Photoinduced Intramolecular Bifurcate Hydrogen Bond: Unusual Mutual Influence of the Components

A series of 7-hydroxy-2-methylidene-2,3-dihydro-1<i>H</i>-inden-1-ones with 2-pyrrolyl (<b>3</b>), 4-dimethylaminophenyl (<b>4</b>), 4-nitrophenyl (<b>5</b>), and carboxyl group (<b>6</b>) as substituents at the exocyclic double bond was synthesized in the form of the E-isomers (<b>4</b>–<b>6</b>) or predominantly as the <i>Z</i>-isomer (<b>3</b>) which in solution is converted to the E-isomer. The synthesized compounds and their model analogues were studied by NMR spectroscopy, X-ray analysis, and MP2 theoretical calculations. The E-isomers having intramolecular O–H···OC hydrogen bond are converted by UV irradiation to the Z-isomers having bifurcated O–H···O···H–X hydrogen bond. Unexpected shortening (and, thus, strengthening) of the O–H···OC component of the bifurcated hydrogen bond upon the formation of the CO···H–X hydrogen bond was found experimentally, proved theoretically (MP2), and explained by a roundabout interaction of the H-donor (HX) and H-acceptor (CO) via the system of conjugated bonds

New class of bicyclic compounds derived from thiobarbituric acid with representative compound 1,3-diethyl-7-hydroxy-5,5,7-trimethyl-2-thioxo-1,2,3,5,6,7-hexahydro-4H-pyrano[2,3-d]pyrimidin-4-one. Preparation, crystal structure, mass spectrometry and IR spectroscopy

The colorless crystals of 1,3-diethyl-7-hydroxy-5,5,7-trimethyl-2-thioxo-1,2,3,5,6,7-hexahydro-4H-pyrano[2,3-d]pyrimidin-4-one (1) have been crystallized from the solution containing 1,3-diethyl-2-thiobarbituric acid (HDETBA) and equal volumes of concentrated HCl and acetone A possible stoichiometric reaction mechanism has been suggested. The crystal structure of 1 has been determined by X-ray single crystal analysis. The phase purity of the precipitate has been verified by powder X-ray diffraction analysis. Compound 1 crystallizes in the orthorhombic structure, space group P212121, with cell parameters a = 9.7454(4), b = 11.2225(4), c = 13.9171(5) Å, Z = 4, V = 1522.1(1) Å3. The molecules of 1 contain the bicyclic ring constructions new in thiobarbiturates. The molecules of 1 are linked by Osingle bondH⋯O hydrogen bonds to infinite molecule chains. The results of mass spectrometric analysis, theoretical studies and IR spectroscopy confirm the structure of 1. Using the PASS software, the general pharmacological potential of 1 was analyzed

Synthesis and Structure of <i>N</i>-(1-(Bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-yl)benzenesulfonamide

A new bicyclic sulfonamide derivative, N-(1-(bromomethyl)-7,7-dimethylbicyclo[2.2.1]heptan-2-yl)benzenesulfonamide, was synthesized in the reaction of benzenesulfonamide and camphene in the presence of N-bromosuccinimide in acetonitrile. The proposed mechanism of investigated reaction involves the Wagner–Meerwein rearrangement stage. 3-(Bromomethylene)-2,2-dimethylbicyclo[2.2.1]heptane was isolated as a minor product. The products were characterized by IR, NMR spectroscopy, X-ray diffraction analysis, HRMS and elemental analysis data

New class of bicyclic compounds derived from thiobarbituric acid with representative compound 1,3-diethyl-7-hydroxy-5,5,7-trimethyl-2-thioxo-1,2,3,5,6,7-hexahydro-4H-pyrano[2,3-d]pyrimidin-4-one. Preparation, crystal structure, mass spectrometry and IR spectroscopy

