Search

A strategy for catalyst-free domino reaction of 4-aminopyridin-2(1H)-ones, arylglyoxal hydrates and different 1,3-dicarbonyl compounds in water has been established. The mild and efficient procedure afforded pyrrolo[3,2-c]pyridine derivatives with 76-94% yields after simple crystallization. The present procedure shows promising characteristics, such as readily available starting materials, the use of water as reaction media, simple and efficient one-pot operation, and avoiding the need for any hazardous or expensive catalysts., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The mesoporous silica SAB‐15 material and a series of nano‐composite bimetal oxides‐SBA‐15 materials are synthesized. The oxidation of various benzyl alcohols to aromatic aldehydes has been studied using nano‐composite bimetal oxides‐SBA‐15 materials as catalysts in air. The results indicate that the CrMnOx‐SBA‐15 material can promote the oxidation of benzyl alcohols to aromatic aldehydes with excellent yields smoothly. The microstructure and morphology of SBA‐15 and CrMnOx‐SBA‐15 materials are characterized by SEM, TEM, XRD and nitrogen adsorption/desorption isotherms, respectively. In addition, the UHRTEM images, EDS image mapping, and the X‐ray photoelectron spectroscopy (XPS) of CrMnOx‐SBA‐15 material also are characterized, which indicate the structure of the catalyst is advantageous to improve its catalytic activity. [ABSTRACT FROM AUTHOR]

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 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]

Abstract: A series of poly‐substituted pyrano[2,3–d]pyrimidine derivatives have been synthesized using solid acid as catalyst in water. The poly‐substituted pyrano[2,3–d]pyrimidines are important structural motifs in organic and biological research. The present procedure shows many attractive advantages, such as the operational simplicity, highly efficiency and recyclability of heterogeneous catalyst, and highly yields of desired products. A probable mechanism was proposed for accounting the domino reaction. [ABSTRACT FROM AUTHOR]

An efficient domino approach for the synthesis of new pyrano[4,3- b ]pyrazolo[4,3- e ]pyridin-5(1 H )-one derivatives has been developed using reusable sulfonic organic resin as catalyst in water. The unique feature of sulfonic organic resin makes the formation of pyrano[4,3- b ]pyrazolo[4,3- e ] pyridin-5(1 H )-ones be possible, and avoids generating ring opening products. The plausible mechanism for this domino reaction is proposed. [ABSTRACT FROM AUTHOR]

A series of furo[2,3- d ]pyrimidine derivatives were synthesized via the [3+2] cyclization of pyrimidine-4,6-diol and a variety of nitroolefins at catalyst-free conditions. The reaction is easy to perform simply mixing inexpensive starting materials in water under conventional heating at 90 °C. The reaction proceeds at a fast speed within 1.5–2 h and gives the high biological and pharmacological active substituent furo[2,3- d ]pyrimidine derivatives with good to high yields. Mechanism of formation of these furo[2,3- d ]pyrimidine derivatives are also proposed. [ABSTRACT FROM AUTHOR]

An efficient, high yielding method has been developed for the synthesis of diversity tetrahydro-4 H -indol-4-one derivatives via a three component, one pot domino reaction from cyclohexane-1,3-diones, amines and nitrostyrenes using carbon functionalized with sulfonic acid group carbonaceous material as catalyst for the first time. The reaction was carried out in water, affording good to excellent yields in short time. The advantages of atom and step economy, green, and scope make this reaction a powerful tool for assembling heterocyclic scaffolds of general chemical and biomedical interest. [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]