Trisubstituted Benzene Derivatives Research Articles

New trisubstituted benzene derivatives bipolar host material for efficient blue electrophosphorescence

New trisubstituted benzene derivatives bipolar host material for efficient blue electrophosphorescence

Dimerization and cyclotrimerization of terminal arylalkynes initiated by a phosphine-free ruthenium alkylidene complex

Transformations of alkynes are of great importance in organic synthesis, including formation of natural compounds. Products of CC coupling of terminal alkynes, such as conjugated 1,3- or 1,4-enynes and tri-substituted benzene derivatives are key units of variety natural and biologically active products. Ruthenium catalysts can be effective for such synthesis, however, the mechanisms of these reactions are still not well understood. In this work, dimerization and cyclotrimerization of terminal arylalkyne (phenylacetylene) initiated by the third-generation Grubbs catalyst [RuCl2(CHPh)(3-Br-py)2(H2IMes)] have been theoretically and experimentally studied. It is shown that ruthenium vinylidene species might be the key intermediate in the catalytic cycle of phenylacetylene dimerization, whereas [RuCl2(H2IMes)] can be the active species in phenylacetylene cycylotrimerization. Ruthenium alkyne species [RuCl2(η2PhCCH)(H2IMes)] is a common intermediate for both competitive reactions. An overall mechanism for terminal arylalkyne transformations is proposed. It includes alkyne-induced decomposition of the phosphine-free ruthenium alkylidene catalyst via ruthenium vinylcarbene to ruthenium vinylidene and [RuCl2(H2IMes)], followed by the dimerization and cyclotrimerization reactions.

ChemInform Abstract: Synthesis of Symmetrical and Unsymmetrical Trisubstituted Benzene Derivatives Through Ring‐Closing Alkyne Metathesis Strategy and Depropargylation with Various Catalysts.

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Zeroing In on Electrophilic Aromatic Substitution

A unique and novel illustration of reactivity trends in the formation of trisubstituted benzene derivatives from disubstituted systems using electrophilic aromatic substitution reactions is presented. The reactivity trends of seven transformations involving eight electron-withdrawing groups and eleven electron-releasing groups of 1,2-, 1,3-, and 1,4-disubstituted benzene derivatives were confirmed after performing literature searches using SciFinder Scholar. The net results in the placement of the third substituent are governed by the electronic and steric effects of preexisting substituents.

Synthesis of Diverse Polycyclic Compounds via Catalytic Metathesis

A variety of olefin-metathesis protocols have been used to prepare spirocyclic compounds, cyclic sulfones, and constrained α-amino acid derivatives. Conceptually, a new approach to a novel cyclophane ring system has been realized via ring-closing meta-thesis (RCM). Also, tetracyclic compounds related to anthracycline antibiotics have been assembled using Claisen rearrangement and RCM as key steps. Further, a sequential use of the Diels-Alder -reaction and ring-opening cross-metathesis delivered highly functionalized spiroindane derivatives, and trisubstituted benzene derivatives have been assembled using Grubbs’ catalyst. Finally, the enyne and cross-enyne metathesis sequences have been used to prepare several constrained α-amino acid derivatives. 1 Introduction 2 Application of Ring-Closing Metathesis To Give Spiro-cyclic Compounds 3 Application of Ring-Closing Metathesis To Give Cyclophane Derivatives 4 Application of Ring-Closing Metathesis To Give Cyclic Sulfone Derivatives 5 Application of Ring-Closing Metathesis To Give Cyclic α-Amino Acid Derivatives and Modified Peptides 6 Application of Ring-Closing Metathesis to Benzannulation 7 Application of Enyne Metathesis to the Synthesis of Constrained α-Amino Acid and Naphthoxepin Derivatives 8 Application of Cross-Enyne Metathesis to the Synthesis of Highly Functionalized Phenylalanine Derivatives 9 Application of Ring-Opening Cross-Metathesis to Spiro-indanes 10 Synthesis of Trisubstituted Benzene Derivatives Using Grubbs’ Catalyst 11 Metathesis of a Novel Enyne System 12 Macroheterocycles via Cross-Enyne and Ring-Closing Metathesis Cascade Reactions 13 Conclusions

Synthesis and Conformational Analysis of Novel Trimeric Maleimide Cross-Linking Reagents

Nine homotrifunctional cross-linking reagents are presented. Their synthesis and chemical properties as well as their characterization by classical mechanical conformational searching techniques is reported. Mixed Low Mode and Monte Carlo searching techniques were used to exhaustively sample the OPLS2005/GBSA(water) potential energy surface of trisubstituted cyclohexane and benzene derivatives of C3 symmetry. Geometric structure, molecular length, and hydrogen-bonding patterns were analyzed. Nonaromatic compounds exhibited exclusively chair conformations at low energies, with a preference for axial or equatorial arms depending upon the presence of additional ring substituent Me groups. Increasing chain length often resulted in overall shorter molecular length due to additional chain flexibility. These results were consistent with one- and two-dimensional temperature-dependent NMR studies.

Synthesis and inhibitory activity of benzoic acid and pyridine derivatives on influenza neuraminidase

Based upon the activity and X-ray crystallographic studies of tri-substituted benzene derivatives containing carboxylic acid, acetamido and guanidine groups, we investigated the effect of the fourth substituent to fulfill the fourth pocket of neuraminidase enzyme. The groups selected as fourth substituents were hydroxymethyl, hydroxyethyl, oxime and amino. These tetra-substituted benzene derivatives were synthesized and evaluated for neuraminidase inhibitory activity. All these compounds were found to have poorer IC 50 values than the tri-substituted compounds. Further, benzene ring was replaced by pyridine ring and di, tri and tetra-substituted pyridine derivatives were synthesized. The activity of the pyridine derivatives was comparable to benzene derivatives. The fourth substituent seems to disturb the binding of the other three substituents, so the activity is reduced as compared to tri-substituted benzene and pyridine derivatives.

