Calorimetric study of 2′-methylacetophenone and 4′-methylacetophenone

Values of the condensed phase standard (p = 0.1 MPa) molar enthalpy of formation for 2′- and 4′-methylacetophenones were derived from the standard molar energies of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The values of the standard molar enthalpy of vaporization, at T = 298.15 K, were measured by Calvet microcalorimetry. Combining these two values, the following enthalpies of formation in the gas phase, at T = 298.15 K, were then derived: 2′-methylacetophenone, –(115.7 ± 2.4) kJ · mol⁻¹, and 4′-methylacetophenone, –(122.6 ± 2.4) kJ · mol⁻¹. Substituent effects are discussed in terms of stability and compared with other similar compounds. The value of the standard molar enthalpy of formation for 3′-methylacetophenone was estimated from isomerization schemes.     

Syntheses and Crystal Structures of 4,4′Diformyl-diphenoxyethane and 4,4′4′′-Triformyl-triphenoxytriethylamine

1 INTRODUCTION With the methods of [2+3] and [1+1] tripodal condensation of polyaldehyde with polyamine, many Schiff bases and their relative reduced polyaza cryptands have been facilely synthesized in high yields[1～5]. In this one-step route, some metal ions such as alkali[2, 6, 7], alkali earth[8], rare earth[9, 10] and other transition ions[4, 11, 12] were used as templates[13, 14]. Formerly, the dialdehydes are needed to be rigid structures[15] to prevent themselves from polymeri…     

Synthesis of Phosphorylated Derivatives of Sucrose: 6,6′-di-Phosphonate, 6- and 6′-Phosphonates,and 6,6′-di-Phosphine

Reaction of 6,6′dideoxy-6,6′di-iodo-1′,2,3,3′,4,4′-hexa-O-benzylsucrose with triethyl phosphite afforded the corresponding 6,6′-diphosphonate. Selective phosphonylation either at the C-6 or 6-6′ position was also possible providing the corresponding sucrose mono-phosphonates. Reaction of 6,6′-dichloro-hexa-O-benzylsucrose with diphenylphoshine anion afforded the 6,6′-diphosphinosucrose.     

Experimental and theoretical investigations of absolute stereochemistry and chiroptical properties of enantiopure 2,2′-substituted 9,9′-bianthryls

The absolute stereochemistry of axially chiral 2,2′-X₂-9,9′-bianthryls (X=COOH, COOMe, and Cl) was determined by X-ray analysis of the (+)-quinidine salt of the diacid to be (M)-(−) or (P)-(+). The M isomers of these compounds showed specific rotations of −115, −123, and −32, respectively, in acetone. The circular dichroism (CD) as well as UV spectra of the two M isomers (X=COOMe and Cl) were investigated with the aid of theoretical calculations by the time-dependent DFT (TDDFT) method. The calculations reasonably reproduced the observed CD bands, and suggested a correlation between the signs of p or β′ bands and the absolute stereochemistry.     

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.

---

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.

     

Diastereoselective and enantioselective synthesis of 4′-aza analogues of 2′,3′-dideoxynucleosides

A diastereo- and enantioselective synthesis of 4′-aza analogues of 2′,3′-dideoxynucleosides has been designed by the strategy of the 1,3-dipolar cycloaddition reaction of a Vasella-type nitrone. The reaction leads to (1′R)- and (1′S)-4′-aza analogues of 2′,3′-dideoxythimidine and fluorouridine, in enantiomerically pure forms.     

Synthesis of 5′-benzoyl-2′-hydroxychalcones and related flavonoid compounds

Summary 5 -Benzoyl-2 -hydroxychalcones were synthesized by the condensation of 5 -benzoyl-2 -hydroxyacetophenone with aromatic aldehydes in presence of an ethanolic solution of potassium hydroxide. Derivatives of 6-benzoylflavonoids were prepared from chalcones.     

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.     

