Hooker’s ‘lapachol peroxide’ revisited

The structure of ‘lapachol peroxide’ was published by Hooker in 1936; however, we recently discovered a mistake in the originally proposed structure; the correct structure, according to X-ray spectroscopy, is given here.     

4,4′‐Di­bromo­benzo­phenone at 293 and 103 K

The structure of 4,4′‐di­bromo­benzo­phenone, C₁₃H₈Br₂O, was determined at two different temperatures (293 and 103 K). A phase transition was not detected in this temperature range. Its crystal structure was found to be isostructural with that of the di­iodo analogue, but not with the structure of the di­chloro derivative.     

N‐Benzyl‐N‐(4‐methoxy­phenyl)­cyclo­hex‐1‐ene­carbothio­amide

The crystal structure of the title thio­amide, C₂₁H₂₃NOS, was determined to investigate the relationship between the photostability in the solid state and the structure.     

Configuration and conformation of taibaihenryiin T isolated from <Emphasis Type="Italic">Phlomis umbrosa</Emphasis>

Taibaihenryiin T was isolated for the first time from Phlomis umbrosa Turcz, and its structure was elucidated on the basis of IR and NMR spectra analysis. Its molecular configuration, conformation, and crystal structure were also characterized by X-ray structure analysis. The infrequency of the C–O–O–C group is manifested in this molecular configuration, and hydrogen bonding assembles the molecules into a three-dimensional networking structure in the crystal.     

Crystal structure of hinokiol isolated from <Emphasis Type="Italic">Isodon henryi</Emphasis>

Hinokiol was isolated for the first time from Isodon henryi and the structure was elucidated on the basis of IR and NMR spectra analysis. Its molecular configuration, conformation, and crystal structure were also characterized by X-ray structure analysis. The infrequent H-π stacking and hydrogen bonding assemble the molecules of hinokiol into a three-dimensional network structure. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 229–230, May–June, 2007.     

N‐Methyl‐N‐[(Z)‐2‐phenyl­propenyl]­thio­benz­amide

The crystal structure of the title thio­benz­amide, C₁₇H₁₇NS, was determined to investigate the relationship between the photoreactivity in solid state and the structure. The geometry was confirmed to be the Z isomer.     

The synthesis and crystal structure of 2,6,9‐trimethyl‐4,8‐dinitro‐2,6,9‐triazabicyclo[3.3.1]nona‐3,7‐diene

The first preparation of title compound 1 is accomplished. Its heterocyclic structure was characterized spectroscopically and by X‐ray structure analysis.     

Synthesis of pyridazine derivatives through the unexpected intermediate 5‐amino‐ 4‐cyano ‐2,3‐dihydro‐furan‐2,3‐disulfonic acid disodium salt

An unexpected compound (5‐amino‐4‐cyano‐2,3‐dihydrofuran‐2,3‐disulfonic acid disodium salt, 4 ) was isolated from the reaction of glyoxale bis hydrogen sulfite disodium salt with malononitrile. Its structure was undoubtly identified through crystal structure analysis. Compound 4 was highly stable and it was isolated easily and in a very high yield. Its reactivity was studied in the reactions with some hydrazine derivatives in order to obtain different pyridazine analogs.     

SSZ‐27: A Small‐Pore Zeolite with Large Heart‐Shaped Cavities Determined by Using Multi‐crystal Electron Diffraction

The high‐silica zeolite SSZ‐27 was synthesized using one of the isomers of the organic structure‐directing agent that is known to produce the large‐pore zeolite SSZ‐26 ( CON ). The structure of the as‐synthesized form was solved using multi‐crystal electron diffraction data. Data were collected on eighteen crystals, and to obtain a high‐quality and complete data set for structure refinement, hierarchical cluster analysis was employed to select the data sets most suitable for merging. The framework structure of SSZ‐27 can be described as a combination of two types of cavities, one of which is shaped like a heart. The cavities are connected through shared 8‐ring windows to create straight channels that are linked together in pairs to form a one‐dimensional channel system. Once the framework structure was known, molecular modelling was used to find the best fitting isomer, and this, in turn, was isolated to improve the synthesis conditions for SSZ‐27.     

