Structures of hexamethyl-[1,1'-biphenyl]-4,4'-diammonium salts.

The crystal structures of nine hexamethyl-[1,1'-biphenyl]-4,4'-diammonium (HMB) salts are described: the iodide (2), triiodide (3), succinate (4), fumarate (5), tetravanadate (6), hydroterephthalate (7) and perylenetetracarboxylate (8), as well as pentamethyl-[1,1'-biphenyl]-4,4'-diammonium iodide (1) and the metal-organic framework sodium diacetylenedisalicylate-HMB (9). HMB carbonate (10) has been synthesized as an important intermediate for a promising anti-metal-organic framework (`anti-MOF'). All the described compounds are characterized by high solubility in water.

Effect of a halogen bond on the crystal structure of terphenyldicarboxylic acid derivatives.

The syntheses and structures of dimethyl [1,2:2,3-terphenyl]-1,3-dicarboxylate (1), dimethyl 2,2-diiodo[1,2:2,3-terphenyl]-1,3-dicarboxylate (2), potassium [1,2:2,3-terphenyl]-1,3-dicarboxylate (3) and dimethyl [1,1'-biphenyl]-4,4'-dicarboxylate (4) are reported. Neighboring phenyl rings in compounds 1, 3 and 4 have a planar structure (torsion angles are 0.6-4.

Novel 1,2,4-Triazole- and Tetrazole-Containing 4-Thiopyrano[2,3-]quinolines: Synthesis Based on the Thio-Michael/aza-Morita-Baylis-Hillman Tandem Reaction and Investigation of Antiviral Activity.

A novel method for synthesizing 1,2,4-triazole- and tetrazole-containing 4-thiopyrano[2,3-]quinolines using a new combination of the thio-Michael and aza-Morita-Baylis-Hillman reactions was developed. Target compounds were evaluated for their cytotoxicities and antiviral activities against influenza A/Puerto Rico/8/34 virus in MDCK cells. The compounds showed low toxicity and some exhibited moderate antiviral activity.

Protonated Organic Diamines as Templates for Layered and Microporous Structures: Synthesis, Crystal Chemistry, and Structural Trends among the Compounds Formed in Aqueous Systems Transition Metal Halide or Nitrate-Diamine-Selenious Acid.

Systematic studies of crystalline compounds formed in aqueous systems containing aliphatic diamines, divalent transition metal halides, and selenious acid resulted in the discovery of a large family of new complex species corresponding to several new structure types. With ethylenediamine (en), layered (enH)[(HSeO)] compounds are the most commonly formed species which constitute a significant contribution to the family of layered hydrogen selenites containing neutral [(HSeO)] ( = Mg, Mn, Co, Ni, Cu, Zn, Cd) 2 building blocks. In contrast to some previous suggestions, piperazine (pip), as well as its homologue N-methylpiperazine, mostly give rise to quite different, sometimes more complex, structures of varied dimensionality while the (pipH)[(HSeO)] compounds are formed only with = Cu and Cd.

Divergent Synthesis of Pyrazolo[1,5-]pyridines and Imidazo[1,5-]pyridines via Reagent-Controlled Cleavage of the C-N or C-C Azirine Bond in 2-Pyridylazirines.

The three-membered ring in 2-(2-pyridyl)azirine-2-carboxylic esters and thioesters can undergo selective cleavage of either the N-C2 bond under copper(II) catalysis or the C-C bond under the action of HCl to provide isomeric azirine ring expansion products of pyrazolo[1,5-]pyridine or imidazo[1,5-]pyridine series, respectively. Mild catalytic reaction conditions for the formation of pyrazolopyridines make it possible to obtain them directly from 4-bromoisoxazoles by a one-pot, three-stage procedure without isolating the intermediate 2-bromoazirines and 2-(2-pyridyl)azirines.

Development of Fluorescent Isocoumarin-Fused Oxacyclononyne - 1,2,3-Triazole Pairs.

