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A new three‐component domino reaction for the synthesis of 2‐amino‐6‐aryl‐5‐(phenylamino)‐3,7‐dihydro‐4H‐pyrrolo[2,3‐d]pyrimidin‐4‐one derivatives 4 using acetic acid as catalyst has been established. The reaction was performed in aqueous media using readily available and inexpensive 2,6‐diaminopyrimidin‐4(3H)‐one 1, 2,2‐dihydroxy‐1‐arylethan‐1‐one 2 and aniline 3 as substrates. The simple and efficient one‐pot three‐component approach, inexpensive catalyst, green reaction media, make the present methodology a good synthetic procedure. [ABSTRACT FROM AUTHOR]

A flexible and efficient three-component reaction has been established for the synthesis of bioactive 1,6-naphthyridine-2,5-diones by using low-cost and readily accessible aminopyridinones, aromatic aldehydes, and Meldrum's acid as starting materials. The main advantage of this synthetic method is that the yields of the resulting 1,6-naphthyridine-2,5-dione derivatives under ultrasound irradiation in water with acetic acid as catalyst are higher than those from the classical-heating method. The probable reaction mechanism indicates that the process involves a Knoevenagel condensation, Michael addition, and cyclization sequence. [ABSTRACT FROM AUTHOR]

A series of new pyrano[4,3‐b]quinoline‐1,9(5H)‐dione derivatives were synthesized via one‐pot three‐component reaction using 6‐methyl‐4‐(arylamino)‐2H‐pyran‐2‐ones, aldehydes, and 1,3‐cyclohexanediones as substrates. The application of 4‐methylbenzenesulfonyl chloride activated the hydroxyl group of pyranone and avoided the forming of ring opening product. The reaction proceeds smoothly and gives biological and pharmacological active substituted pyrano[4,3‐b]quinoline‐1,9(5H)‐dione derivatives with good to excellent yields under green conditions. A plausible mechanism for the domino process is proposed. [ABSTRACT FROM AUTHOR]

An efficient approach for the synthesis of 2,6‐dimethyl‐1,3‐diarylpyrano[4,3‐b]pyrrol‐4(1H)‐one derivatives has been established. The reaction was performed in aqueous media using readily available and inexpensive 6‐methyl‐4‐(phenylamino)‐2H‐pyran‐2‐one and nitroolefin as substrates. The present methodology shows many attractive advantages, such as using water as green reaction media, inexpensive and environmentally friendly acetic acid as catalyst, easy work‐up procedure, and good to excellent yields. [ABSTRACT FROM AUTHOR]

An efficient four‐component approach for the synthesis poly‐substituted pyrano[3,2‐c]pyridones and spiro[indoline‐3,4′‐pyrano[3,2‐c]pyridine]‐2,5′(6′H)‐diones in water has been established. During the reaction, the products were readily achieved through one‐pot two‐step reaction using solid acid as catalyst. The advantages of atom and step economy, the recyclability of heterogeneous solid acid catalyst, easy workup procedure, and the wide scope of substrates make the reaction a powerful tool for assembling pyrano[3,2‐c]pyridone skeletons of chemical and medical interest. [ABSTRACT FROM AUTHOR]

A multicomponent two-step strategy for the synthesis of polysubstituted pyrrolo[3,2-c]pyridin-4-one derivatives has been described. The reactions can be readily performed by mixing inexpensive starting materials using two-step methods under mild conditions, and the products can be easily obtained from the mother liquid without any further treatment. Moreover, the solid acid catalyst can be circulated at least 6 times without obvious deactivation. Furthermore, a mechanism for the reaction process has been proposed. Overall the bond forming efficiency, the use of green solvent as the reaction medium, recyclability of the solid acid catalyst, easy work-up/purification, and a wide substrate scope make this method highly attractive to assemble heterocyclic scaffolds. [ABSTRACT FROM AUTHOR]

A solid acid-catalyzed cascade reaction of condensation/intermolecular nucleophilic addition/intramolecular cyclization, esterification and amination has been developed to rapidly construct complex polysubstituted indole compounds. This one-pot, three-step five-component cascade reaction affords a series of 2-(4-oxo-1,2-diphenyl-4,5,6,7-tetrahydro-1 H -indol-3-yl) acetamide derivatives with good yield under mild conditions. The present procedure exhibited some attractive features, including inexpensive and easy available reagents, large substrate scope, separable intermediate products, recyclable solid acid catalyst, and more importantly, it can be conveniently performed by simple one-pot three-step procedure, involving the sequential mixture of 3-(arylamino)cyclohex-2-en-1-ones, 2,2-dihydroxy-1-arylethan-1-ones, meldrum acid, and alcohols, anilines in the of solid acid at 80 °C. Significantly, this strategy not only expands the application range of solid acid, but also provides a series of 2-(4-oxo-1,2-diphenyl-4,5,6,7-tetrahydro-1 H -indol-3-yl)acetate/acetamide derivatives. [Display omitted] • A one-pot three-step reaction for the synthesis of indol-3-yl acetamides has been reported. • The reaction can be performed using recyclable solid acid as catalyst in water. • This chemistry provides a strategy to synthesize indol-3-yl acetates and indol-3-yl acetamides. [ABSTRACT FROM AUTHOR]

• An efficient and green strategy for synthesis of 1,6-naphthyridines has been established. • The 1,6-naphthyridines are obtained catalyzed by solid acid under ultrasonic irradiation. • The ultrasonic irradiation as thermal and kinetic energy source shorten reaction time and heighten yield. An efficient and highly eco-friendly approach to poly-substituted 1,6-naphthyridine derivatives with good to excellent yield has been reported using simple and readily available 4-aminopyridinone, aromatic aldehyde or isatin, and 1,3-cyclohexanedione as substrates. The method features low-cost and readily accessible starting materials, green ultrasonic irradiation in water, recycle heterogeneous solid acid catalyst, broad substrate scope as well as simple one-pot operation make this strategy highly attractive. Mechanistic studies indicate that this transformation involves Knoevenagel condensation, Michael addition, and cyclization sequence. [ABSTRACT FROM AUTHOR]

• A new domino approach for synthesis of pyrrolo[3,2- c pyridin-4-ones has been established. • The one-pot two-step four component strategy makes the reaction attractive. • The remarkable feature of the process is the formation of five C–N, C–C bonds initiated by sole acetic acid. A direct and metal-free access toward poly-substituted pyrrolo[3,2- c pyridin-4-one and its analogues have been established through a simple four-component, two-step reaction of 4-hydroxy-6-methyl-2 H -pyran-2-one, two amine molecules, and β -nitrostyrenes. The reaction allows the formation of five different C–N, C–C bonds by the multiple bond cleavage only using acetic acid as catalyst and solvent. The advantages of broad substrate scope, efficient and metal-free reaction conditions, inexpensive and readily available starting materials as well as simple one-pot two-step operation, make the strategy highly attractive. This transformation in acetic acid resulted in the rapid establishment of functional bioactive poly-substituted pyrrolo[3,2- c pyridin-4-one derivatives. [ABSTRACT FROM AUTHOR]

A novel procedure for the one-pot condensation of aminopyrazoles, aldehydes, and cycloketones is developed using carbon functionalized with sulfonic acid groups as solid catalyst. [ABSTRACT FROM AUTHOR]