Synthesis and Crystal Structure Analysis of 5′-O-Tosyl-2,3′-anhydrothymidine

In this paper=5′-O-tosyl-2,3′-anhydrothymidine has been synthesized and its crystal structure was analyzed. The crystal belongs to the triclinic system=space group P1=with a=5.397(2)=b=6.1886(18)=c=3.507(5) =α =87.74(2)=β =89.84(4)=γ =73.79(2)°=C17H18N2O6S=Mr=378.39=Z=1=V=432.8(3)3=Dc=1.452 g/cm3=F(000)=198 and Flack =-0.11(14). No intermolecular hydrogen bonds exist in the crystal=and the angle between benzene ring and pyrimidine planes is 32.23°.     

Spectroscopic and electrochemical properties of cyclopalladated complexes of 2,3-diphenylquinoxaline and 2,2′,3,3′-tetraphenyl-6,6′-biquinoline

Comparative study of cyclopalladated ethylenediamine complexes of 2,3-diphenylquinoxaline (Hdphqx) [Pd(dphqx)En]ClO₄ and 2,2′,3,3′-tetraphenylbiquinoline (H₂tphbq) [(PdEn)₂(μ-tphbq)](ClO₄)₂, and the free heterocyclic ligands was performed by means of ¹H NMR spectroscopy, electronic absorption and emission spectroscopy, and cyclic voltammetry. It was shown that cyclopalladation gives rise to a long-wave absorption band in the visible spectrum, a batochromic shift of the vibrationally structured phosphorescence band, and an anodic shift of the ligand-centered reduction potential of the complexes com-pared to free ligands.     

Synthesis and protonation of 2,3′-biquinolyl dianions

It has been shown that the reaction of 2, 3-biquinolyls with an excess of lithium in tetrahydrofuran leads to the formation of dianions, treatment of which with water or D₂O gives 1, 4-dihydro-2, 3-biquinolyls or their 4-D derivatives in good yield. Oxidation of the latter leads to 4-D-2,3-biquinolyl. The reduction of 2, 3-biquinolyl has been studied.Stavropol State University, Stavropol 355009. Rostov State University, Rostov-on-Don 344090. Russian University of Chemical Technology, Moscow 125190. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1391–1394, October, 1996. Original article submitted September 10, 1996.     

Synthesis and antimycobacterial activity of N-isonicotinoyl-N′-alkylideneferrocenecarbohydrazides

Russian Chemical Bulletin - Acylation of ferrocenoylhydrazones with isonicotinoyl chloride hydrochloride in pyridine was used to obtain a number of new...     

Resolution and determination of the absolute configuration of 3,3′4,4′-tetramethyl-1,1′-diphosphaferrocene-2-carboxylic acid

(±)-3,3′4,4′-Tetramethyl-1,1′-diphosphaferrocene-2-carboxylic acid 1 was resolved via diastereomeric salts with brucine. The (R)-absolute configuration of (+)-1 was determined by X-ray crystallography.     

Synthesis of 3′-deoxy-3′-iminodiacetic acid and 3′-deoxy-3′-aminodiethanol thymidine analogues and NMR study of their complexation with boronic acids

The iminodiacetic acid and aminodiethanol moieties are known for their ability to generate with boronic acids bicyclic structures having a strong intramolecular NB coordination. We describe here the convergent synthesis of 3′-deoxy-3′-iminodiacetic acid and 3′-deoxy-3′-aminodiethanol thymidine analogues. The abilities of these compounds to form boronate complexes with aliphatic or aromatic boronic acids were established by 1D and 2D ¹H and ¹³C NMR. Moreover, conformational analysis of the newly synthesized compounds revealed a marked preference for an N-type sugar puckering.     