Effect of the microstructure of the supported catalysts CuO/TiO<Subscript>2</Subscript> and CuO/(CeO<Subscript>2</Subscript>-TiO<Subscript>2</Subscript>) on their catalytic properties in carbon monoxide oxidation

The effect of the microstructure of titanium dioxide on the structure, thermal stability, and catalytic properties of supported CuO/TiO₂ and CuO/(CeO₂-TiO₂) catalysts in CO oxidation was studied. The formation of a nanocrystalline structure was found in the CuO/TiO₂ catalysts calcined at 500°C. This nanocrystalline structure consisted of aggregated fine anatase particles about 10 nm in size and interblock boundaries between them, in which Cu²⁺ ions were stabilized. Heat treatment of this catalyst at 700°C led to a change in its microstructure with the formation of fine CuO particles 2.5–3 nm in size, which were strongly bound to the surface of TiO₂ (anatase) with a regular well-ordered crystal structure. In the CuO/(CeO₂-TiO₂) catalysts, the nanocrystalline structure of anatase was thermally more stable than in the CuO/TiO₂ catalyst, and it persisted up to 700°C. The study of the catalytic properties of the resulting catalysts showed that the CuO/(CeO₂-TiO₂) catalysts with the nanocrystalline structure of anatase were characterized by the high-est activity in CO oxidation to CO₂.     

Structure and electric properties of Na<Subscript>2</Subscript>SO<Subscript>4</Subscript>-NaPO<Subscript>3</Subscript> glasses

The influence of the SO₄²⁻ ion on the temperature and concentration dependences of electric conductivity and the structure of sodium phosphate oxide glasses was studied. The increased electric conductivity of sulfate-phosphate glasses was explained by the formation of mixed sulfate-phosphate fragments with terminal SO₄²⁻ ions in the structure of glasses in the Na₂SO₄-NaPO₃ system. The dissociation energies of the sodium sulfate fragments are lower than those of pure oxide sodium phosphate structural units. As a result, the number of dissociated sodium ions increases, the activation energy of electric conductivity falls, and the conductivity (at 25°C) increases approximately 270-fold relative to the conductivity of NaPO₃. The arrangement of SO₄²⁻ ions in the structure was evaluated from the IR spectra of the glasses.     

Synthesis of three-layered titanates BaLn<Subscript>2</Subscript>Ti<Subscript>3</Subscript>O<Subscript>10</Subscript> in systems with coprecipitated hydroxocarbonates

The synthesis of three-layered titanates BaLn₂Ti₃O₁₀ (Ln = La, Nd, Sm) in systems with coprecipitated hydroxocarbonates was studied. It was established that they are formed through an intermediate phase with a defective perovskite structure followed by its transformation into the three-layered structure by the ordering of vacancies and rare-earth element and barium atoms and subdivision into three-layered blocks. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 6, pp. 349–353, November–December, 2007.     

Sesquiterpene Lactones and Flavonoids from <Emphasis Type="Italic">Artemisia albida</Emphasis>

The five known lactones matricarin, austricin, canin, and achillin guaianolides and argolide germacranolide and the two flavonoids eupatilin and its 7-O-methyl ester were isolated for the first time from the aerial part of Artemisia albida Willd. The structure of eupatilin was confirmed by an x-ray structure analysis. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 568–570, November–December, 2005.     

Conformational polymorphs of 3‐cyclopropyl‐5‐(3‐methyl‐[1,2,4]triazolo[4,3‐a]pyridin‐7‐yl)‐1,2,4‐oxadiazole

The dipharmacophore compound 3‐cyclopropyl‐5‐(3‐methyl‐[1,2,4]triazolo[4,3‐a]pyridin‐7‐yl)‐1,2,4‐oxadiazole, C₁₂H₁₁N₅O, was studied on the assumption of its potential biological activity. Two polymorphic forms differ in both their molecular and crystal structures. The monoclinic polymorphic form was crystallized from more volatile solvents and contains a conformer with a higher relative energy. The basic molecule forms an abundance of interactions with relatively close energies. The orthorhombic polymorph was crystallized very slowly from isoamyl alcohol and contains a conformer with a much lower energy. The basic molecule forms two strong interactions and a large number of weak interactions. Stacking interactions of the `head‐to‐head' type in the monoclinic structure and of the `head‐to‐tail' type in the orthorhombic structure proved to be the strongest and form stacked columns in the two polymorphs. The main structural motif of the monoclinic structure is a double column where two stacked columns interact through weak C—H…N hydrogen bonds and dispersive interactions. In the orthorhombic structure, a single stacked column is the main structural motif. Periodic calculations confirmed that the orthorhombic structure obtained by slow evaporation has a lower lattice energy (0.97 kcal mol^?1) compared to the monoclinic structure.     

