scholarly journals Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

2018 ◽  
Vol 14 ◽  
pp. 2384-2393
Author(s):  
Piotr Pomarański ◽  
Piotr Roszkowski ◽  
Jan K Maurin ◽  
Armand Budzianowski ◽  
Zbigniew Czarnocki
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
X Ray ◽  
H Nmr ◽  
Important Group ◽  
Cross Coupling Reaction ◽  
Efficient Access ◽  
Phenylboronic Acids ◽  
Derivatives Of ◽  
Single Bonds

Background: Atropisomers are very interesting stereoisomers having axial chirality resulting from restricted rotation around single bonds and are found in various classes of compounds. ortho-Substituted arylpyridines are an important group of them. A regio- and atropselective Suzuki–Miyaura cross-coupling reaction on 3,4,5-tribromo-2,6-dimethylpyridine was studied. Results: Reactions with various amounts of ortho-substituted phenylboronic acids with 3,4,5-tribromo-2,6-dimethylpyridine gave a series of mono- di- and triarylpyridine derivatives which allowed to draw conclusions about the order of substitution. Also, the observed selectivity in the case of ortho-methoxyphenylboronic acid suggested an additional metal O-chelation effect in the transition state, apparently not present in the ortho-chloro analogues. The rotational barrier in selected atropisomers was determined on the basis of HT NMR and thermal epimerisation experiments. The structure of most presented atropisomeric derivatives of 2,6-dimethylpyridine was confirmed by single-crystal X-ray analysis. Racemic chiral, differently substituted atropisomers were also examined by 1H NMR spectroscopy in the presence of a chiral solvating agent. Conclusion: This regio- and atropselectivity may be generally applicable to other arylpyridine systems. A regio- and atropselective Suzuki–Miyaura cross-coupling process has been observed, giving an efficient access to a class of atropisomeric compounds. An opposite selectivity using a differently ortho-substituted phenylbornic acid was observed.

scholarly journals Synthesis and Structure of (Nitronyl Nitroxide-2-ido)(tert-butyldiphenylphosphine)gold(I) and -(Di(tert-butyl)phenylphosphine)gold(I) Derivatives; Their Comparative Study in the Cross-Coupling Reaction

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 770
Author(s):  
Igor Zayakin ◽  
Irina Bagryanskaya ◽  
Dmitri Stass ◽  
Maxim Kazantsev ◽  
Evgeny Tretyakov
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Oxidation Potential ◽  
Nitronyl Nitroxide ◽  
X Ray ◽  
Tert Butyl ◽  
Cross Coupling Reaction ◽  
Vis Spectroscopy ◽  
The Cross ◽  
Derivatives Of

We synthesized two new organogold derivatives of a nitronyl nitroxide (NN) with phosphine ligands, namely NN-Au-PtBuPh2 and NN-Au-PtBu2Ph. They were characterized by X-ray diffraction analysis, cyclic voltammetry, and ESR, IR, and UV/Vis spectroscopy. The X-ray structural analysis revealed a tendency of the NN moiety to form a large number of short intermolecular contacts. This phenomenon is related to the anionic nature of the paramagnetic group NN, as evidenced by a significantly lower oxidation potential in comparison with purely organic derivatives of NN radicals. The cross-coupling reaction of NN-Au-PPh3, NN-Au-PtBuPh2, or NN-Au-PtBu2Ph with an activated bromoarene, namely, p-BrC6H4NO2, was investigated. It was shown that regardless of the presence of the bulky tert-butyl substituent, all gold derivatives have similar activities in the cross-coupling reaction and give a cross-coupling product, NN-C6H4NO2, with comparable yields.

scholarly journals Synthesis and Study of Chemical, Thermal, Mesomorphic, and Optical Properties of Terphenyls Modified with Nitrile Groups

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
M. L. Mota González ◽  
A. Carrillo Castillo ◽  
R. C. Ambrosio Lázaro ◽  
J. Flores Méndez ◽  
Mario Moreno ◽  
...  
Keyword(s):  
Optical Properties ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
H Nmr ◽  
Cross Coupling Reaction ◽  
Vis Spectroscopy

We report the synthesis, characterization, and the thermotropic and photoluminescence properties of dialkoxyterphenyls with (T12-CN and T12-2CN) and without (T12) nitrile groups. These terphenyls were prepared through the Suzuki-Miyaura cross-coupling reaction using a palladium-based catalyst. The products obtained were analyzed as powders or after being drop-casted or spin-coated on glass. Nuclear Magnetic Resonance (1H NMR) and Fourier Transform Infrared (FTIR) spectroscopy techniques confirmed the structure and purity of the synthesized terphenyls. The mesomorphic behavior was studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD). T12 developed various mesophases, whereas T12-CN and T12-2CN displayed one single mesophase of low order over a wide temperature range. The films topology was studied by AFM and the optical properties were determined by ultraviolet-visible (UV-Vis) spectroscopy and spectrofluorometry. Higher roughness was found for the films prepared with the asymmetric terphenyl (T12-CN). The photoluminescence (PL) spectrum obtained for the asymmetric terphenyl (T12-CN) exhibited the expected characteristics with an emission band centered at 381 nm and an overtone around 760 nm.