Fluorescent isocoumarin-fused cycloalkynes, which are reactive in SPAAC and give fluorescent triazoles regardless of the azide nature, have been developed. The key structural feature that converts the non-fluorescent cycloalkyne/triazole pair to its fluorescent counterpart is the pi-acceptor group (COOMe, CN) at the C6 position of the isocoumarin ring. The design of the fluorescent cycloalkyne/triazole pairs is based on the theoretical study of the S1 state deactivation mechanism of the non-fluorescent isocoumarin-fused cycloalkyne IC9O using multi-configurational ab initio and DFT methodologies.

Azirine-triazole hybrids: selective synthesis of 5-(2-azirin-2-yl)-, 5-(1-pyrrol-2-yl)-1-1,2,3-triazoles and 2-(5-(2-azirin-2-yl)-1-1,2,3-triazol-1-yl)pyridines.

Azirine-triazole hybrids, 1--5-(3-aryl-2-azirin-2-yl)-1-1,2,3-triazoles, were selectively synthesized by reaction of 1-(3-aryl-2-azirin-2-yl)-2-(triphenylphosphoranylidene)ethanones with tosyl and ()-2-benzoylvinyl azides in high yields at rt. The reaction with 2-azidopyridine makes it possible to obtain azirine-triazole-pyridine hybrids, albeit in moderate yields, at 170 °C. The mechanism and selectivity of the reaction of α-carbonylphosphoranes with azides are discussed on the basis of DFT calculations.

Multicomponent Assembly of Trisubstituted Imidazoles and Their Photochemical Cyclization into Fused Polyheterocyclic Scaffolds.

A straightforward route to a large and diverse library of trisubstituted imidazoles was established via a three-component reaction of 2-oxoaldehydes, 1,3-dicarbonyl compounds, and acyclic nitrogen bis-nucleophiles. The obtained products were subsequently explored in a photochemical cyclization yielding a variety of imidazole-fused polycyclic compounds.

New cyclic diarylheptanoids from the false heartwood of Ehrh.

Two undescribed (- and five known cyclic diarylheptanoids (-) were isolated from the false heartwood of white birch ( Ehrh.). All structures were elucidated through extensive 1D and 2D NMR experiments and HR-ESI-MS data, along with comparison of their spectroscopic data with those reported in the literature.

Nucleophile-Induced Rearrangement of 2-Azirine-2-carbonyl Azides to 2-(1-Tetrazol-1-yl)acetic Acid Derivatives.

2-Azirine-2-carbonyl azides undergo a rearrangement into derivatives of 2-(1-tetrazol-1-yl)acetic acid when interacting with O- and S-nucleophiles at room temperature. The reaction is catalyzed by tertiary amines or hydrazoic acid. The reaction with primary alcohols and phenols gives alkyl/aryl 2-(1-tetrazol-1-yl)acetates.

Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings.

A wide range of derivatives with new pyrido[2,1-]pyrrolo[3,4-]isoquinoline skeleton was synthesized by free-radical intramolecular cyclization of -bromophenyl-substituted pyrrolylpyridinium salts using the (TMS)SiH/AIBN system. The cyclization provides generally good yields of pyrido[2,1-]pyrrolo[3,4-]isoquinoline hydrobromides having no additional radical-sensitive substituents. The free bases can be obtained from the synthesized hydrobromides in quantitative yield by basification at room temperature.

Combination of "Buttressing" and "Clothespin" Effects for Reaching the Shortest NHN Hydrogen Bond in Proton Sponge Cations.

A series of previously unknown 2,4,5-tri- and 2,4,5,7-tetrasubstituted 1,8-bis(dimethylamino)naphthalenes and their salts with HBF containing bulky spherically shaped substituents (Me, Br, and SiMe) in the naphthalene ring has been synthesized. Using XRD analysis of 11 samples, the influence of the so-called "buttressing" and "clothespin" effects on their molecular structure and the NHN hydrogen bond geometry in the solid cations were investigated. The combined action of both effects has been shown to significantly increase the compression of the hydrogen bond.