scholarly journals The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors

2016 ◽  
Vol 12 ◽  
pp. 1987-2004 ◽  
Author(s):  
Faith M Akwi ◽  
Paul Watts
Keyword(s):  
Continuous Flow ◽  
Coupling Reaction ◽  
Azo Compounds ◽  
Coupling Reactions ◽  
Azo Coupling ◽  
Reaction Conditions ◽  
Flow Rates ◽  
Flow Synthesis ◽  
Optimum Flow

In this paper, a micro-fluidic optimized process for the continuous flow synthesis of azo compounds is presented. The continuous flow synthesis of Sudan II azo dye was used as a model reaction for the study. At found optimal azo coupling reaction temperature and pH an investigation of the optimum flow rates of the reactants for the diazotization and azo coupling reactions in Little Things Factory-MS microreactors was performed. A conversion of 98% was achieved in approximately 2.4 minutes and a small library of azo compounds was thus generated under these reaction conditions from couplers with aminated or hydroxylated aromatic systems. The scaled up synthesis of these compounds in PTFE tubing (i.d. 1.5 mm) was also investigated, where good reaction conversions ranging between 66–91% were attained.

Reactions of 4-Amino-3-penten-2-one and Its NSubstituted Derivatives with Diazonium Ions

1995 ◽  
Vol 60 (8) ◽  
pp. 1367-1379 ◽  
Author(s):  
Vladimír Macháček ◽  
Alexandr Čegan ◽  
Aleš Halama ◽  
Olga Rožňavská ◽  
Vojeslav Štěrba
Keyword(s):  
Coupling Reaction ◽  
Butyl Alcohol ◽  
Azo Compounds ◽  
Coupling Reactions ◽  
Azo Coupling ◽  
Alcohol Water ◽  
Diazonium Ions ◽  
Coupling Rate ◽  
Reaction Orders ◽  
Intramolecular Hydrogen

Azo coupling reactions of benzenediazonium salts with substituted 4-amino-3-penten-2-ones take place at the C-3 atom. 1H and 13C NMR spectroscopy has been used to study the structure of both the starting enaminones and coupling products. In CDCl3, 3-(4-chlorophenylhydrazono)-2-(4-methylphenylimino)-4-pentanone exists in hydrazo form whereas 4-amino-3-(4-chlorophenylazo)-3-penten-2-one is present as a mixture of two azo compounds differing probably in the arrangement of the intramolecular hydrogen bond. The azo coupling reaction kinetics have been studied in acetate buffers and methanol-water or tert-butyl alcohol-water mixtures. The coupling rate has been found independent of pH and buffer concentration. The reaction orders with respect to the starting compounds have been determined and the reaction mechanism is suggested. Linear dependence has been found between log kobs and substituent constants according to the Hammett or Yukawa-Tsuno equations.

An Unprecedented Cyano-Induced Sodium Nitrite-Catalyzed C(sp3)-H and C(sp2)-H Coupling Reaction

2018 ◽  
Vol 15 (7) ◽  
pp. 989-994 ◽  
Author(s):  
Ling Li ◽  
Bo Su ◽  
Yuxiu Liu ◽  
Qingmin Wang
Keyword(s):  
Sodium Nitrite ◽  
Oxidative Coupling ◽  
High Resolution Mass Spectrometry ◽  
Coupling Reaction ◽  
13C Nmr Spectroscopy ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
1H And 13C Nmr ◽  
Oxidative Coupling Reaction ◽  
Oxidative Coupling Reactions

Aim and Objective: During the investigation of sodium nitrite-catalyzed oxidative coupling reaction of aryls, an unprecedented C(sp2)-H and C(sp3)-H coupling of substituted 2-aryl acetonitrile was found. Materials and Methods: The structure of the coupled product was confirmed by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry (HRMS), and comparison of its derivatives with known compounds. The effects of methoxy group in the benzene ring on the reaction were evaluated. Results: The optimized reaction conditions are summarized as follows: CF3SO3H/substrate = 1.5 equiv., NaNO2/substrate = 0.3 equiv., CH3CN as solvent. 2-(4-Methoxyphenyl)acetonitrile and 2-(3,4,5- trimethoxyphenyl)acetonitrile could also generate C(sp2)-H and C(sp3)-H coupling. The coupling reaction occurred as a typical radial mechanism. Conclusion: An unprecedented cyano-induced, NaNO2-catalyzed oxidative C(sp3)-H and C(sp2)-H coupling was reported. The reaction proceeded under very mild conditions, using O2 in the air as terminal oxidant. The unique oxidative manner might provide more inspiration for the development of intriguing oxidative coupling reactions.

