Synthesis of Schiff bases by aromatic amine condensation with 3,3′-bithiophenes-2,2′ and 4,4′-dicarbaldehydes

Reactions of aromatic amines with 3,3′-bithiophene-2,2′-dicarbaldehyde 1 and 3,3′-bithiophene-4,4′-dicarbaldehyde 2 gave the 2,2′-(N-(aryl)diimino)-3,3′-bithiophene 3 and 4,4′-(N-(aryl)diimino)-3,3′-bithiophene 4 in good yields. Orthophenylenediamine reacted with 1 and 2 to give dithieno[3,4-c;4′,3′-e]azepino[1,2-a]benzimidazole 5 and dithieno[2,3-c;3′,2′-e]azepino[1,2-a]benzimidazole 6. All these original products have been characterized by spectroscopic techniques and elemental analysis.     

Synthesis and some reactions of a 2,2′-biphospholyl

1,1′-Diphenyl-3,3′,4,4′-tetramethyl-2,2′,5,5′-tetrahydro-2,2′-biphosphole obtained by reductive dimerization of the appropriate phosphole has been converted into the corresponding 2,2′-biphosphole by P-bromination followed by dehydrobromination of the resulting P,P′-tetrabromo compound with α-picoline. This 2,2′-biphosphole gives two isomeric P-sulfides upon reaction with sulfur, and a Mo(CO)₄ chelate upon reaction with Mo(CO)₆. Cleavage of the two P-phenyl bonds by lithium in THF yields the corresponding biphospholyl anion, which is converted into a mixture of two isomeric bis(η⁵,η⁵-2,2′-diphosphafulvalene)diirons by treatment with FeCl₂. The reaction of Mn₂(CO)₁₀ in boiling xylene affords a mixture of three complexes, including a (η⁵,η⁵-2,2′-diphosphafulvalene)hexacarbonyldimanganese produced by thermal cleavage of the two PPh bonds. Under CO pressure there is a [1,5] P → C shift of the two phenyl groups, leading to formation of (η⁵,η⁵-3,3′-diphenyl-2,2′-diphosphafulvalene)hexacarbonyldimanganese.     

Synthesis and substrate-controlled reactions of 2,2′-unsaturated biquinazolinones

A series of BiQuinazolinones bearing either double or triple bonds in their lateral chains have been synthesized. These compounds were then subjected to substrate-controlled reactions such as Diels-Alder, epoxidation and Pauson-Khand reactions. The stereoselective outcome observed in these transformations is very promising for the future application of BiQuinazolinones as chiral auxiliaries.     

Electrochemical and spectroscopic properties of poly-4,4′-dialkoxy-2,2′-bipyrroles

The structure and the electrochemical and spectral properties of two conductive electrochemically polymerized substituted bipyrroles 4,4′-methoxy-2,2′-bipyrrole and 4,4′-buthoxy-2,2′-bipyrrole were studied and compared. The polymers were characterized by cyclic voltammetry, FT-Raman spectroscopy, scanning electron microscopy, and in situ conductivity measurements at different pH and redox state.     

Toxicokinetics and metabolic study of 2,2′-dihydroxy-4,4′- dimethoxybenzophenone

2,2′-Dihydroxy-4,4′-dimethoxybenzophenone (UV-D) is one of the benzophenones, which is widely used as UV filter to protect industrial and commercial products from light. This compound is suspected as a kind of endocrine-disrupting chemical, which might interfere with hormonal signaling pathways, and have potential adverse effects on human health. Thus, toxicity and metabolism of it could be important to know its biological effect. As little is known about the toxicokinetics and metabolism of UV-D, herein, the related study was performed on rats by orally administrating with UV-D. UV-D was found to be promptly metabolized to five main metabolites, which were further identified by high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry. Demethylation, hydroxylation, sulfonation, and glucuronidation were the main metabolic pathways for UV-D.     

Cotton-mouton constants and spatial structure of 2,2′- and 4,4′-dipyridyls and their salts in solutions

Magnetic birefringence has been used in studying the spatial structure of a series of dipyridyl derivatives in hydrochloric acid solutions, and also some of their quaternary salts in water. It has been shown that when the change is made from the molecular forms of the 2,2- and 4,4-dipyridyls to their protonated mono and bis derivatives, the angles of rotation of the aromatic rings are very little changed; in the methylated cation, the degree of acoplanarity increases.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2771–2775, December, 1991.     

Improved Synthesis of 4,4′-Disubstituted-2,2′-Bipyridines

Ruthenium(II) tris(2,2′-bipyridine) complexes show interesting photochemical properties^1. Complexes containing substituents in the 4-and 4′-position of the 2,2′-bipyridine ligand have recently been used in systems which are aimed at the conversion and storage of solar energy^2,3. 2,2′-Bipyridine has a long history as a metal-chelating agent⁴. The use of 4,4′-disubstituted bipyridines as metal-chelating agents so far has been restricted probably because the reported syntheses of these compounds are rather laborious and the yields are low or moderate^5–8.     