The colorless crystals of 1,3-diethyl-7-hydroxy-5,5,7-trimethyl-2-thioxo-1,2,3,5,6,7-hexahydro-4H-pyrano[2,3-d]pyrimidin-4-one (1) have been crystallized from the solution containing 1,3-diethyl-2-thiobarbituric acid (HDETBA) and equal volumes of concentrated HCl and acetone A possible stoichiometric reaction mechanism has been suggested. The crystal structure of 1 has been determined by X-ray single crystal analysis. The phase purity of the precipitate has been verified by powder X-ray diffraction analysis. Compound 1 crystallizes in the orthorhombic structure, space group P212121, with cell parameters a = 9.7454(4), b = 11.2225(4), c = 13.9171(5) Å, Z = 4, V = 1522.1(1) Å3. The molecules of 1 contain the bicyclic ring constructions new in thiobarbiturates. The molecules of 1 are linked by Osingle bondH⋯O hydrogen bonds to infinite molecule chains. The results of mass spectrometric analysis, theoretical studies and IR spectroscopy confirm the structure of 1. Using the PASS software, the general pharmacological potential of 1 was analyzed

The cis-trans isomer transformation spectroscopic and thermal properties of Li, Na, K 1,3-diethyl-2-thiobarbiturate complexes

Three new complexes of 1,3-diethyl-2-thiobarbituric acid (C8H11N2O2S, HDETBA) with Li+, Na+, K+ alkali ions were synthesized. The complexes have been prepared by neutralization of 1,3-diethyl-2-thiobarbituric acid with the corresponding metal hydroxide in aqueous solution. The colorless crystals have been investigated using X-ray single crystal and powder techniques and characterized by differential scanning calorimetry, thermogravimetry and infrared spectroscopy. The compounds of MDETBA with M = Li and M = Na crystallize in the monoclinic lattice with a = 10.678(1) Å, b = 7.2687(9) Å, c = 13.202(2) Å, β = 108.841(2)°, Z = 4, V = 969.8(2) Å3, S.G. P21/n and a = 10.534(2) Å, b = 7.604(1) Å, c = 14.186(1) Å, β = 108.964(4)°, Z = 4, V = 1074.6(3) Å3, S.G. P21/n, respectively. Сompound KDETBA crystallizes in the orthorhombic lattice with a = 4.2541(6) Å, b = 14.739(2) Å, c = 16.635(3) Å, Z = 4, V = 1043.1(3) Å3, S.G. P212121. In Li(I) and Na(I) complexes, the DETBA− ion is in cis-configuration and, in the K(I) complex, this ion is in trans-configuration. The reason for the transformation from cis- to trans-configuration has been rationalized

The cis-trans isomer transformation spectroscopic and thermal properties of Li, Na, K 1,3-diethyl-2-thiobarbiturate complexes

Three new complexes of 1,3-diethyl-2-thiobarbituric acid (C8H11N2O2S, HDETBA) with Li+, Na+, K+ alkali ions were synthesized. The complexes have been prepared by neutralization of 1,3-diethyl-2-thiobarbituric acid with the corresponding metal hydroxide in aqueous solution. The colorless crystals have been investigated using X-ray single crystal and powder techniques and characterized by differential scanning calorimetry, thermogravimetry and infrared spectroscopy. The compounds of MDETBA with M = Li and M = Na crystallize in the monoclinic lattice with a = 10.678(1) Å, b = 7.2687(9) Å, c = 13.202(2) Å, β = 108.841(2)°, Z = 4, V = 969.8(2) Å3, S.G. P21/n and a = 10.534(2) Å, b = 7.604(1) Å, c = 14.186(1) Å, β = 108.964(4)°, Z = 4, V = 1074.6(3) Å3, S.G. P21/n, respectively. Сompound KDETBA crystallizes in the orthorhombic lattice with a = 4.2541(6) Å, b = 14.739(2) Å, c = 16.635(3) Å, Z = 4, V = 1043.1(3) Å3, S.G. P212121. In Li(I) and Na(I) complexes, the DETBA− ion is in cis-configuration and, in the K(I) complex, this ion is in trans-configuration. The reason for the transformation from cis- to trans-configuration has been rationalized

