Heterogeneous Copper(I)-Catalyzed Cascade Addition–Oxidative Cyclization of Nitriles with 2-Aminopyridines or Amidines: Efficient and Practical Synthesis of 1,2,4-Triazoles

Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 2014-2022 ◽  
Author(s):  
Jianhui Xia ◽  
Xue Huang ◽  
Mingzhong Cai
Keyword(s):  
Catalytic Activity ◽  
Oxidative Cyclization ◽  
Triazole Derivatives ◽  
Step Procedure ◽  
Practical Synthesis ◽  
High Yields ◽  
Mcm 41

The heterogeneous cascade addition-oxidative cyclization of nitriles with 2-aminopyridines or amidines was achieved in 1,2-dichlorobenzene or DMSO at 120–130 °C by using a 1,10-phenanthroline-functionalized MCM-41-supported copper(I) complex [Phen-MCM-41-CuBr] as the catalyst and air as the oxidant. The approach was used to generate a wide variety of 1,2,4-triazole derivatives in mostly high yields. This heterogeneous copper(I) catalyst could be easily prepared in a two-step procedure from commercially or readily available and inexpensive reagents and it exhibited higher catalytic activity than the CuBr/1,10-Phen system. Phen-MCM-41-CuBr was also easy to recover and was recyclable up to eight times with almost consistent activity.

Recyclable Heterogeneous Copper(II)-Catalyzed Oxidative Cyclization of 2-Pyridine Ketone Hydrazones Towards [1,2,3]Triazolo[1,5-a]pyridines

Synthesis ◽  
2019 ◽  
Vol 51 (23) ◽  
pp. 4487-4497
Author(s):  
Gan Jiang ◽  
Yang Lin ◽  
Mingzhong Cai ◽  
Hong Zhao
Keyword(s):  
Catalytic Activity ◽  
Present Method ◽  
Room Temperature ◽  
Simple Procedure ◽  
Significant Loss ◽  
Oxidative Cyclization ◽  
Hydrazine Monohydrate ◽  
One Pot ◽  
High Yields ◽  
Mcm 41

The heterogeneous copper(II)-catalyzed oxidative cyclization of 2-pyridine ketone hydrazones was achieved in ethyl acetate at room temperature in the presence of an MCM-41-anchored bidentate 2-aminoethylamino copper(II) catalyst [MCM-41-2N-Cu(OAc)2], in the presence of air as the oxidant, yielding a wide variety of [1,2,3]triazolo[1,5-a]pyridines in mostly good to high yields. The present method was also applied to the direct one-pot synthesis of [1,2,3]triazolo[1,5-a]pyridines from 2-acylpyridine derivatives and hydrazine monohydrate. Importantly, this supported copper(II) catalyst could be conveniently obtained via a simple procedure from easily available and inexpensive reagents, recovered by filtration of the reaction mixture, and reused at least seven times without a significant loss of catalytic activity.

A Highly Efficient Heterogeneous Copper-Catalyzed Oxidative Cyclization of Benzylamines and 1,3-Dicarbonyl Compounds To Give Trisubstituted Oxazoles

Synthesis ◽  
2019 ◽  
Vol 51 (16) ◽  
pp. 3091-3100
Author(s):  
Li Wei ◽  
Shengyong You ◽  
Yuxin Tuo ◽  
Mingzhong Cai
Keyword(s):  
Copper Catalyst ◽  
Oxidative Cyclization ◽  
Dicarbonyl Compounds ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Intermolecular Cyclization ◽  
Step Procedure ◽  
Mcm 41

The heterogeneous copper-catalyzed cascade oxidative cyclization between benzylamines and 1,3-dicarbonyl compounds was achieved by using the 3-(2-aminoethylamino)propyl-functionalized MCM-41-immobilized copper(II) complex [MCM-41-2N-Cu(OAc)2] as catalyst and t-BuOOH (TBHP) as oxidant, with iodine as additive, under mild conditions, yielding a wide variety of 2,4,5-trisubstituted oxazoles in mostly good to excellent yields. This heterogeneous copper catalyst can be facilely prepared via a simple two-step procedure from readily available and inexpensive reagents and exhibits a slightly higher activity than Cu(OAc)2. MCM-41-2N-Cu(OAc)2 is also easy to recover and can be recycled up to eight times with almost consistent activity. The reaction is the first example of heterogeneous copper-catalyzed intermolecular cyclization for the construction of polysubstituted oxazoles.