Features of condensation of 4,4′-Dihydroxybiphenyl with phenylphosphonous tetraethyldiamide

4,4′-Dihydroxybiphenyl was condensed with phenylphosphonous tetraethyldiamide. The moleccular mass, chemical composition, and structural features of the product, oligo(4,4′-biphenylene phenylphosphonite), were elucidated using the method of matrix-activated laser desorption/ionization, with a time-of-flight (TOF) mass analyzer. The oligophenylphosphites containing labile P-N bond, which are unstable under conditions of recording mass spectra, were stabilized by conversion into oligophenylphosphonates. 1H-Tetrazole catalyzes the reaction of phenylphosphonous tetraethyldiamide with 4,4′-dihydroxybiphenyl. Cross-linking in the solid state of the oligo(4,4′-biphenylene phenylphosphonite) containing terminal phosphonamidite group leads to gradual increase in the molecular weight and is accompanied by redox processes.     

Synthesis and properties of 2,2′-dipyridyl and 4,4′-dipyridyl complexes with thulium salts

Summary New complexes of 2,2-dipyridyl and 4,4-dipyridyl with thulium salts TmX ₃ (whereX=Cl^–, Br^–, NO ₃ ^– , NCS^–, and ClO ₄ ^– ) have been prepared and their solubilities in water at 21 °C were determined. The IR spectra of these compounds are discussed. The conditions of thermal decomposition of the complexes were also studied.

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Synthese und Eigenschaften von 2,2-Dipyridyl- und 4,4-Dipyridylkomplexen mit Thuliumsalzen

Zusammenfassung Es wurden neue 2,2-Dipyridyl- und 4,4-Dipyridyl-Komplexen mit Thuliumsalzen TmX ₃ (X=Cl^–, Br^– No ₃ ^– , NCS^–, ClO ₄ ^– ) dargestellt und ihre Wasserlöslihkeit bei 21 °C bestimmt. Die IR-Spektren werden diskutiert. Das thermische Verhalten der erhaltenen Komplexe wurde untersucht.

     

In situ synthesis and structure of FeCl4(4,4′-diethyl-4,4′-bipyh) (bipy = bipyridine)

A novel viologen(4,4′-bipyridinium)-based compound FeCl₄(4,4′-diethyl-4,4′-bipyH) (1) (bipy = bipyridine), in which 4,4′-diethyl-4,4′-bipyH (MQ ⁺) was generated in situ, is synthesized via the hydrothermal reaction and structurally characterized by single crystal X-ray diffraction. The crystal structure analysis reveals that the title compound features an isolated structure based on 4,4′-diethyl-4,4′-bipyH moieties and an iron atom terminally bound by four chlorine atoms. The 4,4′-diethyl-4,4′-bipyH moieties and (FeCl₄)^? anions are interconnected by hydrogen bonds to form a 3D supramolecular framework.     

Kinetic analysis of the mechanochemical syntheses of dialkyl 2,2′-bipyridyl-4,4′-dicarboxylate complexes of palladium

Kinetic models for the ‘molecular’ mechanochemical syntheses of α- and β-dialkyl 2,2′-bipyridyl-4,4′-dicarboxylate complexes of palladium (PdLⁿI₂, where n specifies the number of carbons in the alkyl chain of the ligand and α and β refer to the substitution of the alkyl chain) are explored. The Johnson–Mehl–Avrami–Yerofeev–Kolmogrov (JMAYK) model was determined to best fit the data obtained via ¹H NMR spectroscopic analysis of the reaction mixtures over time. A rate enhancement, and corresponding increase in the Avrami exponent, was observed when the complex formed was liquid crystalline at milling temperatures.     

Facile Synthesis of 2,2′‐Dialkylated 4,4′‐Oxybiphenols

2,2′‐Alkyl‐disubstituted 4,4′‐oxybiphenols (4) were prepared in good yields through esterification of 4,4′‐oxybiphenol (1), AlCl₃‐promoted Fries rearrangement, and AlCl₃/NaBH₄‐promoted reduction reaction.     

