scholarly journals Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane

2016 ◽  
Vol 12 ◽  
pp. 2614-2619 ◽  
Author(s):  
Riccardo Porta ◽  
Alessandra Puglisi ◽  
Giacomo Colombo ◽  
Sergio Rossi ◽  
Maurizio Benaglia
Keyword(s):  
Continuous Flow ◽  
Reaction Times ◽  
Nitro Compounds ◽  
Primary Amines ◽  
Flow Conditions ◽  
Metal Free ◽  
Nitro Derivatives ◽  
Aromatic Nitro ◽  
High Yields ◽  
First Time

The metal-free reduction of nitro compounds to amines mediated by trichlorosilane was successfully performed for the first time under continuous-flow conditions. Aromatic as well as aliphatic nitro derivatives were converted to the corresponding primary amines in high yields and very short reaction times with no need for purification. The methodology was also extended to the synthesis of two synthetically relevant intermediates (precursors of baclofen and boscalid).

Nitrile Oxide 1,3-Dipolar Cycloaddition by Dehydration of Nitromethane Derivatives Under Continuous Flow Conditions

2011 ◽  
Vol 64 (10) ◽  
pp. 1397 ◽  
Author(s):  
Malte Brasholz ◽  
Simon Saubern ◽  
G. Paul Savage
Keyword(s):  
Continuous Flow ◽  
Reaction Times ◽  
Nitro Compounds ◽  
Dipolar Cycloaddition ◽  
Flow Conditions ◽  
Nitrile Oxides ◽  
Aliphatic Nitrile ◽  
By Products ◽  
Flow Techniques

Aliphatic nitrile oxides were generated in situ, by dehydration of terminal nitro compounds, and reacted with dipolarophiles using continuous flow techniques to afford substituted isoxazolines. The yields of cycloadducts were comparable with traditional flask-based reactions but reaction times were much shorter. In-line scavenger cartridges conveniently removed by-products and unreacted reagents to give almost pure crude products. The process was demonstrated up to gram scale.

Synthesis of Imines and Amines from Furfurals Using Continuous Flow Processing

2017 ◽  
Vol 70 (10) ◽  
pp. 1069 ◽  
Author(s):  
Boris Bizet ◽  
Christian H. Hornung ◽  
Thomas M. Kohl ◽  
John Tsanaktsidis
Keyword(s):  
High Temperatures ◽  
Continuous Flow ◽  
Simple Procedure ◽  
Condensation Reaction ◽  
Reaction Times ◽  
Primary Amines ◽  
Reactive Site ◽  
Flow Conditions

A simple procedure for the condensation of the bio-derived furfurals, 5-(methyl)furfural (MF) and 5-(chloromethyl)furfural (CMF), with primary amines is described herein. The experiments were conducted in both batch and flow conditions, with reaction times as short as 60 s. Moderately high temperatures were demonstrated to be suitable for the condensation reaction of MF in a few minutes whereas milder conditions and longer reaction times were necessary for CMF. Under these conditions the amine did not react with the methyl-chlorine group, leaving a very reactive site after condensation.

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.

Metal-free hydroxylation of tertiary ketones under intensified and scalable continuous flow conditions

2020 ◽  
Vol 10 (1) ◽  
pp. 167-179 ◽  
Author(s):  
Victor-Emmanuel H. Kassin ◽  
Thomas Toupy ◽  
Guillaume Petit ◽  
Pauline Bianchi ◽  
Elena Salvadeo ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Flow Conditions ◽  
Metal Free

scholarly journals Synthesis of Bis-2,3-dihydroquinazolin-4(1H)-ones and 2,3-Dihydroquinazolin-4(1H)-ones Derivatives with the Aid of Silica-Supported Preyssler Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Ali Gharib ◽  
Bibi Robabeh Hashemipour Khorasani ◽  
Manouchehr Jahangir ◽  
Mina Roshani ◽  
Reza Safaee
Keyword(s):  
Primary Amine ◽  
Ammonium Carbonate ◽  
Aromatic Aldehydes ◽  
Product Yield ◽  
Primary Amines ◽  
Isatoic Anhydride ◽  
One Pot ◽  
High Yields ◽  
First Time

One-pot three-component condensation of isatoic anhydride with primary amines or ammonium carbonate and aromatic aldehydes in refluxing ethanol in the presence of catalytic amounts of silica-supported preyssler nanoparticles (SPNP) afforded the corresponding 2,3-dihydroquinazolin-4(1H)-ones in high yields, and bis-dihydroquinazolinones were synthesized for the first time by a novel pseudo-five-component condensation of isatoic anhydride, a primary amine, and a dialdehyde in water. The catalyst is reusable and can be applied several times without any decrease in product yield.

