Liquid crystals of some new tolane derivatives containing a 1,2-ethylene linkage

Abstract

Three types of nematogenic compound, 4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-alkyltolanes, 2-fluoro-4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-alkyltolanes and 4-[2-(trans-4-alkylcyclohexyl)ethyl]-4′-halogenotolanes, have been synthesized and their transition temperatures and enthalpies determined. Their bulk viscosity and birefringence have been estimated from those of mixtures with other liquid-crystalline compounds. These compounds have been found to be excellent materials for twisted nematic displays, because of their wide nematic temperature range, high birefringence (Δn = 0·26), and low viscosity (η = 21 cP at 20°C). Several related compounds having other central linkages, namely -CH₂O-, a single bond or -COO-, in place of the 1,2-ethylene group, have also been studied.     

Optically active heteroaromatic compounds IX. Preparation,absolute configuration and optical purity of some chiral 3-alkylindoles

The Fischer and Brunner reactions as well as the Grignard alkylation of isatin have been used to prepare (S)-3-sec-butyl- and (S)-3-(2-methylbutyl)indoles, respectively, starting from (S)-1-chloro-2-methylbutane. The stereospecificity of the synthetic sequences followed has been investigated and the stereochemical relationships of the title compounds have been established.     

Electron impact induced cyclizations in 4-chioro-3-(N-aryliminomethyl) (2H) benzopyrans and benzothiopyrans

Intramolecular substitutions leading to cyclizations with the ejection of chlorine have been noticed during mass spectral fragmentation of 4-chloro-3-(N-aryliminomethyl) (2H) benzopyrans and benzothiopyrans. Very interesting ortho effects involving intramolecular substitutions have also been observed in 6-methyl-4-diloro-3-[N-(2-methoxyphenyliminomethyl)] (2H) benzopyran and 6-methyl-4-chloro-3-[N-(2-chlorophenyliminomethyl)]-(2H) benzopyran. The proposed fragmentation mechanisms have been supported by the accurate mass measurements and linked scan studies.     

Synthesis of imidazo[4,5-b]- and [4,5-c]pyridines

2-Arylimidazo[4,5-b]- and [4,5-c]pyridines have been prepared by treatment of the appropriate 2,3- or 3,4-diaminopyridine with an aromatic carboxylic acid in the presence of polyphosphoric acid. Other derivatives have been prepared by similar cyclisation of diaminopyridines using triethyl orthoformate, urea, thiophosgene and thiourea and the properties of some N-oxides have been investigated. A number of the arylimidazopyridines have been screened for mutagenicity.     

Reaction of chlorosulfonyl isocyanate with aziridines

The reaction of chlorosulfonyl isocyanate (CSI) with 1,2,3-triphenylaziridine (1) and some cis- and trans-1-cyclohexyl-2-aroyl-3-phenylaziridines, 4-7 and 19-22 has been described. The cis-isomers of aziridines, 4-7 , undergo a smooth reaction with CSI to give the corresponding cis-isomers of 2-chlorosulfonylimino-1,3-oxazolidines, 8-11 , in good yields (65-67%). While the trans-isomers, 19-22 , gave unusual products 23-26 which have been assigned a bicyclic structure, based on their physical and spectral (ir, pmr, ms) data. Plausible mechanisms have been postulated to explain the transformations.     

1H-NMR,Ultraviolet and infrared spectra of some (Z)-α-(phenyl)-β-(2-furyl), -(2-pyrrolyl) and -(N-methyl-2-pyrrolyl)acrylonitriles

The ¹H-nmr data of some (Z)-α-(p-substituted-phenyl)-β-(2-furyl), -(2-pyrrolyl), and -(N-methyl-2-pyrrolyl)-acrylonitriles have been investigated to indicate the preferred conformation and to establish the conformational preferences of the β-heterocyclic ring. The ultraviolet spectra have been discussed in order to obtain information about the chromophores responsible for the absorption. The infrared spectra have been analyzed for the identification of the main absorption frequencies of cyano and ethylenic groups and to assign the characteristic absorption bands to specific normal vibrations of the heteroaromatic nuclei.     

SYNTHESIS AND SPECTROSCOPIC STUDIES OF Cu(II) COMPLEXES OF SOME LIGANDS CONTAINING THE AMIDE GROUP

Abstract

Complexes of Cu(II) with N-(2′-carboxyphenyl)benzamide (CPBH), 2-amino-N-(2′-carboxyphenyl)benzamide (ACPBH), isoxazolylbenzamine (IB), N-anilinobenzamide (AB), N-(2-pyridyl)-3-carboxypropanamide (PCPAH) and N-(2-pyridyl)-2-carboxybenzamide (PCBAH) have been prepared and characterized by analyses, magnetic susceptibility measurements, thermal studies and I. R., electronic and EPR studies. Visible and E. P. R. spectra indicate that the complexes are monomeric, having either square planar or distorted octahedral geometry. Interesting amide bonding patterns have been observed and various E. P. R. parameters have been evaluated.     