Raman spectrum of 1,1′-diethyl-2,2′-cyanine iodide near the π-π* electronic transition

The Raman spectrum of 1,1′-diethyl-2,2′-cyanine iodide in a methyl alcohol solution (4 × 10⁻⁵m) in which the lines of the argon ion laser at 457.9, 488.0, 496.5, 501.7 and 514.5 nm were employed as excitation sources has been investigated. The strongest lines in the Raman spectrum appear in the region from 1200–1700 cm⁻¹ and are strongly polarized (ϱ= 0.2). Two vibrational modes have been identified with reasonable certainty: one a doublet at 1361 and 1380 cm⁻¹ which involves the stretching of the conjugated chain in the ring of the quinolinic end groups, and the other at 1639 cm⁻¹ which characterizes the stretching of the conjugated chain which bridges the quinolinic end groups. The splitting of the line associated with the ring stretching mode probably arises from the resonance interaction between the two quinolinic end groups. The intensity and polarization of the lines in the spectrum indicate that the vibrational modes of the strongest lines are totally symmetric. The visible electronic spectrum shows maxima at 490.6 and 522.9nm; an analog resolution of the spectrum shows that the contour of the vibronic band can be accounted for by a vibronic progression with a spacing of approximately 1200 cm⁻¹. Both the observed variation of intensity and an approximate calculation based on A-term scattering of totally symmetric vibrational modes support the conclusion that a maximum enhancement of the intensity will be attained when the frequency of exciting radiation is equal to that of the pure electronic transition at 522.9 nm.     

Isolation and Crystal Structure of Trans-2,2′,4,4′-tetramethyl-6,6′-dinitro Azobenzene

Trans-2,2′,4,4′-tetramethyl-6,6′-dinitro azobenzene (C16H16N4O4, Mr = 328.32) was isolated from benzene extract of the leaves of Aconitum sungpanense Hand. Mazz. as a new compound, and characterized by spectral methods and X-ray diffraction analysis. It crystallizes in monoclinic system, space group P21/c with a = 8.544(1), b = 13.997(2), c = 7.161(1) A, β = 112.97(1), V = 788.4(2)A3, Z = 4, Dc = 1.383 g/cm3, F(000) = 344 and μ(MoKα) = 0.102 mm-1. The final R = 0.0395 and wR = 0.1140 for 1913 independent reflections with Rint = 0.0109 and 1329 observed reflections with I > 2((I). The molecule is composed of two phenyl rings through trans N=N.     

Synthesis and characterization of complexes of the first transition series cations with 2,2′-biimidazole and 2,2′-biimidazolate

Mononuclear [M(hfacac)₂(H₂biim)] complexes, where M = Mn^II, Fe^II, Co^II, Ni^II, Cu^II or Zn^II, hfacac = hexafluoroacetylacetonate, H₂biim = 2,2-biimidazole; dinuclear K₂[M₂(acac)₄(-biim)] (M = Cu^II or Zn^II) and tetranuclear K₂[M₄(acac)₈( ₄-biim)] (M = Co^II or Ni^II) complexes have been prepared and characterized by chemical analysis, conductance measurements, i.r., electronic and e.p.r. spectroscopies and by magnetic susceptibility measurements (in the 2–300 K range). Mn^II, Fe^II and Co^II are in a high spin state. The e.p.r. spectra of Cu^II and Mn^II compounds have been recorded.     

Thermodynamics of the solvation and phase distributions of 2,2′-dipyridyl in acetonitrile-DMSO-hexane and methanol-DMSO-hexane systems

The Gibbs energies of 2,2′-dipyridyl when transferred from dimethyl sulfoxide to its mixtures with acetonitrile and methanol are determined from the distribution of substance between immiscible phases. It is found that moving from dimethyl sulfoxide to acetonitrile and methanol weakens the solvation of 2,2′-dipyridyl due to a change in the solvation of amino groups and the hydrocarbon substituent, which is reflected in a reduction in the entropy component of the Gibbs energy.     

Heat capacity and thermodynamic functions of 4,4′-dimethylbiphenyl and 4,4′-di-tert-butylbiphenyl

The heat capacity (C _{p m} ) of 4,4′-dimethylbiphenyl and 4,4′-di-tert-butylbiphenyl in the temperature range of 8—373 K was measured by low-temperat ure adiabatic calorimetry, and thermodynamic characteristics of the solid-phase transitions of 4,4′-d i-tert-butylbiphenyl were determined. Temperatures, enthalpies, entropies of melting, and the purity of the samples of the tested substances were determined by means of differential scanning calorimetry. The main thermodynamic functions of the substances in the condensed state at 298 K were calculated.     

Diastereoselective aminocarbonylation of a steroidal iodoalkene with 2,2′-diamino-1,1′-binaphthalene in palladium-catalysed reactions

A palladium-catalysed aminocarbonylation of a steroidal iodoalkene (17-iodo-5α-androst-16-ene) model compound with 2,2′-diamino-1,1′-binaphthalene as an N-nucleophile was carried out. The combination of a steroidal skeleton possessing central elements of chirality and a binaphthyl moiety with axial chirality was carried out resulting in a novel type of steroidal carboxamides. The binaphthalene—steroid conjugates are potential 5α-reductase inhibitors. Both epimers of the monocarboxamide and those of the dicarboxamide, formed with moderate diastereoselectivity, were isolated and fully characterised.