Synthesis of dense ceramics of single-phase mayenite (Ca<Subscript>12</Subscript>Al<Subscript>14</Subscript>O<Subscript>32</Subscript>)O

The nanoporous material mayenite was synthesized by two methods: solid-phase and self-propagating high-temperature (combusting) (SHS) syntheses. The structure of the materials was determined by the X-ray diffraction analysis and IR and Raman spectroscopy.     

Synthesis and crystal structure of cytisino-<Emphasis Type="Italic">N</Emphasis>-(2-hydroxyethyl)-thiocarbamide

A thiourea derivative of the alkaloid cytisine was synthesized by reacting it with 1-propargyloxyethoxyethylisothiocyanate. It was shown that the synthesized acetal thiourea derivative underwent hydrolysis in acidic medium to cytisino-N-(2-hydroxyethyl)-thiocarbamide, the molecular structure of which was confirmed by an x-ray structure analysis. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 56–58, January–February, 2009.     

Poly[(μ2‐2,2‐dimethylpropane‐1,3‐diyl diisocyanide)‐μ2‐nitrato‐silver(I)]: a powder study

In order to investigate the effect of counter‐anions on the polymeric structure of (2,2‐dimethylpropane‐1,3‐diyl diisocyanide)silver(I) complexes, the novel title polymeric compound, [Ag(NO₃)(C₇H₁₀N₂)]_n, has been synthesized. The crystal structure was determined by simulated annealing from X‐ray powder diffraction data collected at room temperature. The current structure is similar to the recently reported structure of the analogue with chloride replacing nitrate. This study illustrates that both the chloride and nitrate complexes crystallize in the orthorhombic system in the Pbca space group with one monomer in the asymmetric unit, and also gives a strong indication that the counter‐anion does not have a considerable effect on the polymeric structure of the complex. The Ag centre lies in a distorted tetrahedral environment and is bonded to two 2,2‐dimethylpropane‐1,3‐diyl diisocyanide ligands to form chains. The nitrate anions crosslink the Ag centres of the chains to form a two‐dimensional polymeric network structure.     

l‐Isoleucyl‐l‐phenyl­alanine dihydrate

The structure of the title compound, C₁₅H₂₂N₂O₃·2H₂O, was derived from data collected on a very thin twinned needle. The peptide mol­ecule is in a rare conformation normally associated with hydro­phobic dipeptides that form nanotubes. Nevertheless, the present structure is divided into hydro­phobic and hydro­philic layers.     

The Photocyclodimers of 2,3‐Dihydro‐2,2‐dimethyl‐4H‐pyran‐4‐one

On irradiation (350 nm) in benzene solution, dihydropyranone 3 affords predominantly (75%) the cis‐anti‐cis HH‐dimer 4 , but in smaller amounts (12%) also dimer 5 , wherein one of the six‐membered rings is trans‐fused to the (central) cyclobutane ring. The constitution and configuration of 5 was fully elucidated by NMR‐analysis. On contact with SiO₂, 5 isomerizes quantitatively to the cis‐anti‐cis HT‐dimer 7 , the structure of which was established by X‐ray crystal‐structure determination.     

1,4,6,9‐Tetraoxa‐5λ4‐selena‐spiro[4.4]nonane – A Combined Theoretical and Experimental Study

The symmetric spiro‐selenurane derived from ethylene glycol, 1,4,6,9‐tetraoxa‐5λ⁴‐selena‐spiro[4.4]nonane, was prepared from selenium tetrachloride and ethylene glycol and its molecular structure was determined by single crystal X‐ray diffraction. NBO analyses for the title compound and a related compound were conducted to assess the role of the stereochemical active lone pair on the selenium atom on the structure.