Synthesis of N- and B-Substituted Derivatives of closo-Amino-undecahydro-dodecaborate(1-) Anion

1997 ◽  
Vol 62 (8) ◽  
pp. 1185-1204 ◽  
Author(s):  
Bohumír Grüner ◽  
Bernard Bonnetot ◽  
Henri Mongeot
Keyword(s):  
Dimethyl Sulfate ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
The Novel ◽  
H Nmr ◽  
Palmitoyl Chloride ◽  
Fab Mass Spectrometry ◽  
Cross Coupling Reaction ◽  
Selective Substitution ◽  
Derivatives Of

The synthesis of nitrogen and boron substituted derivatives of the 1-amino-closo-dodecaborate anion(1-) 1 is reported. Reasonable yields of the [R2NH-B12H11]- derivatives (R = C6H5CH2, 2-C10H7CH2, n-C16H33, n-C12H25) were obtained via conventional alkylation of 1 in aqueous propan-2-ol, starting from bulky primary alkylhalides. These [R2NH-B12H11]- derivatives were subsequently methylated by dimethyl sulfate under similar conditions. Reaction of 1 with palmitoyl chloride gave under anhydrous conditions the corresponding N-acyl derivative. Reaction of 1 with hydroxymethyl-18-crown-6 tosylate in THF in the presence of NaH led to the novel [(18-crown-6-CH2)2NH-B12H11]- anion, the Cs+ salt of which exhibits unusual solubility properties. A direct cyclization reaction of pentaethylene glycol ditosylate with 1 gave under similar conditions [(15-azacrown)-5-B12H11]-, the first known closo-borate anion with an attached aza-crown ring. These species exhibit potentially interesting complexation efficiency and solubility properties. Selective substitution of the boron cage by a bulky naphthyl substituent was achieved by palladium-mediated cross-coupling reaction between 1 and 1-BrMgC10H7. All derivatives were characterized by high-field 11B, 1H NMR and negative FAB mass spectrometry methods.

scholarly journals Synthesis of 4-Alkyl-4H-1,2,4-triazole Derivatives by Suzuki Cross-coupling Reactions and Their Luminescence Properties

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 652 ◽  
Author(s):  
Monika Olesiejuk ◽  
Agnieszka Kudelko ◽  
Marcin Swiatkowski ◽  
Rafal Kruszynski
Keyword(s):  
Ionic Liquids ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Boronic Acids ◽  
Luminescence Properties ◽  
Coupling Reactions ◽  
Triazole Derivatives ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Derivatives Of

New derivatives of 4-alkyl-3,5-diaryl-4H-1,2,4-triazole were synthesized utilizing the Suzuki cross-coupling reaction. The presented methodology comprises of the preparation of bromine-containing 4-alkyl-4H-1,2,4-triazoles and their coupling with different commercially available boronic acids in the presence of ionic liquids or in conventional solvents. The obtained compounds were tested for their luminescence properties.

A Novel Reductive Cross-coupling Reaction of 2-nitrobenzoic Hydrazides and Aldehydes or Ketones Promoted by the Low-valence Titanium Reagent: An Access to 2,3,4,5-tetrahydro-1H-1,3,4-benzotriazepine-5-one Derivatives

2005 ◽  
Vol 2005 (9) ◽  
pp. 553-555 ◽  
Author(s):  
Daqing Shi ◽  
Chunling Shi ◽  
Liangce Rong ◽  
Juxian Wang ◽  
Qiya Zhuang ◽  
...  
Keyword(s):  
Elemental Analysis ◽  
Nmr Spectra ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Reductive Coupling ◽  
Facile Synthesis ◽  
H Nmr ◽  
Cross Coupling Reaction

A short and facile synthesis of a series of 2,3,4,5-tetrahydro-1H-1,3,4-benzotriazepine-5-one derivatives was accomplished in good yields via the intermolecular reductive coupling reaction of 2-nitrobenzoic hydrazides and aldehydes or ketones promoted by the low-valence titanium reagent (TiCl4/Zn system). Structures were established on the basis of elemental analysis, IR and 1H NMR spectra.

Palladium-Catalyzed Regioselective Heck–Suzuki–Miyaura Cascade Cyclization for the Synthesis of Trisubstituted Arylideneisoquinolinones

Synlett ◽  
2019 ◽  
Vol 30 (09) ◽  
pp. 1073-1076 ◽  
Author(s):  
M. Asgari ◽  
R. Mirzazadeh ◽  
B. Larijani ◽  
P. Rashidi Ranjbar ◽  
R. Rahimi ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Cascade Cyclization ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Derivatives Of

An Ugi four-component reaction was used to construct propargylamide starting materials for a subsequent domino Heck–Suzuki–Miyaura cross-coupling reaction to give derivatives of 4-benzylidene-1-oxo-3,4-dihydro-1H-isoquinoline.

scholarly journals Highly Luminescent 4H-1,2,4-Triazole Derivatives: Synthesis, Molecular Structure and Photophysical Properties

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5627
Author(s):  
Monika Olesiejuk ◽  
Agnieszka Kudelko ◽  
Marcin Świątkowski
Keyword(s):  
Photophysical Properties ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Luminescent Properties ◽  
Boronic Acids ◽  
Molecular Structures ◽  
X Ray ◽  
Cross Coupling Reaction ◽  
Alternative Approach ◽  
Large Quantum

An alternative approach to the Suzuki cross-coupling reaction is used to synthesize a series of new luminophores based on 4-alkyl-4H-1,2,4-triazole cores conjugated via 1,4-phenylene linker to fused-bicyclic and tricyclic aromatic, or heteroaromatic arrangements. The described methodology allows one to conduct the coupling reaction with the use of commercially available boronic acids in the presence of conventional solvents or ionic liquids and produced excellent yields. It was found that the use of ultrasounds or microwaves significantly accelerates the reaction. The obtained compounds exhibited high luminescent properties and a large quantum yield of emitted photons. The X-ray molecular structures of three highly conjugated 4H-1,2,4-triazole representatives are also presented.

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