scholarly journals Nanofiltration-Enabled In Situ Solvent and Reagent Recycle for Sustainable Continuous-Flow Synthesis

ChemSusChem ◽  
2017 ◽  
Vol 10 (17) ◽  
pp. 3435-3444 ◽  
Author(s):  
Tamas Fodi ◽  
Christos Didaskalou ◽  
Jozsef Kupai ◽  
Gyorgy T. Balogh ◽  
Peter Huszthy ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Flow Synthesis

scholarly journals The Eschenmoser coupling reaction under continuous-flow conditions

2011 ◽  
Vol 7 ◽  
pp. 1164-1172 ◽  
Author(s):  
Sukhdeep Singh ◽  
J Michael Köhler ◽  
Andreas Schober ◽  
G Alexander Groß
Keyword(s):  
Continuous Flow ◽  
Elevated Temperatures ◽  
Reaction Times ◽  
Coupling Reaction ◽  
Flow Chemistry ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Reaction Proceeds

The Eschenmoser coupling is a useful carbon–carbon bond forming reaction which has been used in various different synthesis strategies. The reaction proceeds smoothly if S-alkylated ternary thioamides or thiolactames are used. In the case of S-alkylated secondary thioamides or thiolactames, the Eschenmoser coupling needs prolonged reaction times and elevated temperatures to deliver valuable yields. We have used a flow chemistry system to promote the Eschenmoser coupling under enhanced reaction conditions in order to convert the demanding precursors such as S-alkylated secondary thioamides and thiolactames in an efficient way. Under pressurized reaction conditions at about 220 °C, the desired Eschenmoser coupling products were obtained within 70 s residence time. The reaction kinetics was investigated and 15 examples of different building block combinations are given.

scholarly journals Efficient in situ N-heterocyclic carbene palladium(ii) generated from Pd(OAc)2 catalysts for carbonylative Suzuki coupling reactions of arylboronic acids with 2-bromopyridine under inert conditions leading to unsymmetrical arylpyridine ketones: synthesis, characterization and cytotoxic activities

RSC Advances ◽  
2018 ◽  
Vol 8 (70) ◽  
pp. 40000-40015 ◽  
Author(s):  
Nedra Touj ◽  
Abdullah S. Al-Ayed ◽  
Mathieu Sauthier ◽  
Lamjed Mansour ◽  
Abdel Halim Harrath ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Suzuki Coupling ◽  
Boronic Acids ◽  
Cytotoxic Activities ◽  
Coupling Reactions ◽  
Component System ◽  
Arylboronic Acids ◽  
Cross Coupling Reaction

The in situ prepared four component system Pd(OAc)2, 1,3-dialkylbenzimidazolium halides 2a–i and 4a–i, K2CO3 under CO atmosphere catalyses carbonylative cross-coupling reaction of 2-bromopyridine with various boronic acids to yield unsymmetrical arylpyridine ketones.

An easily prepared palladium-hydrogel nanocomposite catalyst for C–C coupling reactions

2014 ◽  
Vol 2 (44) ◽  
pp. 18952-18958 ◽  
Author(s):  
Mitasree Maity ◽  
Uday Maitra
Keyword(s):  
Palladium Nanoparticles ◽  
Room Temperature ◽  
Coupling Reaction ◽  
Coupling Reactions ◽  
Sodium Cyanoborohydride ◽  
Efficient Catalyst ◽  
Suzuki Coupling Reaction ◽  
Reaction In Water ◽  
Hydrogel Nanocomposite

Palladium nanoparticles were efficiently prepared in situ by sodium cyanoborohydride reduction of Pd(ii) at room temperature using calcium-cholate hydrogel fibers as templates. The PdNPs self-organize on the gel fibers, which supports the controlled growth as well as stabilization of PdNPs. The hybrid xerogel was used as an efficient catalyst for the Suzuki coupling reaction in water.

