Bronsted acid-type biosurfactant for heterocyclization: a green protocol for benzopyran synthesis

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84610-84620 ◽  
Author(s):  
Smita T. Morbale ◽  
Swati D. Jadhav ◽  
Madhukar B. Deshmukh ◽  
Suresh S. Patil
Keyword(s):  
Catalytic Amount ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Green Protocol ◽  
Acid Type ◽  
Brönsted Acid

Synthesis of benzopyran from the various salicylaldehydes and cyclic 1,3-diketones using catalytic amount of lemon extract as a green biosurfactant.

“On water” palladium catalyzed diastereoselective boronic acid addition to structurally diverse cyclopropane nitriles

2020 ◽  
Vol 18 (43) ◽  
pp. 8886-8898
Author(s):  
Dwaipayan Das ◽  
Prasun Mukherjee ◽  
Asish R. Das
Keyword(s):  
Boronic Acid ◽  
Aqueous Media ◽  
Catalytic Amount ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Arylboronic Acids ◽  
Acid Addition ◽  
Brönsted Acid ◽  
Diastereoselective Addition ◽  
Palladium Catalyzed

An efficient palladium catalyzed diastereoselective addition of arylboronic acids to complex spirocyclopropyl dinitriles is developed in the presence of a catalytic amount of DBSA as a Brønsted acid surfactant in aqueous media.

scholarly journals Cooperative Brønsted Acid-Type Organocatalysis for the Stereoselective Synthesis of Deoxyglycosides

2016 ◽  
Vol 82 (1) ◽  
pp. 407-414 ◽  
Author(s):  
Carlos Palo-Nieto ◽  
Abhijit Sau ◽  
Ryan Williams ◽  
M. Carmen Galan
Keyword(s):  
Stereoselective Synthesis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Acid Type ◽  
Brönsted Acid

scholarly journals Chiral Brønsted Acids Catalyze Asymmetric Additions to Substrates that Are Already Protonated: Highly Enantioselective Disulfonimide-Catalyzed Hantzsch Ester Reductions of NH–Imine Hydrochloride Salts

Synlett ◽  
2020 ◽  
Vol 31 (17) ◽  
pp. 1707-1712
Author(s):  
Benjamin List ◽  
Vijay N. Wakchaure ◽  
Carla Obradors
Keyword(s):  
Asymmetric Reduction ◽  
Kinetic Studies ◽  
Catalytic Amount ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Iminium Salts ◽  
Catalytic Activation ◽  
Brönsted Acid ◽  
Chiral Brønsted Acids ◽  
Asymmetric Additions

While imines are frequently used substrates in asymmetric Brønsted acid catalysis, their corresponding salts are generally considered unsuitable reaction partners. Such processes are challenging because they require the successful competition of a catalytic amount of a chiral anion with a stoichiometric amount of an achiral one. We now show that enantiopure disulfonimides enable the asymmetric reduction of N–H imine hydrochloride salts using Hantzsch esters as hydrogen source. Our scalable reaction delivers crystalline primary amine salts in great efficiency and enantioselectivity and the discovery suggests potential of this approach in other Brønsted acid catalyzed transformations of achiral iminium salts. Kinetic studies and acidity data suggest a bifunctional catalytic activation mode.

Chickpea Leaf Exudates: A green Bronsted acid type biosurfactant for bis(indole)methanes and bis(pyrazolyl)methanes synthesis

2021 ◽  
Author(s):  
Rupesh C. Patil ◽  
Shashikant A. Damate ◽  
Dnyandev N. Zambare ◽  
Suresh S. Patil
Keyword(s):  
Green Synthesis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Highly Efficient ◽  
Acid Type ◽  
Brönsted Acid

A clean and highly efficient protocol for green synthesis of bis(indole)methanes and bis (pyrazolyl)methanes have been successfully achieved by using a naturally sourced bio-surfactant, chickpea leaf exudates (CLE) as a...

