) of 4,5-dihydroxyimidazolidin-2-ones (-thiones) and meso-forms (cis-diastereomers) of 4,5-dihydroxy-4,5-diphenyl-1,3-dialkylimidazolidine-2-thiones; plausible mechanisms of their formation were suggested. X-ray diffraction studies confirmed structures of diastereomers for separate examples of racemates and meso-forms of 4,5-dihydroxyimidazolidin-2-ones (-thiones).

Synthesis and structure of azido-and amino-substituted dibenzoxazepinones

Abstract1,3-Dinitro[b, f][1,4]dibenzoxazepin-11(10H)-one enters nucleophilic substitution reactions with N-nucleophiles, azide ion preferably replacing the nitro group in position 3, whereas amines the one in position 1. Structures of the substitution products were confirmed by X-ray diffraction and 1H NMR NOE spectroscopy. The selectivity observed in the reaction with amines was supposed to be caused by the stabilization of the intermediate σ-complex with the NH…O intramolecular hydrogen bond.