scholarly journals Catalytic Synthesis of Pyrano- and Furoquinolines Using Nano Silica Chromic Acid at Room Temperature

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ali Gharib ◽  
Manouchehr Jahangir
Keyword(s):  
Room Temperature ◽  
Chromic Acid ◽  
Heterogeneous Reaction ◽  
Similar Reaction ◽  
Coupling Reactions ◽  
Nano Silica ◽  
Reaction Conditions ◽  
Enol Ethers ◽  
High Yields ◽  
Heterogeneous Reaction Conditions

Nano silica chromic acid (nano-SCA) is found to catalyze efficiently the three component-coupling reactions of aldehydes, amines, and cyclic enol ethers such as 3,4-dihydro-2H-pyran and 2,3-dihydrofuran under mild conditions to afford the corresponding pyrano- and furanoquinolines in excellent yields with high endoselectivity. Interestingly, 2,3-dihydrofuran afforded selectively endoproducts under the similar reaction conditions. Heterogeneous reaction conditions, easy procedure, short reaction time, and high yields are some important advantages of this method.

Effects of salts on the kinetics of oxidation of alkenes by thallic salts in aqueous solutions

1981 ◽  
Vol 46 (3) ◽  
pp. 693-700 ◽  
Author(s):  
Milan Strašák ◽  
Jaroslav Majer
Keyword(s):  
Aqueous Solutions ◽  
Phase Transfer ◽  
Heterogeneous Reaction ◽  
Qualitative Model ◽  
Kinetic Effect ◽  
Tetraalkylammonium Salts ◽  
Reaction Conditions ◽  
Kinetics Of Oxidation ◽  
Kinetics Of ◽  
Heterogeneous Reaction Conditions

The kinetics of oxidation of alkenes by thallic sulphate in aqueous solutions, involving the two reaction steps-the hydroxythallation and the dethallation - was studied, and the effect of salts on the kinetics was examined; this made it possible to specify more precisely the reaction mechanism and to suggest a qualitative model of the reaction coordinate. It was found that in homogeneous as well as in heterogeneous reaction conditions, the reaction can be accelerated appreciably by adding tetraalkylammonium salts. These salts not only operate as catalysts of the phase transfer, but also exert a significant kinetic effect, which can be explained with a simplification in terms of a stabilization of the transition state of the reaction.

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.

A Copper(I)-Mediated Tandem Three-Component Synthesis of 5-Allyl-1,2,3-triazoles

Synthesis ◽  
2019 ◽  
Vol 52 (05) ◽  
pp. 744-754
Author(s):  
Yoona Song ◽  
Soyun Lee ◽  
Palash Dutta ◽  
Jae-Sang Ryu
Keyword(s):  
Room Temperature ◽  
Reaction Conditions ◽  
One Pot ◽  
Three Component Reaction ◽  
High Yields

A copper(I)-mediated tandem three-component reaction using alkynes, azides, allyl iodides, CuI and NaNH2 is developed. The reactions proceed smoothly at room temperature to afford 5-allyl-1,2,3-triazoles, which can be further converted into 1,2,3-triazole-fused tricyclic scaffolds. This method features an efficient one-pot cascade route using commercial alkynes and affords the corresponding 5-allyl-1,2,3-triazoles with high yields and good selectivity under mild reaction conditions.

scholarly journals Efficient synthesis of pyrazolopyridines containing a chromane backbone through domino reaction

2019 ◽  
Vol 15 ◽  
pp. 874-880
Author(s):  
Razieh Navari ◽  
Saeed Balalaie ◽  
Saber Mehrparvar ◽  
Fatemeh Darvish ◽  
Frank Rominger ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Selectivity ◽  
Domino Reaction ◽  
Primary Amines ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Reaction Conditions ◽  
Efficient Approach ◽  
Three Component Reaction ◽  
High Yields

An efficient approach for the synthesis of pyrazolopyridines containing the aminochromane motif through a base-catalyzed cyclization reaction is reported. The synthesis was carried out through a three-component reaction of (arylhydrazono)methyl-4H-chromen-4-one, malononitrile, primary amines in the presence of Et3N at room temperature. However, carrying out the reaction under the same conditions without base led to a fused chromanyl-cyanopyridine. High selectivity, high atom economy, and good to high yields in addition to mild reaction conditions are the advantages of this approach.

scholarly journals Rapid Access to Diverse Potassium Acyltrifluoroborates (KATs) Through Late-Stage Chemoselective Cross-Coupling Reactions

2020 ◽  
Author(s):  
Xingwang Deng ◽  
Guan Zhou ◽  
Xiao Han ◽  
Khadim Ullah ◽  
Rajavel Srinivasan
Keyword(s):  
Late Stage ◽  
Materials Science ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Library Synthesis ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Rapid Diversification ◽  
High Yields ◽  
Opening Up

Potassium acyltrifluoroborates (KATs) are opening up new avenues in chemical biology, materials science and synthetic organic chemistry due to their intriguing reactivities. However, the synthesis of these compounds remains mostly complicated and time-consuming. This lack of a rapid and facile synthetic route has hindered the widespread adoption of KAT-based chemistry, especially in the areas of compound library synthesis and drug discovery. Herein, we have developed chemoselective Pd-catalyzed approaches for the late-stage diversification of arenes bearing pre-functionalized KATs. These approaches feature chemoselective cross-coupling, rapid diversification, functional group tolerance, mild reaction conditions, and high yields.

scholarly journals Carbonyl Sulfide-Mediated Synthesis of Peptides with Amino Acid Ionic Liquids

2019 ◽  
Author(s):  
Ming Chen ◽  
Xihan Yu
Keyword(s):  
Ionic Liquids ◽  
Amino Acid ◽  
Room Temperature ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Carbonyl Sulfide ◽  
Coupling Reactions ◽  
Volcanic Emission ◽  
High Yields ◽  
Primordial Earth

Carbonyl sulfide (OCS), the component of volcanic emission, has been found to induce the condensation of amino acids under simulated primordial earth conditions. However, the applications of OCS in peptide chemical synthesis is still limited by their heterogeneities and low efficiencies. We herein report an OCS-mediated approach for solid-phase peptide synthesis using amino acid ionic liquids as recyclable reactants. The coupling reactions required no base and solvent and was completed in minutes at room temperature. The applicability and sustainability of this approach were demonstrated by the facile syntheses of peptides with remarkably high yields.

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