scholarly journals Microwave-Assisted Three-Component “Catalyst and Solvent-Free” Green Protocol: A Highly Efficient and Clean One-Pot Synthesis of Tetrahydrobenzo[b]pyrans

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Sougata Santra ◽  
Matiur Rahman ◽  
Anupam Roy ◽  
Adinath Majee ◽  
Alakananda Hajra

A green and highly efficient method has been developed for the one-pot synthesis of tetrahydrobenzo[b]pyrans via a three-component condensation of aldehydes, 1,3-cyclic diketones, and malononitrile under MW irradiation without using any catalyst and solvent. This transformation presumably occurs by a sequential Knoevenagel condensation, Michael addition, and intramolecular cyclization. Operational simplicity, solvent and catalyst-free conditions, the compatibility with various functional groups, nonchromatographic purification technique, and high yields are the notable advantages of this procedure.

2021 ◽  
Vol 76 (2) ◽  
pp. 85-90
Author(s):  
Abdolkarim Zare ◽  
Manije Dianat

Abstract A highly efficient and green protocol for the synthesis of pyrimido[4,5-b]quinolines has been described. The one-pot multicomponent reaction of dimedone with arylaldehydes and 6-amino-1,3-dimethyluracil in the presence of N,N-diethyl-N-sulfoethanaminium chloride ([Et3N–SO3H][Cl]) as an ionic liquid (IL) catalyst under solvent-free conditions afforded the mentioned compounds in high yields and short reaction times. Our protocol is superior to many of the reported protocols in terms of two or more of these factors: the reaction times, yields, conditions (solvent-free versus usage of organic solvents), temperature and catalyst amount.


2016 ◽  
Vol 40 (12) ◽  
pp. 722-726 ◽  
Author(s):  
Afshin Yazdani-Elah-Abadi ◽  
Razieh Mohebat ◽  
Mehrnoosh Kangani

A highly efficient one-pot, two-step microwave-assisted procedure was applied for the rapid and green synthesis of benzo[a]phenazine annulated heterocyclic ring systems from the three- or four-component condensation reactions of 2-hydroxynaphthalene-1,4-dione, o-phenylenediamine, aromatic aldehydes and 1,3-indandione using L-proline as a bifunctional organocatalyst in water. This new procedure has a number of advantages such as high yields, very short reaction times, operational simplicity, simple work-up procedures and avoidance of hazardous or toxic catalysts and organic solvents. Moreover, the catalyst can be recovered and reused several times without much loss of its performance.


2015 ◽  
Vol 68 (10) ◽  
pp. 1529 ◽  
Author(s):  
Mehdi Rimaz

Two efficient regioselective approaches for the one-pot synthesis of 3-arylpyridazino[4,3-c]quinolin-5(6H)-one derivatives are reported, by the three-component reaction of arylglyoxal monohydrates, quinoline-2,4-diol, and hydrazinium dihydrochloride or hydrazine hydrate in ethanol and pyridine. In ethanol, the reactions were catalyzed by 1,4-diazobicyclo[2,2,2]octane. The features of both procedures are high regioselectivity, mild reaction conditions, good to high yields, and operational simplicity.


2013 ◽  
Vol 6 (1) ◽  
pp. 150-156
Author(s):  
Pramod S. Kulkarni ◽  
Dasharath D. Kondhare ◽  
Ravi Varala ◽  
Pudukulathan K. Zubaidha

Abstract Calcium hydroxide was found to be an efficient mild base for the one-pot synthesis of curcumin and its analogues obtained by condensation of one equivalent of acetyl acetone with two equivalents of corresponding aromatic aldehyde. The present protocol offers various advantages such as high yields, inexpensive easily available mild base, easy workup and eco-friendly method.


2014 ◽  
Vol 41 (11) ◽  
pp. 8057-8065 ◽  
Author(s):  
Jasem Aboonajmi ◽  
Malek Taher Maghsoodlou ◽  
Nourallah Hazeri ◽  
Mojtaba Lashkari ◽  
Mehrnoosh Kangani

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