A solvent-free synthesis of coumarins via Pechmann condensation using heterogeneous catalyst

Maheswara, Muchchintala; Siddaiah, Vidavalur; Damu, Guri L.V.; Rao, Yerra Koteswara; Rao, C. Venkata

doi:10.1016/j.molcata.2006.03.051

Cited by 100 publications

(57 citation statements)

References 22 publications

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“…The synthesis of coumarin molecules has been established using different approaches such as Pechmann condensation [22][23][24][25], Perkin reaction [26][27][28], Witting reaction [29][30][31], Claisen rearrangement [32], Reformatsky reaction [33], Knoevenagel condensation [34][35][36][37], and flash vacuum pyrolysis [38]. Among the mentioned methods, the Pechmann reaction remains one of the most successful techniques to synthesize coumarin compounds.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

et al. 2018

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New modified acidic catalysts were prepared from the treatment of silica, titania and silica prepared from hydrolyzed tetraethyl orthosilicate (TEOS) with sulfuric and phosphoric acid. The sulfated and phosphated silica synthesized from TEOS were calcined at 450 and 650 • C. These catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), and scanning electron microscope (SEM). The surface areas, total pore volume, and mean pore radius of the acidic catalysts were investigated, while the pore size distribution was determined by the Barrett, Joyner and Halenda (BJH) method. The catalytic activity of the sulfated and phosphated silica and/or titania were examined with the Pechmann condensation reaction, in which different phenols reacted with ethyl acetoacetate as a neat reaction to obtain the corresponding coumarin derivatives. The results indicated that the treatment of the catalysts with sulfuric or phosphoric acid led to a decrease in the phases' crystallinity to a certain degree. The morphology and the structure of the acidified catalysts were examined and their particle size was calculated. Furthermore, the amount of the used catalysts played a vital role in controlling the formation of the products as well as their performance was manipulated by the number and nature of the active acidic sites on their surfaces. The obtained results suggested that the highest catalytic conversion of the reaction was attained at 20 wt % of the catalyst and no further increase in the product yield was detected when the amount of catalyst exceeded this value. Meanwhile the phenol molecules were a key feature in obtaining the final product.

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Section: Introductionmentioning

confidence: 99%

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

et al. 2018

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“…The combination of coumarins with some nitrogen heterocycles such as pyrrole and thiazole can effectively increase the bioactivity and broaden antimicrobial spectrum [223][224][225][226]. Recently, the introduction of triazole ring into coumarins has also been reported to display excellent bioactivity.…”

Section: N-alkylation With Halidesmentioning

confidence: 99%

Current Developments in the Syntheses of 1,2,4-Triazole Compounds

Zhang¹,

Damu²,

Cai³

et al. 2014

COC

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Heterocyclic 1,2,4-triazole derivatives possess unusually spacious potentiality as medicinal agents, agricultural chemicals, functional materials, ionic liquids, supramolecular catalysts as well as artificial enzymes and receptors for supramolecular recognition and biomimetic catalysis, and their various researches and developments have been being a quite rapidly developing and active highlight topic with an infinite space. Numerous efforts have been directed toward various types of possible applications of 1,2,4-triazole-based compounds and a lot of important progress has been made, especially their preparations have attracted increasing attention. This review systematically summarized the recent advances in the syntheses of 1,2,4-triazole derivatives, including: (1) Cyclizations to form triazole ring; (2) Transformations of heterocyclic compounds to construct triazole ring; (3) Substitutions on 1,2,4-triazole ring; (4) Structural modifications in side chains of 1,2,4-triazole ring. It was hoped that this review would be helpful for the design and development of highly efficient preparation of 1,2,4-triazole derivatives with various sorts and varieties of extensively potential applications in medicine, agriculture, chemistry, materials, supramolecular sciences and so on.

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“…Some of the synthetic methods are use of microwave irradiation technique [25,26], refluxing at high temperature [27][28][29][30][31], use of ionic liquid [32], use of catalysts like SiO 2 /HClO 4 [33], SiO 2 /NaHSO 4 [34], I [35], bakers' yeast [36], metal triflates [37], tetrabutylammonium hydrogen sulfate [38], organocatalysts [39], PTSA [40], iron trifluoroacetate [41], TMSCl [42] and Ni nanoparticles [43].…”

Section: Introductionmentioning

confidence: 99%

Microwave Assisted Fast Synthesis of CuO Nanoflakes: Catalytic Application in the Synthesis of 1,4-Dihydropyridine

Bajaj¹,

Tekade²,

Lakhotiya³

et al. 2017

Acta Phys. Pol. A

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CuO nanoflakes were successfully synthesized by microwave irradiation, using copper(II) sulphate and sodium hydroxide (NaOH) as the starting materials and ethanol as the solvent. The CuO nanoflakes were characterized by using techniques such as X-ray powder diffraction, field emission scanning electron microscopy, and UV-visible absorption spectroscopy, Fourier transform infra-red spectroscopy. The synthesized CuO nanoflakes were found to have morphology like nanoflakes with narrow size distribution and high purity. Moreover, the synthesized CuO nanoflakes were used as an efficient catalyst for synthesis of a series of dihydropyridine derivatives. Optimization studies with different catalysts and solvents reveal that CuO nanoparticle in the water/ethanol mixture is efficient catalyst/solvent system for the synthesis of dihydropyridine derivative.

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A solvent-free synthesis of coumarins via Pechmann condensation using heterogeneous catalyst

Cited by 100 publications

References 22 publications

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

Current Developments in the Syntheses of 1,2,4-Triazole Compounds

Microwave Assisted Fast Synthesis of CuO Nanoflakes: Catalytic Application in the Synthesis of 1,4-Dihydropyridine

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