An Efficient One‐Pot Synthesis of 7,7‐Dimethyl‐2‐(2‐oxo‐2H‐chromen‐3‐yl)‐4‐aryl‐7,8‐dihydroquinolin‐5(6H)‐one Derivatives Using Chitosan–SO₃H as Biodegradable Organocatalyst

Abstract

Chitosan sulfonic acid (CS–SO3H), a biodegradable green catalyst, was found to be an impressive system for one‐pot four‐component reaction of different aromatic aldehydes, 3‐acetylcoumarin, dimedone, and ammonium acetate leading to 7,7‐dimethyl‐2‐(2‐oxo‐2H‐chromen‐3‐yl)‐4‐aryl‐7,8‐dihydroquinolin‐5(6H)‐one under solvent‐free condition. This methodology produces diverse superiorities such as operational simplicity, short reaction time, and high yield. Further, the catalyst can be reused for four times without any noticeable decrease in the catalytic activity.

SiO2‐POCl2 nanoparticles promoted the synthesis of novel structure of 2,3‐dihydrooxazole derivatives

“…Thus, the synthesis of 2,3‐dihydrooxazoles via a simple procedure through the multicomponent reaction is in demand. In this communication, in continuation of our works on heterocyclic synthesis, we disclose the first three‐component reaction of ethyl 3‐phenyl glycidate, aniline derivatives, and DMF to produce a variety of ethyl 4‐phenyl‐3‐aryl‐2,3‐dihydrooxazole‐5‐carboxylates using silica‐POCl 2 as an efficient promoter (Scheme ).…”

Application of Cyclohexane‐1,3‐diones in the Synthesis of Six‐Membered Nitrogen‐Containing Heterocycles

“…This protocol proved useful for the scale up synthesis of coumarin substituted dihydroquinolinone derivatives (Scheme 39). [82] …”

“…This protocol proved useful for the scale up synthesis of coumarin substituted dihydroquinolinone derivatives (Scheme 39). [82] The synthesis of natural product based polycyclic pyridine derivatives 52 has also been developed via the Friedlander reaction and further evaluation for potential anti-tuberculosis agents. The reaction basically proceeded by the trifluoroacetic acid (TFA) catalysed condensation of the dimedone with 2amino benzophenones under microwave-assisted reaction conditions.…”

“…Pyridine‐containing N ‐heterocycles are developed by electrochemically tempted condensation of various aromatic aldehydes, cyclohexane‐1,3‐diones and 6‐amino uracil, [79] by four‐component bicyclization reactions [80] . Moreover, these compounds are also prepared from cyclohexan‐1,3‐dione derivatives in the presence of various recoverable catalysts such as tetrapropylammonium bromide, [81] biodegradable organocatalyst i.e chitosan‐SO 3 H, [82] CeCl 3 .7H 2 O‐NaI, [78] diphenylammonium triflate [83] …”

“…[78] Pyridine-containing N-heterocycles are developed by electrochemically tempted condensation of various aromatic aldehydes, cyclohexane-1,3-diones and 6-amino uracil, [79] by four-component bicyclization reactions. [80] Moreover, these compounds are also prepared from cyclohexan-1,3-dione derivatives in the presence of various recoverable catalysts such as tetrapropylammonium bromide, [81] biodegradable organocatalyst i.e chitosan-SO 3 H, [82] CeCl 3 .7H 2 O-NaI, [78] diphenylammonium triflate. [83] Quinolones are also significant class of nitrogen-containing heterocycles that display fascinating biological activities, such as antiinflammatory, anticancer, selective progesterone, glucocorticoid receptor modulators, and blue luminophores.…”