Microwave-Assisted Improved Synthesis of Pyrrolo[2,3,4-kl]acridine and Dihydropyrrolo[2,3,4-kl]acridine Derivatives Catalyzed by Silica Sulfuric Acid

Abstract

An improved synthesis of multifunctionalized pyrrolo[2,3,4-kl]acridine derivatives with different substituted patterns using silica sulfuric acid (SSA) as a heterogeneous catalyst under microwave irradiation conditions was developed. The reaction could be conducted by using readily available and inexpensive substrates within short periods of 12–15 min. under microwave irradiation. Compared with the conventional methods, the remarkable advantages of this method are milder reaction conditions, operational simplicity, higher yields, short reaction times, and an environmentally friendly procedure.

One-Pot Synthesis of 3-Functionalized 4-Hydroxycoumarin under Catalyst-Free Conditions

“…Compared with traditional methods, this method has the advantages of higher yields, shorter reaction time, mild reaction conditions and environmentally friendliness. To date, a large number of organic reactions can be carried out under microwave irradiation conditions [ 17 , 18 , 19 , 20 ].…”

An Efficient Synthesis of Acenaphtho[1,2-b]indole Derivatives via Domino Reaction

“…Consequently, domino reactions have often been used for the construction of complex heterocycles [ 23 , 24 , 25 , 26 , 27 , 28 ]. As part of our program to develop new methods for the construction of important heterocycles by domino reactions [ 29 , 30 , 31 , 32 ], we report herein an efficient synthesis of acenaphtho[1,2- b ]indole derivatives via a domino reaction using l -proline as the catalyst.…”

A Green Approach for the One‐Pot, Three‐Component Synthesis of 2‐Arylpyrroloacridin‐1(2H)‐Ones using Lactic Acid as a Bio‐based Catalyst under Solvent‐Free Conditions

“…Acridines have been synthesized using several methods, of which many have utilized the Haunzch reaction of dimedone, aldehyde, and aniline or ammonium acetate . Some of the pyrroloacridines were produced by the reaction between isatins and enaminones, for example, with refluxing in toluene in the presence of L‐proline as catalyst, using CAN in EtOH under ultrasound irradiation, using silica sulfuric acid (SSA) as catalyst under microwave irradiation at 110°C, and with refluxing in AcOH under O 2 and catalyzed by I 2 . These reactions suffer from certain drawbacks, including hard reaction conditions and the use of volatile solvents.…”