scholarly journals Helicene synthesis by Brønsted acid-catalyzed cycloaromatization in HFIP [(CF3)2CHOH]

2021 ◽  
Vol 17 ◽  
pp. 396-403
Author(s):  
Takeshi Fujita ◽  
Noriaki Shoji ◽  
Nao Yoshikawa ◽  
Junji Ichikawa
Keyword(s):  
Bond Formation ◽  
Catalytic Amount ◽  
Trifluoromethanesulfonic Acid ◽  
Higher Order ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Facile Synthesis ◽  
Brönsted Acid ◽  
Acid Catalyzed

A facile synthesis of carbo- and heterohelicenes was achieved via tandem cycloaromatization of bisacetal precursors, which were readily prepared through C–C bond formation by Suzuki–Miyaura coupling. This cyclization was efficiently realized by a catalytic amount of trifluoromethanesulfonic acid (TfOH) in a cation-stabilizing solvent, 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP), which readily allowed gram-scale syntheses of higher-order helicenes, double helical helicenes, and heterohelicenes.

scholarly journals Stereoselective Synthesis of Iminosugar 2-Deoxy(thio)glycosides from Bicyclic Iminoglycal Carbamates Promoted by Cerium(IV) Ammonium Nitrate and Cooperative Brønsted Acid-Type Organocatalysis

2020 ◽  
Vol 85 (7) ◽  
pp. 5038-5047 ◽  
Author(s):  
Irene Herrera-González ◽  
Elena M. Sánchez-Fernández ◽  
Abhijit Sau ◽  
Cristina Nativi ◽  
José M. García Fernández ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Stereoselective Synthesis ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Acid Type ◽  
Brönsted Acid ◽  
Cerium Iv Ammonium Nitrate

scholarly journals Acid-free extraction of cellulose type I nanocrystals using Brønsted acid-type ionic liquids

2016 ◽  
Vol 2 (2) ◽  
pp. 65-75 ◽  
Author(s):  
Jevgenij Lazko ◽  
Tangi Sénéchal ◽  
Arthur Bouchut ◽  
Yoann Paint ◽  
Lisa Dangreau ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Type I ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Acid Type ◽  
Brönsted Acid

scholarly journals Brønsted acid-mediated cyclization–dehydrosulfonylation/reduction sequences: An easy access to pyrazinoisoquinolines and pyridopyrazines

2017 ◽  
Vol 13 ◽  
pp. 428-440 ◽  
Author(s):  
Ramana Sreenivasa Rao ◽  
Chinnasamy Ramaraj Ramanathan
Keyword(s):  
Ambient Temperature ◽  
Carbonyl Group ◽  
Catalytic Amount ◽  
Easy Access ◽  
Primary Amines ◽  
Synthetic Approach ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
One Pot ◽  
Brönsted Acid

An efficient and alternative synthetic approach has been developed to prepare various N-(arylethyl)piperazine-2,6-diones from 4-benzenesulfonyliminodiacetic acid and primary amines using carbonyldiimidazole in the presence of a catalytic amount of DMAP at ambient temperature. Piperazine-2,6-diones are successfully transformed to pharmaceutically useful pyridopyrazines or pyrazinoisoquinolines and ene-diamides via an imide carbonyl group activation strategy using a Brønsted acid. Subsequent dehydrosulfonylation reactions of the ene-diamides, in a one pot manner, smoothly transformed them to substituted pyrazinones. A concise synthesis of praziquantel (1) has also been achieved through this method.

Cooperative Brønsted Acid-Type Organocatalysis:  Alcoholysis of Styrene Oxides

2008 ◽  
Vol 10 (8) ◽  
pp. 1513-1516 ◽  
Author(s):  
Torsten Weil ◽  
Mike Kotke ◽  
Christian M. Kleiner ◽  
Peter R. Schreiner
Keyword(s):  
Bronsted Acid ◽  
Brønsted Acid ◽  
Acid Type ◽  
Brönsted Acid
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