Regio- and Stereoselective Synthesis of (Z,Z)-Bis(3-amino-3-oxo-1-propenyl) Selenides and Diselenides Based on 2-propynamides: A Novel Family of Diselenides with High Glutathione Peroxidase-like Activity

The efficient regio- and stereoselective syntheses of (Z,Z)-bis(3-amino-3-oxo-1-propenyl) selenides and diselenides in high yields based on the nucleophilic addition of sodium selenide to 2-propynamides and sodium diselenide to 3-(trimethylsilyl)-2-propynamides have been developed. The first examples of the addition of a selenium-centered nucleophile to 2-propynamides with a terminal triple bond and diselenide anion to 3-(trimethylsilyl)-2-propynamides have been carried out. Bis(3-amino-3-oxo-1-propenyl) diselenides are a novel family of compounds, none of which has yet been described in the literature. The glutathione peroxidase-like activity of the obtained compounds has been evaluated and products with high activity have been found. It was established that diselenides are superior to selenides with the same substituents in glutathione peroxidase-like activity. The results of the structural studying of products by single-crystal X-ray diffraction analysis and 77Se-NMR data are discussed

Facile one-pot synthesis of 5-substituted isoxazoles and pyrazoles through microwave-promoted intramolecular cyclization of γ-hydroxyalkynal oximes and hydrazones

<p>Simple and efficient one-pot synthesis of 5-substituted isoxazoles and pyrazoles has been developed. The formation of the target isoxazoles and pyrazoles is initiated by 1,2-nucleophilic addition of generated in situ hydroxylamine or hydrazine to α-acetylenic γ-hydroxyaldehydes with further intramolecular cyclization of the adducts. The protocols are associated with readily available substrates, simple procedure, short reaction time, and moderate to high yields.</p

The Structure and Properties of Fe(II) 1,10-Phenanthroline-Thiobarbiturate

Методом РСА определена структура (cif-file CCDC № 1831367) моноядерного комплекса [Fe(Bipy)(H2O)2(Htba)2]∙6H2O (I), где Bipy = 2,2’-дипиридил и Н2tba = 2-тиобарбитуровая кислота. Кристаллы I ромбические: a = 17.4697(7), b = 11.7738(4), c = 13.4314(5) Å, V = 2762.6(2), пр. гр. Pnma, Z = 4. В экваториальной плоскости октаэдрического комплекса расположены два атома азота молекулы Bipy и две молекулы воды, а два S-координированных иона Htba− занимают аксиальные позиции. Структура стабилизирована многочисленными водородными связями N−H∙∙∙O, O−H∙∙∙O, С−H∙∙∙O, C−H∙∙∙S и π–π-взаимодействием между молекулами Bipy и ионами Нtba−. Соединение охарактеризовано методами порошковой рентгенографии, термического анализа и ИК-спектроскопииThe structure of the mononuclear complex [Fe(Bipy)(H2O)2(Htba)2]∙6H2O (I), where Bipy – 2,2’-dipyridine, H2tba – 2-thiobarbituric acid (C4H4N2O2S), was determined by single crystal X-ray diffraction technique (cif-file CCDC No. 1831367). Crystals I are rhombic: a = 17.4697 (7), b = 11.7738 (4), c = 13.4314 (5) Å, V = 2762.6(2) Å3, space group Pnma, Z = 4. Two nitrogen atoms of the Bipy molecule and two water molecules are located in the equatorial plane of the octahedral complex, and two S-coordinated Htba− ions the axial positions are occupied. The structure is stabilized by N−H∙∙∙O, O−H∙∙∙O, С−H∙∙∙O, C−H∙∙∙S intermolecular hydrogen bonds and π–π interaction between Bipy and Htba−. The compound is characterized by the methods of powder X-ray diffraction, thermal analysis, and IR spectroscop