Ligand free copper(i)-catalyzed synthesis of diaryl ether with Cs2CO3via a free radical path

2015 ◽  
Vol 44 (27) ◽  
pp. 12086-12090 ◽  
Author(s):  
Hong-Jie Chen ◽  
Mei-Chun Tseng ◽  
I-Jui Hsu ◽  
Wei-Ting Chen ◽  
Chien-Chung Han ◽  
...  
Keyword(s):  
Free Radical ◽  
Catalytic Reaction ◽  
Coupling Reaction ◽  
Reaction Conditions ◽  
Esi Ms ◽  
Ms Analysis ◽  
Diaryl Ether ◽  
Ligand Free

Complexes [Cu(i)(2,4-dimethylphenoxy)2]− (A) and [Cu(ii)(2,4-dimethylphenoxy)2(p-tolyl)]− (B) were observed by in situ ESI-MS analysis of the ligand free copper(i)-catalyzed C–O coupling reaction using Cs2CO3 under the catalytic reaction conditions.

scholarly journals Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

2018 ◽  
Vol 14 ◽  
pp. 1871-1884 ◽  
Author(s):  
Siva Sankar Murthy Bandaru ◽  
Darinka Dzubiel ◽  
Heiko Ihmels ◽  
Mohebodin Karbasiyoun ◽  
Mohamed M A Mahmoud ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Binding Constants ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Sonogashira Coupling ◽  
Reaction Conditions ◽  
Quadruplex Dna ◽  
Cross Coupling Reactions ◽  
Sonogashira Coupling Reaction

9-Arylbenzo[b]quinolizinium derivatives were prepared with base-free Suzuki–Miyaura coupling reactions between benzo[b]quinolizinium-9-trifluoroborate and selected benzenediazonium salts. In addition, the Sonogashira coupling reaction between 9-iodobenzo[b]quinolizinium and the arylalkyne derivatives yielded four novel 9-(arylethynyl)benzo[b]quinolizinium derivatives under relatively mild reaction conditions. The 9-(N,N-dimethylaminophenylethynyl)benzo[b]quinolizinium is only very weakly emitting, but the emission intensity increases by a factor >200 upon protonation, so that this derivative may operate as pH-sensitive light-up probe. Photometric and fluorimetric titrations of duplex and quadruplex DNA to 9-(arylethynyl)benzo[b]quinolizinium derivatives revealed a significant binding affinity of these compounds towards both DNA forms with binding constants ofKb= 0.2–2.2 × 105M−1.

Regiospecific Palladium-Catalyzed Cross-Coupling Reactions Using the Operational Equivalent of 1,3-Dilithiopropyne

Synthesis ◽  
2020 ◽  
Vol 52 (16) ◽  
pp. 2387-2394 ◽  
Author(s):  
Jorge A. Cabezas ◽  
Natasha Ferllini
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Terminal Alkyne ◽  
Copper Iodide ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
High Yields

A regiospecific palladium-catalyzed cross-coupling reaction using the operational equivalent of the dianion 1,3-dilithiopropyne, with aromatic iodides is reported. This reaction gives high yields of 1-propyn-1-yl-benzenes and 2-(propyn-1-yl)thiophenes in the presence of catalytic amounts of palladium(0) or (II) and stoichiometric amounts of copper iodide. No terminal alkyne or allene isomers were detected. Reaction conditions were very mild and several functional groups were tolerated.

scholarly journals Thiol–ene coupling reaction achievement and monitoring by “in situ” UV irradiation NMR spectroscopy

RSC Advances ◽  
2020 ◽  
Vol 10 (42) ◽  
pp. 25214-25222
Author(s):  
Natalia Toncheva-Moncheva ◽  
Miroslav Dangalov ◽  
Nikolay G. Vassilev ◽  
Christo P. Novakov
Keyword(s):  
Nmr Spectroscopy ◽  
Uv Irradiation ◽  
Glycidyl Ether ◽  
Coupling Reaction ◽  
Polyethylene Glycols ◽  
Coupling Reactions ◽  
Uv Illumination ◽  
Allyl Glycidyl Ether

An “In situ” LED UV illumination NMR setup for achievement of initiator-free coupling reactions of allyl-functionalized poly(allyl glycidyl ether) with polyethylene glycols thiols.

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