Synthesis of 2-O-ethyl analogues of 3′-azido- and 3′-fluoro-2′,3′-dideoxyuridines and evaluation of their biological activity against HIV

Summary 2-O-Ethyluracil and 2-O-ethylthymine were silylated with 1,1,1,3,3,3-hexamethyldisilazane and condensed in the presence ofTMS triflate with 2,3-dideoxy-3-fluoro-D-erythro-pentofuranoside, 3-azido-2,3-dideoxy-D-erythro-pentofuranoside, and 2,3-dideoxy-3-phthalimido--D-erythro-pentofuranose derivatives to give the corresponding 2-O-ethyl nucleosides. Deprotection with saturated methanolic ammonia afforded the 2,3-dideoxy-3-fluoro-2-O-ethyluridines, whereas 3-azido-2,3-dideoxy-3-O-ethyluridine was obtained by deprotection with tetrabutylammonium fluoride in tetrahydrofuran. 3-Amino-2,3-dideoxy-3-O-ethyluridine could be obtained only by treatment of the corresponding 3-azido nucleoside with triphenylphosphine in pyridine. 3-Deoxy-2-O-ethyl-3-fluorothymidine (6b) showed moderate activity against HIV-1.

---

Synthese von 2-O-Ethyl-Analogen von 3-Azido- und 3-Fluor-23-dideoxyuridinen und Bestimmung ihrer biologischen Aktivität gegenüber HIV

Zusammenfassung 2-O-Ethyluracil und 2-O-Ethylthymin wurden mit 1,1,1,3,3,3-Hexamethyldisilazan silyliert und in Gegenwart vonTMS-triflat mit 2,3-Dideoxy-3-fluoro-D-erythro-pentofuranosid, 3-Azido-2,3-dideoxy-D-erythro-pentofuranosid und 2,3-Dideoxy-3-phthalimido--D-erythro-pentofuranosederivaten zu den entsprechenden 2-O-Ethyl-Nucleosiden umgesetzt. Entfernung der Schutzgruppe mit gesättigter methanolischer Ammoniaklösung lieferte 2,3-Dideoxy-3-fluor-2-O-ethyluridin; 3-Azido-2,3-dideoxy-3-O-ethyl-uridin wurde durch Entschützung mit Tetrabutylammoniumfluorid in Tetrahydrofuran erhalten. 3-Amino-2,3-dideoxy-3-O-ethyl-uridin konnte nur durch Behandeln des entsprechenden 3-Azido-Nucleosids mit Triphenylphosphin in Pyridin hergestellt werden. 3-Deoxy-2-O-ethyl-3-fluor-thymidin (6b) zeigt geringe Aktivität gegenüber HIV-1.

     

The crystal and molecular structures of 1,1′-divinyl-2,2′-biimidazolyl

The crystal and molecular structures of 1,1-divinyl-2,2-biimidazolyl (L) were determined by x-ray crystallographic analysis. It was established that the molecule of L has crystallographic symmetry 2 and a cisoid conformation with an angle of rotation of 128° between the imidazole rings. The length of the C²-C² bond is increased to 1.485(11) Å compared with the length of the analogous bond in unsubstituted 2,2-biimidazolyl (1.423 Å). Localization of the N=C multiple bond is observed [1.297(9) Å]. The other N-C bonds of the ring are almost equalized (1.374 Å) and are close to the standard values for bonds of the C _sp ²-N type in imidazoles. The angle between the plane of the heterocycle and the plane passing through the atoms of the vinyl group amounts to 7°.N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 117907 Moscow. Irkutsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 664033 Irkutsk. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1376–1380, June, 1992.     

Resolution of 8′-alkoxy- and hydroxy-1,1′-binaphthalen-8-ols

Enantiopure 8′-ethoxy-, 8′-hydroxy-, and 8′-methoxy-1,1′-binaphthalen-8-ol were readily resolved by separating the corresponding chiral camphanic esters [derived from the esterification of the alcohols with (−)-(1S)-camphanic chloride] based upon their differing solubility in diethyl ether and their differing chromatographic behavior.