Induced Mesophases in Binary Systems of Non-Mesogens Where One of the Component is 1,2,4 Trisubstituted Benzene Derivatives

Exhibition of mixed mesophases in binary systems where both the components are non-mesogens by themselves offer a very interesting study. In the present work four binary systems were studied where one of the components is non-mesogenic 1,2,4-trisubstituted benzene derivative while the other components are rod shaped non-mesogens. Induction of mesophases is observed in all the binary systems studied. Few compositions on cooling remain in liquid crystalline phase at the ambient temperatures for about 48 hours.

Mild ruthenium-catalyzed intermolecular alkyne cyclotrimerization

Grubbs' catalyst [(PCy 3) 2Cl 2RuCHPh, 7] was shown for the first time to be an effective catalyst for the mild intermolecular cyclotrimerization of terminal alkynes ( 1–6). The reaction is general and the isomeric trisubstituted benzene derivatives ( 8–13) were isolated in good to excellent yields.

Revised Substituent Entropy Constants .SIGMA.s.DEG. for Di- and Tri-Substituted Benzene Derivatives, and Their Applications for Substrates Having Two Substituted Phenyl Rings.

Revised Substituent Entropy Constants .SIGMA.s.DEG. for Di- and Tri-Substituted Benzene Derivatives, and Their Applications for Substrates Having Two Substituted Phenyl Rings.

Estimation of the quantitative structure-activity relationship descriptor .SIGMA.S.DEG. for di- and tri-substituted benzene derivatives.

The quantitative structure-activity relationship descriptor sigma S0, representing the contributions from dispersion and repulsion interactions can be expressed as follows: (1) for disubstituted benzene derivatives, sigma S0(1, 2) = 0.831 sigma sigma S0(mono) - 0.004, sigma S0(1, 3) = 0.855 sigma sigma S0(mono) - 0.007, and sigma S0(1, 4) = 0.874 sigma sigma S0(mono) - 0.018; (2) for trisubstituted benzene derivatives, sigma S0(1, 3, 5) = 0.752 sigma sigma S0(mono) - 0.017, sigma S0(1, 2, 4) = 0.715 sigma sigma S0(mono) + 0.006, and sigma S0(1, 2, 3) = 0.723 x sigma sigma S0(mono) - 0.006. These are revealed to be successful for the estimation of the descriptors sigma S degrees for optional di- and tri-substituted benzene derivatives, and meet the needs of the practical qualitative structure-activity relationships.

Determination of the novel quantitative structure-activity relationships descriptor .SIGMA.S.DEG. for di- and trisubstituted benzene derivatives.

For di-and trisubstituted benzene derivatives, the novel quantitative structure-activity relationships descriptors σS°, representing both dispersion and repulsion interaction energies, have been successfully determined from the linear relations of the observed absolute entropy S°298(g) for the above series against those of monosubstituted benzene derivatives, Unknown values of S°298(g) could be estimated statistically by inter- or extrapolation of the linear relations, and numerous kinds of descriptors, σS° for ortho-, meta-, para-disubstituted benzene derivatives, together with those of the trisubstituted series, having the same kind of substituent, have been presented.Their validities are supported by the results of evaluation of the gas liquid chromatography relative retention value logγ for disubstituted benzene derivatives.

5-Nitro-2-furylvinylation of substituted benzene derivatives

5-Nitro-2-furylvinylation of o-, m-, and p-disubstituted and trisubstituted benzene derivatives afforded under conditions of Friedel-Crafts condensation (E)-2-substituted 1-(5-nitro-2-furyl)-ethylene.

Synthesis of symmetrically trisubstituted benzene derivatives

Syntheses are described of 1,3,5-trisubstituted benzenes with the following substituents CH2Cl, CH2OEt, CH2OBz, and [CH2]2X (X = OH, OAc, OCBz, Cl, Br, CN, or CO2H), an improved route to 1,3,5-tris(hydroxymethyl)-benzene and alternative routes to the corresponding tri-aldehyde and tris(bromomethyl) derivative.

On the superimposability of the electronic spectra of disubstituted benzene derivatives in the interpretation of the principal absorption bands of certain trisubstituted derivatives

AbstractThe validity of a superimposability principle for the electronic spectra of disubstituted benzene derivatives, proposed by Doub and Vandenbelt5 to interpret the principal absorption bands of some trisubstituted benzene derivatives is discussed for p‐aminosalicylic acid, β‐resorcylic acid and 2‐amino‐5‐chlorobenzoic acid.

LIGHT ABSORPTION STUDIES: PART III. STRUCTURE AND LIGHT ABSORPTION OF TRISUBSTITUTED BENZENE DERIVATIVES

The spectra of a number of trisubstituted benzene derivatives which have recently been described by Doub and Vandenbelt are discussed in terms of the electronic and steric effects. The assumption of Doub and Vandenbelt, that the steric effects are usually small in absorption spectra, is criticized.

CLXXVII.—Substitution in vicinal trisubstituted benzene derivatives. Part I

CLXXVII.—Substitution in vicinal trisubstituted benzene derivatives. Part I