Metal-Free Addition of Boronic Acids to Silylnitronates

Synlett ◽  
2020 ◽  
Vol 31 (09) ◽  
pp. 856-860
Author(s):  
Laurent El Kaïm ◽  
Mansour Dolé Kerim ◽  
Pakoupati Boyode ◽  
Julian Garrec
Keyword(s):  
Reaction Mechanism ◽  
Double Bond ◽  
Boronic Acids ◽  
Dft Study ◽  
Metal Free ◽  
Nitro Derivatives ◽  
Oxime Derivatives ◽  
Nitrogen Double Bond ◽  
First Time ◽  
Aryl Transfer

We report for the first time a metal-free addition of boronic acids to silylnitronates to afford oxime derivatives through aryl transfer on the carbon nitrogen double bond. A reaction mechanism has been proposed in relation with a DFT study on the key aryl transfer. This arylation process is effective for cycloalkenyl nitro derivatives leading to oximes that may be oxidatively converted into 3-arylisoxazole derivatives.

ChemInform Abstract: Metal-Free Reduction of Aromatic Nitro Compounds to Aromatic Amines with B2pin2in Isopropanol.

ChemInform ◽  
2016 ◽  
Vol 47 (42) ◽  
Author(s):  
Hongtao Lu ◽  
Zhiyue Geng ◽  
Jingya Li ◽  
Dapeng Zou ◽  
Yusheng Wu ◽  
...  
Keyword(s):  
Aromatic Amines ◽  
Nitro Compounds ◽  
Metal Free ◽  
Aromatic Nitro Compounds ◽  
Aromatic Nitro

scholarly journals Dimeric cyclobutane formation under continuous flow conditions using organophotoredox catalysed [2+2]-cycloaddition

2021 ◽  
Author(s):  
Helena Grantham ◽  
Marc Kimber
Keyword(s):  
Natural Products ◽  
Continuous Flow ◽  
Reaction Times ◽  
Functional Materials ◽  
Synthetic Route ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
New Class ◽  
Cyclobutane Dimers ◽  
Flow Study

Radical cation-initiated dimerization of electron rich alkenes is an expedient method for the synthesis of cyclobutanes. By merging organophotoredox catalysis and continuous flow technology a batch versus continuous flow study has been performed providing a convenient synthetic route to an important carbazole cyclobutane material dimer t-DCzCB using less only 0.1 mol% of an organophotoredox catalyst. The scope of this methodology was explored giving a new class of functional materials, as well as an improved synthetic route to styrene based lignan dimeric natural products. The cyclobutane dimers could be isolated in higher chemical yields under continuous flow conditions and reaction times were reduced significantly compared to traditional batch reaction conditions.

scholarly journals Recent Advances in Continuous-Flow Reactions Using Metal-Free Homogeneous Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1321
Author(s):  
Naoto Sugisawa ◽  
Hiroyuki Nakamura ◽  
Shinichiro Fuse
Keyword(s):  
Continuous Flow ◽  
Low Cost ◽  
Reaction Times ◽  
Toxic Metal ◽  
Homogeneous Catalysts ◽  
Precise Control ◽  
Metal Free ◽  
Acidic Catalysts ◽  
Ready Availability ◽  
Low Toxicity

Developments that result in high-yielding, low-cost, safe, scalable, and less-wasteful processes are the most important goals in synthetic organic chemistry. Continuous-flow reactions have garnered much attention due to many advantages over conventional batch reactions that include precise control of short reaction times and temperatures, low risk in handling dangerous compounds, and ease in scaling up synthesis. Combinations of continuous-flow reactions with homogeneous, metal-free catalysts further enhances advantages that include low-cost and ready availability, low toxicity, higher stability in air and water, and increased synthetic efficiency due to the avoidance of the time-consuming removal of toxic metal traces. This review summarizes recently reported continuous-flow reactions using metal-free homogeneous catalysts and classifies them either as acidic catalysts, basic catalysts, or miscellaneous catalysts. In addition, we compare the results between continuous-flow conditions and conventional batch conditions to reveal the advantages of using flow reactions with metal-free homogeneous catalysts.

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