A catalyst- and solvent-free protocol for the sustainable synthesis of fused 4<i>H</i>-pyran derivatives

Khan, Md. Musawwer; Shareef, Sumbulunnisan; Saigal, Saigal; Sahoo, Subash Chandra

doi:10.1039/c9ra04370e

Cited by 16 publications

(5 citation statements)

References 48 publications

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“…Pyran [43][44][45] nucleus is found in natural products and show plethora of bioactivities like antioxidant, antimitotic, anticancer, antibacterial, antirheumatic, chk 1 inhibitor, antitubercular, antiinflammatory activities. [46][47][48][49][50] Such a widespread medicinal and biological profile makes them interesting candidates for medicinal chemists.…”

Section: Humic Acid In Functionalized Pyran Synthesismentioning

confidence: 99%

Humic Acid: A Promising and Green Bioorganic Catalyst in Organic Syntheses

Swaraj Acharya,

Bhusan Parida

2024

ChemistrySelect

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The growing pollution and threat to the environment demand green synthetic methods. Green chemistry mainly focuses on minimizing the waste and utilization of green solvents, energy sources, and catalysts and prefers one‐pot reactions. In this context, humic acid (HA), a natural bioorganic catalyst found in rivers, peat coal and sewage; is a high molecular weight macromolecule containing multifunctional groups, mainly contains quinone, phenolic OH, and COOH groups which make it acidic and activate carbonyl groups by protonation. Owing to its green aspect such as biodegradability, recyclability and reusability, humic acid is considered as sustainable bioorganic catalyst which meets the criteria for industrial requirements. The HA is mild acidic in nature, thus many functional groups tolerate in the HA catalyzed reactions. After few initial reports in 2001 and 2009, the HA catalyzed reactions gained much attention by the organic synthetic community from 2019 in aldol condensation, Knoevenagel condensation, Claisen‐Schmidt reaction, Michael addition, Strecker synthesis, tetrazole synthesis, Hantzsch dihydropyridine synthesis, hydrosilylation of terminal alkenes, hydrogenation, α‐aminophosphonate synthesis, cross coupling reactions such as Heck and Suzuki coupling reactions. Herein we report the comprehensive analysis on the role of HA in organic transformations providing diverse array of molecular scaffolds till date and future perspective.

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Section: Humic Acid In Functionalized Pyran Synthesismentioning

confidence: 99%

Humic Acid: A Promising and Green Bioorganic Catalyst in Organic Syntheses

Swaraj Acharya,

Bhusan Parida

2024

ChemistrySelect

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“…Pyrazoles and related fused heterocyclic compounds show a wide range of biological and pharmaceutical activities . Among them, pyrano[2,3- c ]pyrazoles have attracted considerable attention from synthetic chemists due to their remarkable bioactivities . Although there are several ways to access pyrano[2,3- c ]pyrazoles, the exploration of novel and simple synthetic methods remains highly desirable.…”

Section: Introductionmentioning

confidence: 99%

Copper-Catalyzed Cascade Annulation of o-Hydroxyphenyl Propargylamines with Pyrazolin-5-ones to Access Pyrano[2,3-c]pyrazoles

Jin

Wang

et al. 2022

J. Org. Chem.

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An efficient copper-catalyzed cascade annulation of o-hydroxyphenyl propargylamines and pyrazolin-5-ones is described. This methodology leads to the rapid assembly of a series of valuable pyrano[2,3-c]pyrazoles with good yields across a wide range of substrates in a simple fashion. This novel reaction involves the formation of alkynyl ortho-quinone methides, a 1,4-conjugate addition, and a subsequent 6-endo cyclization process. The mechanistic elucidation is well supported by control experiment and literature precedents.

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“…has synthesized 6,6’ ‐Thiobis(methylene)‐β‐cyclodextrin dimer and used as a catalyst in aqueous medium at 45 °C, [33] Md. M. Khan and his co‐workers have developed a solvent and catalyst free approach at 110 °C [34] . These explained routes have shown excellent outcomes in many instances.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid Promoted Regio‐Selective Synthesis of 2‐Methyl amino‐3‐Nitro‐pyrano[3,2‐c]chromen‐5‐ones

Katariya

Gaikwad

Kadam³

et al. 2022

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An efficient, and simple protocol for the synthesis of extremely functionalized pyrano[3,2‐c]chromen‐5‐ones (4 a–v) has been developed. One‐pot multicomponent cyclo‐condensation of 4‐hydroxycoumarin, aromatic‐aldehydes, and (E)‐N‐methyl‐1‐(methylthio)‐2‐nitroethenamine (NMSM) catalyzed by ionic liquid [(EMIM)Ac] in two different methods as methanolic mediated and at solvent free condition is described which presumably involve the Knoevenagel reaction succeeding Michael‐addition and O‐cyclization with elimination of methanethiol. The noteworthy features of this protocol are use of ionic liquid as catalyst, good to excellent yield, optimum reaction time with easy experimental procedure. The prepared derivatives were characterized by IR, 1HNMR,13CNMR and HRMS spectroscopic techniques.

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A catalyst- and solvent-free protocol for the sustainable synthesis of fused 4H-pyran derivatives

Abstract: A practical and greener method for the synthesis of highly functionalized pyrazole and coumarin fused 4H-pyran derivatives by exploring NMSM under neat conditions at 110 °C is described.

Cited by 16 publications

References 48 publications

Humic Acid: A Promising and Green Bioorganic Catalyst in Organic Syntheses

Humic Acid: A Promising and Green Bioorganic Catalyst in Organic Syntheses

Copper-Catalyzed Cascade Annulation of o-Hydroxyphenyl Propargylamines with Pyrazolin-5-ones to Access Pyrano[2,3-c]pyrazoles

Ionic Liquid Promoted Regio‐Selective Synthesis of 2‐Methyl amino‐3‐Nitro‐pyrano[3,2‐c]chromen‐5‐ones

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