The Immobilized Copper on Nickel Ferrite: A Magnetically Superior Nanocatalyst for Chemoselective and Knoevenagel Synthesis of Bisdimedones and 1,8-Dioxo-octahydroxanthenes under Solvent-Free Conditions

2019 ◽  
Vol 16 (6) ◽  
pp. 939-947 ◽  
Author(s):  
Behzad Zeynizadeh ◽  
Soleiman Rahmani ◽  
Arezu Hallaj
Keyword(s):  
Catalytic Activity ◽  
Aromatic Aldehydes ◽  
Catalyst System ◽  
Solvent Free ◽  
Biologically Active ◽  
Knoevenagel Reaction ◽  
Reaction Conditions ◽  
Step Procedure ◽  
Solvent Free Conditions ◽  
High Yields

Aim and Objective: Nowadays, bisdimedones and 1,8-dioxo-octahydroxanthenes are considered as biologically active materials. Due to this, the synthesis of the mentioned materials is the subject of more interest. Although most of the reported methods have their own merits, however, they generally require the use of expensive reagents, hazardous organic solvents, a tedious workup procedure and reduced recyclability of the applied catalyst system. Overcoming of the above mentioned drawbacks, therefore, encouraged us to investigate the capability of nanostructured NiFe2O4@Cu towards the synthesis of bisdimedones and 1,8- dioxo-octahydroxanthenes under green reaction conditions. Materials and Methods: Nanoparticles of NiFe2O4@Cu were prepared via a two-step procedure including the preparation of NiFe2O4 by solid-state grinding of Ni(OAc)2·4H2O and Fe(NO3)3·9H2O in the presence of NaOH followed by the immobilization of Cu(0) on the surface of NiFe2O4 nucleus via hydrazine hydrate reduction of Cu(NO3)2·3H2O. Results: After the synthesis of NiFe2O4@Cu, the catalytic activity of the Cu-nanocatalyst towards Knoevenagel reaction of aromatic aldehydes with dimedone under different reaction conditions was investigated. The examinations showed that using the molar equivalents of aromatic aldehydes (1 mmol) and dimedone (2 mmol) in the presence of 0.15 g NiFe2O4@Cu under solvent-free conditions chemoselectively afforded structurally different bisdimedone products at 60°C and 1,8-dioxo-octahydroxanthenes at 120°C. Conclusion: In this study, magnetically, nanoparticles of NiFe2O4@Cu were prepared and then characterized using different analyses. The catalytic activity of the prepared Cu-nanocatalyst was also studied towards solvent-free Knoevenagel condensation of aromatic aldehydes with dimedone. All the reactions were carried out within 15-240 min to afford bisdimedone and 1,8-dioxo-octahydroxanthene products in high yields.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Temperature Dependent Green Synthesis of 3-Carboxycoumarins and 3,4-unsubstituted Coumarins

2019 ◽  
Vol 16 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Jack van Schijndel ◽  
Dennis Molendijk ◽  
Luiz Alberto Canalle ◽  
Erik Theodorus Rump ◽  
Jan Meuldijk
Keyword(s):  
Knoevenagel Condensation ◽  
Ammonium Bicarbonate ◽  
Solvent Free ◽  
Temperature Dependent ◽  
Step Procedure ◽  
Synthetic Routes ◽  
High Yields ◽  
Temperature Optima ◽  
Solvent Free Synthesis ◽  
Full Conversion