Synthesis, characterization, and biological activities of some transition metal(II) complexes with the thiosemicarbazone derived from 4-[1-(4-methylphenylsulfonyl)-1H-indol-3-yl]but-3-en-2-one

A new 4-[1-(4-methylphenylsulfonyl)-1H-indol-3-yl]but-3-en-2-one thiosemicarbazone (HL) was synthesized derived from 4-[1-(4-methylphenylsulfonyl)-1H-indol-3-yl]but-3-en-2-one. Four transition metal(II) complexes of HL have been prepared. Elemental analysis, molar conductivity, IR, UV, ¹H NMR spectra, and TG-DTA have been used to characterize these complexes. The complexes have the general formula ML₂, where M = Zn, Cu, Co, and Ni. The ligand and its complexes have been studied for their possible biological activity including anti-inflammatory, antibacterial, and antitumour activity in vitro.     

Synthesis and Characterization of Oxybis(Diacetoxyborane) Derivatives of Bifunctional Tridentate Aldimines

The reactions of oxybis(diacetoxyborane) with the aldimines, N-(2-hydroxyethyl) salicylaldimine N-(2-hydroxy-1-propyl) salicylaldimine, N-(3-hydroxy-1-propyl) salicylaldimine, N-(o-hydroxyphenyl) salicylaldimine. N-(m-hydroxyphenyl) salicylaldimine, N(2-hydroxyethyl)-2-hydroxy-1-naphthaldimine and N(2-hydroxy-1-propyl) 2-hydroxy-1-naphthaldimine have been carried out in 1: 1 and 1: 2 molar ratios. All the compounds except those derived from N-(3-hydroxy-1-propyl) salicylaldimine have been found to be sparingly soluble in benzene and nonelectrolytes in anhydrous DMF. The newly synthesized derivatives have been characterized by elemental analysis, molecular weight determinations and infrared, proton magnetic resonance, ultraviolet, visible and ¹¹B nuclear magnetic resonance spectral studies.     

Volumetric Properties of Sodium Nitrobenzoate in <Emphasis Type="Italic">N</Emphasis>, <Emphasis Type="Italic">N</Emphasis>-Dimethylformamide–Water Mixtures at 298.15 K

Densities of sodium nitrobenzoate (o-, m-, p-) have been measured in dimethylformamide (DMF)–water mixtures at 298.15 K with an oscillating-tube densimeter. From these densities, apparent molar volumes of sodium nitrobenzoate in DMF–H₂O-mixtures have been calculated and partial molar volumes at infinite dilution have been evaluated. Substituent and solvent effects on the transfer volumes of each isomer from water to DMF–H₂O-mixed solvents have also been obtained. The results are explained in terms of solvent–solvent and solute–solvent interactions.     

Structural studies on new diphenyl formazans and their lanthanide(III) complexes

Summary Potentiometric, u.v., i.r., n.m.r. and t.g.a. studies have been carried out on 1,5-bis(o-carboxyphenyl)-3-acetyl-formazan and 1-(o-carboxyphenyl-5-(o-hydroxyphenyl)-3-acetylformazan and their complexes with trivalent lanthanide ions. The ionization constants of formazans and the formation constants of their complexes have been determined potentiometrically by the Bjerrum-Calvin method (Irving and Rossotti modification). Complexation has also been studied by a conductimetric titration method.     

Force field calculations (MM3) on glyoxal,quinones, and related compounds

A general force field type of calculation has been devised in connection with MM3 to treat 1,2- and 1,4-diketones, both when they are not conjugated (as in derivatives of glyoxal) and when they are conjugated (as in derivatives of ortho- and para-benzoquinone). The molecular structures, moments of inertia, dipole moments, and vibrational spectra have been examined for about 15 compounds, some in several conformations. Ab initio calculations (6-31G*) have been used to determine quantities that have not been previously defined by experiment. In general, the force field permits the calculation of the structures with high accuracy, and the spectroscopic and conformational energy data with fair accuracy. © 1994 by John Wiley & Sons, Inc.     

New isomeric N-substituted hydrazones of 2-, 3-and 4-pyridinecarboxaldehydes

Eighteen compounds unknown in the literature, N-(E)-stilbenyloxyalkylcarbonyl- and N-(E)-stilbenyloxyalkylcarbonylaminoalkylcarbonyl-substituted hydrazones of 2-, 3- and 4-pyridinecarboxaldehydes have been prepared. The stereochemical behavior of these compounds in dimethyl-d₆ sulfoxide solution has been studied by ¹H-nmr technique. The E geometrical isomers and cisltrans amide conformers have been found for N-substituted-hydrazones 1–16 .     

