KHSO4 Catalysed Pechmann Condensation Under Solvent-free Conditions

2005 ◽  
Vol 2005 (8) ◽  
pp. 486-487 ◽  
Author(s):  
Jinhua Qian ◽  
Jishuan Suo
Keyword(s):  
Cost Effective ◽  
Solvent Free ◽  
Acid Catalysts ◽  
Pechmann Condensation ◽  
Solvent Free Conditions ◽  
Substituted Coumarins

KHSO4 is used as an alternative to conventional acid catalysts in the Pechmann condensation of phenols with β-ketoesters leading to the formation of substituted coumarins. The method is simple, cost-effective, solvent-free and gives good isolated yields.

scholarly journals One-Pot Synthesis of Coumarins Unsubstituted on the Pyranic Nucleus Catalysed by a Wells–Dawson Heteropolyacid (H6P2W18O62)

2018 ◽  
Author(s):  
Yu-Feng Sun ◽  
Jia-Meng Liu ◽  
Jing Sun ◽  
Ya-Tao Huang ◽  
Jia Lu ◽  
...  
Keyword(s):  
Solvent Free ◽  
Catalytic Method ◽  
One Pot ◽  
Phenol Derivatives ◽  
Pechmann Condensation ◽  
One Pot Synthesis ◽  
Solvent Free Conditions ◽  
Substituted Coumarins

The development of a method to produce coumarins unsubstituted on the pyranic nucleus catalyzed from Wells–Dawson heteropolyacid (H6P2W18O62), phenol derivatives and ethyl 3,3-diethoxypropionate using Pechmann condensation under solvent-free conditions is described. This catalytic method was also applied successfully to synthesize various substituted coumarins, including the corresponding phenols and ethyl 3,3-diethoxypropionate. This work provides a novel, cheaper and safer way to syhthesize coumarins unsubstituted on the pyranic nucleus.

scholarly journals Barium Dichloride as a Powerful and Inexpensive Catalyst for the Pechmann Condensation without Using Solvent

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Saeed Khodabakhshi
Keyword(s):  
Green Chemistry ◽  
Organic Solvents ◽  
Condensation Reaction ◽  
Reaction Times ◽  
Solvent Free ◽  
Coumarin Derivatives ◽  
Inexpensive Method ◽  
Keto Esters ◽  
Pechmann Condensation ◽  
Solvent Free Conditions

Various coumarin derivatives have been efficiently synthesized via barium dichloride-catalyzed Pechmann condensation reaction of various phenols and β-keto esters under solvent-free conditions. This novel and inexpensive method has advantages such as short reaction times, excellent product yields, and avoidance of organic solvents in agreement with green chemistry principles.

Selectfluor™: A simple and efficient catalyst for the synthesis of substituted coumarins under solvent-free conditions

2006 ◽  
Vol 43 (2) ◽  
pp. 477-479 ◽  
Author(s):  
B. Sunil Kumar ◽  
Y. Thirupathi Reddy ◽  
P. Narsimha Reddy ◽  
P. S. Kumar ◽  
B. Rajitha
Keyword(s):  
Solvent Free ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Substituted Coumarins

scholarly journals Dioxane dibromide mediated bromination of substituted coumarins under solvent-free conditions

2012 ◽  
Vol 8 ◽  
pp. 323-329 ◽  
Author(s):  
Subrata Kumar Chaudhuri ◽  
Sanchita Roy ◽  
Sanjay Bhar
Keyword(s):  
Solvent Free ◽  
Electronic Nature ◽  
Solvent Free Conditions ◽  
Substituted Coumarins

An efficient solvent-free protocol for regioselective bromination of substituted coumarins has been developed by using dioxane dibromide as the solid brominating agent. The efficacy of the solvent-free protocol has been established. The effects of the electronic nature and location of the substituents on the outcome of the reaction have been rationalized with a proposed mechanism.

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