A Convenient Synthesis of 1,5-Fused 1,2,4-Triazoles from N-Arylamidines via Chloramine-T Mediated Intramolecular Oxidative N–N Bond Formation

Synthesis ◽  
2019 ◽  
Vol 51 (20) ◽  
pp. 3883-3890
Author(s):  
Ashish Bhatt ◽  
Rajesh K. Singh ◽  
Ravi Kant ◽  
Bhupendra K. Sarma

A convenient synthesis of 1,5-fused 1,2,4-triazoles from readily available N-arylamidines is reported. The reaction is efficiently promoted by chloramine-T to afford the desired products mostly in high yields and in relatively short time, through direct metal-free oxidative N−N bond formation. The mild nature of the synthesis and short reaction time are notable advantages of the developed protocol. This protocol is effective toward various substrates having different functionalities.

2017 ◽  
Vol 41 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Sethurajan Ambethkar ◽  
Muthalu Vellimalai ◽  
Vediappen Padmini ◽  
Nattamai Bhuvanesh

The regioselective synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives via amination (C–N) and intramolecular cyclization (C–S) reactions in the presence of molecular iodine has been reported. This method is base and metal free and features inexpensive catalysts, with a simple procedure and a short reaction time.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Naser Montazeri ◽  
Taghva Noghani ◽  
Mona Ghorchibeigy ◽  
Rozita Zoghi

Pentafluoropropionic acid (PFPA) efficiently catalyzes the one-pot, three-component reaction of aromatic aldehyde, malononitrile, and dimedone to yield tetrahydrobenzo[b]pyran derivatives in high yields. This method is of great value because of its easy processing, short reaction time, environmentally, and high yields.


2009 ◽  
Vol 2009 (10) ◽  
pp. 638-641 ◽  
Author(s):  
Xufeng Lin ◽  
Jun Wang ◽  
Fangxi Xu ◽  
Yanguang Wang

A highly efficient method for the C–N bond formation via 2 mol% of molecular iodine-catalysed amidation reaction of benzylic and allylic alcohols with carboxamides or sulfonamides in MeCN is described, giving the corresponding substituted amides and allylic amides in moderate to excellent yields. The significan features of the procedure include mild and metal-free reaction conditions, operational simplicity, inexpensive reagents, short reaction time, and good yields.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Xiao-chuan Jia ◽  
Jing Li ◽  
Yu Ding ◽  
Bin Zhang ◽  
Na Wang ◽  
...  

A robust, facile, and solvent-free route for the three-component synthesis of 2H-indazolo[2,1-b]phthalazine-triones in the presence of a catalytic amount ofp-toluene sulfonic acid utilizing grinding has been developed. Short reaction time, simple operation, and high yields are the advantages of this protocol.


RSC Advances ◽  
2020 ◽  
Vol 10 (59) ◽  
pp. 36031-36041
Author(s):  
Gopinadh Meera ◽  
K. R. Rohit ◽  
Salim Saranya ◽  
Gopinathan Anilkumar

Microwave assisted synthesis of N-heterocycles with short reaction time, high yields and high product purities along with a decrease in the rate of by-product formation.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Amulrao Borse ◽  
Mahesh Patil ◽  
Nilesh Patil ◽  
Rohan Shinde

An expeditious, one-pot method for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones using a mixture of phosphorus pentoxide-methanesulfonic acid (Eaton’s reagent) at room temperature under solvent-free conditions is described. The salient features of this method include short reaction time, green aspects, high yields, and simple procedure.


2010 ◽  
Vol 64 (6) ◽  
Author(s):  
Selvaraj Roopan ◽  
Fazlur Nawaz Khan

AbstractFor the first time, synthesis of AB ring core of camptothecin synthons such as (2-chloroquinolin-3-yl)methanols (Va-Vg) using zinc oxide nanoparticles is reported. The desired attractive products were obtained in high yields, short reaction time, using a simple work-up procedure with the purification of products by non-chromatographic methods.


2021 ◽  
Author(s):  
Ritiele Heck ◽  
Thiago Anjos ◽  
Maira R Giehl ◽  
Ricardo F Schumacher ◽  
Benhur Godoi

Flavone and analogues represent an important class of biologically and pharmacologically active substances commonly found in the composition of diverse plants as part of the class of secondary metabolites. Herein, we have demonstrated an efficient and regioselective synthetic strategy for the preparation of functionalized flavones through sequential demethylation/6-endo-dig intramolecular cyclization of propyn-1-ones, using catalytic amounts of base in the presence of a thiol, by employing NMP as the solvent. The reactions proceeded smoothly under transition-metal-free and open to air conditions, furnishing the desired six-membered heterocycles in moderate to excellent yields, in short reaction time.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maryam Kamalzare ◽  
Mohammad Reza Ahghari ◽  
Mohammad Bayat ◽  
Ali Maleki

AbstractRecently magnetic nanocatalyst has attracted considerable attention because of its unique properties, including high performance, easy separation from the reaction mixture, and recyclability. In this study, a novel magnetic bionanocomposite was synthesized with chitosan and tannic acid as a natural material. The synthesized bionanocatalyst was characterized by essential analysis. Fe3O4@chitosan-tannic acid as a heterogeneous nanocatalyst was successfully applied to synthesize pyranopyrazole and its derivatives by a one-pot four-component reaction of malononitrile, ethyl acetoacetate, hydrazine hydrate, and various aromatic aldehyde. At the end of the reaction, the nanocatalyst was separated from the reaction mixture and was reused several times with no significant decrease in its catalytic performance. Simple purification of products, the ability for recovering and reusing the nanocatalyst, eco-friendliness, high yields of pure products, mild reaction conditions, short reaction time, non-toxicity, economically affordable are some of the advantages of using the fabricated nanocatalyst in the synthesis of pyranopyrazole.


Synthesis ◽  
2019 ◽  
Vol 52 (05) ◽  
pp. 727-734 ◽  
Author(s):  
Farnaz Jafarpour ◽  
Mohammad Asadpour ◽  
Meysam Azizzade ◽  
Mehran Ghasemi ◽  
Saideh Rajai-Daryasarei

A mild, scalable iodine-mediated oxidative cross-coupling reaction of arylhydrazines and thiols for construction of thioethers (sulfides) in the absence of any transition metals or photocatalysts is disclosed. A variety of unsymmetrical diaryl sulfides with broad substrate scope both on thiols and hydrazines were synthesized in high yields in water at room temperature. Furthermore, to demonstrate the utility of the protocol, the above C–S bond formation was applied in the synthesis of the key structure of vortioxetine as an antidepressant drug. The gram-scale outcome also added to the potential utility of this protocol.


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