Efficient and facile synthesis of heterocycles and their mechanistic consideration using kaolin

Sahu, Pramod K.; Sahu, Praveen Kumar; Agarwal, D. D.

doi:10.1039/c3ra40993g

Cited by 26 publications

(7 citation statements)

References 79 publications

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“…The plausible mechanistic path way is shown in Scheme . It is believable that initially, catalyst graphite oxide increases the electrophilicity of carbonyl groups of aldehydes 1{1–15} , − which is attacked by β-dicarbonyl compounds 2{1–3} (in enolic form) to form Knoevenagel adduct B via dehydration of intermediate A . To prove this assumptions, we tested the pilot reaction with acidic and basic graphite oxide (acidic and basic graphite oxide have been synthesized according to the procedure reported by Zhang et al).…”

Section: Resultsmentioning

confidence: 99%

Metal-Free Greener Syntheses of Pyrimidine Derivatives Using a Highly Efficient and Reusable Graphite Oxide Carbocatalyst under Solvent-Free Reaction Conditions

Dam

Jamatia

Gupta

et al. 2017

ACS Sustainable Chem. Eng.

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Graphite oxide, a green metal-free carbocatalyst, has been successfully exploited for the library synthesis of biologically active pyrimidine derivatives. Reaction was carried out under solvent-free reaction conditions (SFRC) thereby reducing the application of hazardous chemicals and solvents. The present catalytic system eliminates the risk of metal contamination in the product which is viable for pharmaceutical industries and showed better catalytic activity under sustainable conditions compared to other classical catalytic systems. The catalyst, being heterogeneous in nature, can be easily recycled and reused up to nine consecutive runs without much decrease in catalytic activities thereby increasing sustainability of the procedure. Diversity in the formation of pyrimidine moieties has been exhibited with the tolerance of a large number of functional groups establishing the generality of this reaction. A few other cutting edge advantages of the present one-pot multicomponent methodology are high atom economy, low catalyst loading, milder reaction conditions, higher yield of the desired product, simple work up procedure, easy handling of the catalyst, etc. The present methodology showed good results in gram scale conditions thereby indicating its applicability in academic as well as industrial settings in the near future.

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Section: Resultsmentioning

confidence: 99%

Metal-Free Greener Syntheses of Pyrimidine Derivatives Using a Highly Efficient and Reusable Graphite Oxide Carbocatalyst under Solvent-Free Reaction Conditions

Dam

Jamatia

Gupta

et al. 2017

ACS Sustainable Chem. Eng.

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“…Coupling between alkynoic acid and 2-aminobenzothiazole and the use of ionic liquids have also been developed [ 88 ]. Heterogeneous catalysts such as kaolin and hydrotalcites have been employed in the synthesis of benzo[4,5]thiazolo[3,2- a ]pyrimidin-4-ones [ 89 – 90 ]. Polyphosphoric acid has also been used to access 5a by coupling 2-aminobenzothiazole with β-ketoesters [ 79 , 91 – 92 ].…”

Section: Resultsmentioning

confidence: 99%

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

Roslan¹,

Ng²,

Chuah³

et al. 2017

Beilstein J. Org. Chem.

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Two regiodivergent approaches to intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and amides have been developed, controlled by the reagents employed. With the Brønsted base KOt-Bu and CBrCl3 as radical initiator, benzo[d]imidazo[2,1-b]thiazoles are synthesized via attack at the α-carbon and keto carbon of the β-ketoester moiety. In contrast, switching to the Lewis acid catalyst, In(OTf)3, results in the regioselective nucleophilic attack at both carbonyl groups forming benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones instead.

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“…The product was recrystallized from an acetone/water mixture. Spectroscopic data of products were in agreement with those previously reported. ,− …”

Section: Methodsmentioning

confidence: 99%

“Solvent-Less” Mechanochemical Approach to the Synthesis of Pyrimidine Derivatives

Raj

Sharma

Mayank

et al. 2017

ACS Sustainable Chem. Eng.

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Modified ZnO NPs were synthesized through a sol–gel route with an aromatic capping agent to provide a highly efficient catalyst, NS-5, for the one-pot multicomponent synthesis of various pyrimidine derivatives using a solvent-free ball milling technique. Greenness of the present method was evaluated by calculating an Ecoscale score and E-factor. Characteristics of the method include use of a recyclable catalyst, scale-up to a multigram scale, and ease of product isolation.

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Efficient and facile synthesis of heterocycles and their mechanistic consideration using kaolin

Cited by 26 publications

References 79 publications

Metal-Free Greener Syntheses of Pyrimidine Derivatives Using a Highly Efficient and Reusable Graphite Oxide Carbocatalyst under Solvent-Free Reaction Conditions

Metal-Free Greener Syntheses of Pyrimidine Derivatives Using a Highly Efficient and Reusable Graphite Oxide Carbocatalyst under Solvent-Free Reaction Conditions

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

“Solvent-Less” Mechanochemical Approach to the Synthesis of Pyrimidine Derivatives

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