Aim and Objective: Because of the low abundance of 3,4-unsubstituted coumarins in plants combined with the complex purification process required, synthetic routes towards 3,4-unsubstituted coumarins are especially valuable. In the present work, we explore the possibilities of a solvent-free Green Knoevenagel condensation on various 2-hydroxybenzaldehyde derivatives and malonic acid without the use of toxic organocatalysts like pyridine and piperidine but only use ammonium bicarbonate as the catalyst. Materials and Methods: To investigate the scope of the Green Knoevenagel condensation for the synthesis of 3,4-unsubstituted coumarins, various 2-hydroxybenzaldehyde derivatives were screened as starting material in the optimized two-step procedure developed for 2-hydroxybenzaldehyde. </P><P> Results: This study shows that the intramolecular esterification and the decarboxylation are in competition, but show different temperature optima. In order to suppress premature decarboxylation and maximize the yield of coumarin, a two-step procedure was adopted. The reaction mixture containing ammonium bicarbonate is initially kept at 90ºC for 1 hour. After completion of the cyclization, the temperature of the reaction mixture is increased to 140ºC for 2 hours. Following this protocol, coumarin could be isolated with a yield of 95%. Conclusion: A two-step procedure for the solvent-free synthesis of several 3,4-unsubstituted coumarins was developed using ammonium bicarbonate, resulting in high yields of the desired products. Moreover, this procedure has a low E-factor and is, therefore an environmental friendly reaction in line with the principles of Green Chemistry. It was shown that by initially capping the temperature at 90ºC, premature decarboxylation can be suppressed. After full conversion to the intermediate 3-carboxycoumarin, the temperature can be increased to 140ºC finalizing the reaction. Ammonium bicarbonate was shown to catalyze both the Green Knoevenagel condensation and the decarboxylation step.

Synthesis and characterization of highly ordered MCM-41 in an alkali-free system and its catalytic activity

1996 ◽  
Vol 38 (1-2) ◽  
pp. 33-37 ◽  
Author(s):  
Xiu S. Zhao ◽  
Gao Q. Lu ◽  
Graeme J. Millar ◽  
Xin S. Li
Keyword(s):  
Catalytic Activity ◽  
Synthesis And Characterization ◽  
Free System ◽  
Mcm 41

Synthesis of 1,2,3–triazole compounds by click chemistry in aqueous medium and evaluation of bactericidal and antitumoral properties.

2021 ◽  
Vol 17 ◽  
Author(s):  
Lucas Lima Zanin ◽  
David Esteban Quintero Jimenez ◽  
Willian Garcia Birolli ◽  
Tiago Venâncio ◽  
Talita Alvarenga Valdes ◽  
...  
Keyword(s):  
Click Chemistry ◽  
Biological Properties ◽  
Antitumoral Activity ◽  
Biological Assays ◽  
Triazole Derivatives ◽  
Optimization Study ◽  
Water As Solvent ◽  
Wide Range ◽  
Screening Study ◽  
High Yields

Background: Triazoles are heterocyclic synthetic compounds that have gained relevance after studies by Sharpless on regioselective methodologies for the synthesis of 1,2,3-triazole derivatives. In addition, they have a wide range of biological properties. Objective: The objective of this study is to develop a synthetic methodology aligned with the principles of click chemistry for the synthesis of 1,2,3-triazole derivatives and verify the profile of these compounds in biological assays. Methods: Initially, a model reaction was selected and an optimization study involving synthetic conditions was carried out. Using the most efficient condition, a series of compounds was developed by the reactions between 2-azido-1-phenylethan-1-one derivatives and terminal alkynes. In sequence, bactericidal and antitumoral assays were performed. Results: It was possible to synthesise ten examples using water as a sustainable solvent, in 1 hour, with good yields of 73–99%, including three compounds described for the first time. Two products presented bactericidal activity, one against the gram-negative Escherichia coli ATCC 25922 and other against the gram-positive Paenibacillus alvei CBMAI 2221. Moreover, other two triazole derivatives presented antitumoral activity for prostate and pancreas cancer cells in this screening study with the bioactivity quantified for compound 1-([1,1'-biphenyl]-4-yl)-2-(4-(p-tolyl)-1H-1,2,3-triazol-1-yl)ethan-1-one (IC50 = 132 µM). Conclusion: Herein, an efficient methodology for the synthesis of 1,2,3-triazole derivatives with high yields and using water as solvent was developed. Furthermore, some compounds presented positive results to bactericidal and antitumoral assays, justifying further exploration of these novel compounds and their biological properties.

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