Pyridine-2-carboxylic acid as an effectual catalyst for rapid multi-component synthesis of pyrazolo[3,4-b]quinolinones

Abstract

Green synthesis of pyrazolo[3,4-b]quinolinones was designed using bioproduct pyridine-2-carboxylic acid (P2CA) as a green and efficient catalyst.

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

“…The use of potassium tert ‐butoxide in microwave conditions produces another tricyclic product pyrazoloquinolizinones 67 (Scheme 52). [212] Recently in 2020, the similar reaction developed for pyrazoloquinolinones using pyridine‐2‐carboxylic acid (P2CA) as green catalyst comparably at milder reaction conditions [213] …”

“…[212] Recently in 2020, the similar reaction developed for pyrazoloquinolinones using pyridine-2-carboxylic acid (P2CA) as green catalyst comparably at milder reaction conditions. [213] Scheme 47. Ionic liquid promoted tetrahydrobenzo[a] acridinones under metal-free conditions.…”

Efficient one pot preparation of novel 1-oxo-3-aryl-1,5-dihydrobenzo[4,5]imidazo[1,2-a]pyridine-2-carboxylic acid derivatives in a green solvent

“…14 Because the benzo [4,5]imidazo [1,2-a]pyridine scaffold show interesting biological activities, the synthesis of this group of compounds has been realised via several routes, including cycloaddition reactions, 6,9,15 condensation reactions, [16][17][18] multicomponent reactions, 10,[19][20][21][22][23] and multistep approaches. 5,[24][25][26] Also, metallic and non-metallic catalysts, [27][28][29][30] microwave irradiation, 31 and a series of transition metal catalysts have been used for the preparation of these compounds. 1,32 No doubt, the existing methods are useful, but also possess certain limitations such as an extended reaction time, special apparatus, high temperature, expensive catalysts, toxic solvents, and tedious workup processes.…”

Crystal structure and Biological evolution of 5-bromothiophene based 3,4-dihydropyrimidin-2-(1H)-thi(ones)

“…For this purpose, we decided to utilise the Biginelli reaction to develop 5-bromothiophene based 3,4-dihydropyrimidin-2-(1H)thi(ones). Like many other reactions, [19][20][21][22][23][24][25] Biginelli reaction is a three-component reaction involving the condensation of an aldehyde, urea and a β-ketoester under acidic conditions. 26 In our previous work, we synthesised 5-bromothiophene based 1,4-dihydropyridine via solvent-free protocol for CAN (Ceric ammonium nitrate) catalysed Hantzsch reaction.…”