Search results for "coupling reaction"

An insight into the synthesis of novel aryl-substituted alicyclic β-amino acid derivatives through substrate-directed palladium-catalysed regio- and …

2015

Novel aryl-substituted alicyclic β-amino acid derivatives were synthesized through substrate-determined palladium-catalysed cross-coupling of aryl iodides with five- or six-membered cycloalkene β-amino esters. The arylations were investigated with different catalysts, solvents, bases and aryl halides, and with some cyclohexene 2-aminocarboxylate isomers. The stereochemistry and the position of the ring olefinic bond of the starting 2-aminocycloalkanecarboxylate influenced the coupling reaction, and predetermined the structure of the arylated product.

Post-synthetic methods for functionalization of imidazole-fused porphyrins

2018

Several methods for the post-synthetic modification of imidazo[4,5-[Formula: see text]]porphyrins are reported. First, a synthetic approach to the isomeric difunctionalized porphyrins, containing two [Formula: see text]-fused 2-aryl-1[Formula: see text]-imidazole cycles at adjacent or opposite pyrrole rings of the macrocycle is developed. The core chemistry of this synthetic route is the transformation of 2-aryl-1[Formula: see text]-imidazo[4,5-[Formula: see text]]porphyrins into corresponding imidazodioxochlorins followed by Debus–Radziszewski condensation with aromatic aldehyde. Next, 2-(4-bromophenyl)-1[Formula: see text]-imidazo[4,5-[Formula: see text]]-5,10,15,20-tetramesitylporphyrin…

Erweiterte Konjugation in unsymmetrischen Stilbenylsquarainen

1998

Extended Conjugation in Stilbenylsquaraines Unsymmetrical 1-aryl-3-stilbenylsquaraines 2a–e and 1,3-bis(stilbenyl)squaraines 3a–c were prepared by CC coupling reactions of the corresponding substituted arenes with derivatives of squaric acid (Schemes 2 and 3). Dialkylamino and alkoxy groups enhance the solubility of these dyes and enlarge the intramolecular charge transfer of these donor–acceptor–donor systems. The extended conjugation of the stilbene units – in comparison with arene building blocks – leads to significant bathochromic shifts in the Vis/NIR absorption spectra.

ChemInform Abstract: Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.

2016

A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature.

ChemInform Abstract: Preparation and Nonlinear Optics of Monodisperse Oligo(1,4-phenyleneethynylene)s.

2010

Oligo(1,4-phenyleneethynylene)s 1a−e, with solubilizing propoxy side chains, were prepared by use of Hagihara−Sonogashira coupling reactions. The synthetic strategy was based on a building block system and on the use of trimethylsilyl and triisopropylsilyl protecting groups that could be cleaved selectively. The extension of the conjugation with an increasing number of repeat units provokes a bathochromic shift of the long wavelength absorption and a superlinear increase of the second hyperpolarizability |γ|. The corresponding third harmonic generation (THG) measurements were performed using polystyrene matrices and variable laser wavelengths. We conclude that the conjugation length is much…

Optimization Strategies for the Anodic Phenol‐Arene Cross‐Coupling Reaction

2021

Polycondensed nitrogen heterocycles. Part 22. Pyrrolo[3,4-d]-1,2,3-triazines: A new ring system as potential antineoplastic agent

1989

Diazotization of the 3-aminopyrrole-4-carboxamides 6a,b under different conditions directly led to the new ring system pyrrolo[3,4-d]-1,2,3-triazine in excellent yields through an intramolecular coupling reaction. In all the cases it was impossible to isolate the intermediate 3-diazopyrroles.

Anodic Formation of Aryl Mesylates through Dehydrogenative Coupling Reaction

2018

Versatile oxidative approach to carbazoles and related compounds using MoCl5.

2013

The unique oxidizing power of molybdenum pentachloride provides an easy to perform, versatile, and high yielding method to construct carbazoles and the corresponding dibenzo analogues of thiophene, furan, and selenophene. The coupling reaction tolerates a variety of functional groups. The synthesis is highly modular. By this approach a precursor for the naturally occurring carbazole koenigicine was prepared.

Synthese von methyl- und methylenosubstituierten p-Oligophenylenen durch cokondensierende ULLMANN-Reaktion. 12. Mitt.

1963

Es wird ein Syntheseverfahren fur p-Oligophenylene beschrieben, das eine Variante der ULLMANNschen Biarylverknupfungsreaktion darstellt. Dabei wird eine bifunktionelle Jodverbindung mit einem groseren Uberschus an einer monofunktionellen Komponente umgesetzt. Dieses als cokondensierende ULLMANN-Reaktion bezeichnete Syntheseprinzip, das Ausbeuten von 40–50% d. Th. ergibt, wird eingehend erlautert und die Leistungsfahigkeit an zahlreichen Beispielen belegt. Neben einer Reihe von methylsubstituierten p-Oligophenylenen, welche Derivate vom p-Terphenyl bis zum p-Septiphenyl einschliest, werden auch Oligophenylene mit endstandigem oder mittelstandigem Fluorenrest als Strukturelement hergestellt. …