Synthesis of some new fluorine containing 3-dialkylaminomethyl indoles, 3-indolylglyoxamides and tryptamines

Several new 2-(fluoroaryl)-3-dialkylaminomethylindoles, 3-acetyl-2-(fluoroaryl)-indoles, 2-(fluoroaryl)-3-indolylglyoxamides and corresponding tryptamines have been prepared as possible psychopharmacological agents. 2-(Fluoroaryl)-indoles have been synthesized by theFischer indole synthesis. 2-(Fluoroaryl)-indoles on treatment with oxalyl chloride and subsequent reaction with amines, gave 2-(fluoroaryl)-3-indolylglyoxamides. Some of these indolylglyoxamides were reducted with lithium aluminium hydride, to the corresponding tryptamines. 2-(Fluoroaryl)-indoles when subjected toMannich reaction afforded 3-dialkylaminomethyl-2-(fluoroaryl)-indoles. All these new compounds have been characterized by IR spectral studies.Possible Psychopharmacological Agents, Part XII, Part XI, J. Indian. Chem. Soc.57, 423 (1980).     

Nickel(II) complexes of N-(dialkylcarbamothioyl)-4-nitrobenzamide as single-source precursors for the deposition of nanostructured nickel sulfide thin films by chemical vapor deposition

Nickel(II) complexes of N-(di-alkyl-carbamothioyl)-4-nitrobenzamide (alkyl?=?ethyl or n-propyl) have been synthesized and characterized by infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry. The structures of bis[N-(diethylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2a) and bis[N-(dipropylcarbamothioyl)-4-nitrobenzamide]nickel(II) (2b) have been determined by X-ray crystallography. FTIR and NMR of the nickel complexes showed the absence of the N–H proton resonance and the N–H stretch and shift of ν _C=O and ν _C=S as expected. Both complexes have been used as single-source precursors for the deposition of nickel sulfide nanostructured thin films by aerosol-assisted chemical vapor deposition. The nanostructured thin films were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray analysis, and atomic force microscopy.     

Molecular dynamics of (Z)-1-(2-hydroxy-5-methyl-3-nitrophenyl)ethanone oxime and (E)-2-hydroxy-5-methylacetophenone thiosemicarbazone in solution studied by NMR spectroscopy

The formation of hydrogen bonds and the molecular dynamics for molecules (Z)-1-(2-hydroxy-5-methyl-3-nitrophenyl)ethanone oxime and (E)-2-hydroxy-5-methylacetophenone thiosemicarbazone, (E)-4-bromoacetophenone thiosemicarbazone have been investigated in solution using NMR. The results confirm the formation of different O-H…O type intramolecular hydrogen bonds in the oxime molecule. The rotational barrier energy and energy of intramolecular hydrogen bonds have been determined.     

Myrochromanol und Myrochromanon,zwei weitere Metaboliten von Myrothecium roridum Tode ex Fr. Verrucarine und Roridine, 25. Mitt.

From cultures of Myrothecium roridum Tode ex Fr. myrochromanol ( 1 ) and myrochromanone ( 3 ), two new substituted chromanes, have been isolated. Their structures as 2-(1-propenyl)-4-hydroxy-6-methyl-chromane and 2-(1-propenyl)-4-oxo-6-methyl-chromane respectively, have been determined using spectroscopic techniques and by degradation to 2-hydroxy-5-methylbenzoic acid ( 6 ). The stereochemistry of 1 and 2 is deduced by NMR., CD. and by partial resolution ( Horeau method).     

The absolute configuration of 3-phenylpyrrolidine

(+)-3-Phenylpyrrolidine and (+)-phenylsuccinic acid have been chemically correlated through (-)-N-benzyl-3-phenylpyrrolidine. All these compounds have an S absolute configuration.     

Resolution of enantiomers and isotopic compositions by selective complexation gas chromatography on metal complexes

Summary The high selectivity of complexation gas chromatography has been employed for enantiomer resolution and isotope separation. Thus, a chiral olefin, 3-methylcyclopentene, has been resolved analytically on optically active dicarbonyl-rhodium(I)-3-trifluoroacetyl-1R-camphorate in squalane. The deuterated ethylenes C₂H_4–nD_n have been separated on the same rhodium(I)-containing stationary phase. The chiral aliphatic oxiranes epoxypropane andtrans-2,3-epoxybutane have been resolved on optically active nickel(II)-bis-3-trifluoroacetyl-1R-camphorate in squalane.