Easy Access to Coumarin Derivatives Using Alumina Sulfuric Acid as an Efficient and Reusable Catalyst under Solvent‐Free Conditions

Amoozadeh, Ali; Ahmadzadeh, Majid; Kolvari, Eskandar

doi:10.1155/2013/767825

Cited by 23 publications

(8 citation statements)

References 32 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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“…Both conditions gave high to excellent yield (88-93%), but in microwave synthesis reaction time was shorter. Amoozadeh et al reported solvent-free Pechmann condensation for coumarin derivatives synthesis using alumina sulfuric acid (ASA) as reusable catalyst [104]. Model reaction of resorcinol and ethyl acetoacetate was performed in the presence of different alumina and alumina supported acids and the best yield was obtained in a reaction catalyzed by ASA.…”

Section: Scheme 42mentioning

confidence: 99%

Recent Advances in the Synthesis of Coumarin Derivatives from Different Starting Materials

et al. 2020

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The study of coumarin dates back to 1820 when coumarin was first extracted from tonka bean by Vogel. Compounds containing coumarin backbone are a very important group of compounds due to their usage in pharmacy and medicine. Properties and biological activities of coumarin derivatives have a significant role in the development of new drugs. Therefore, many different methods and techniques are developed in order to synthesize coumarin derivatives. Coumarin derivatives could be obtained from different starting materials with various methods but with big differences in yield. This review summarized various methods, techniques and reaction conditions for synthesis of coumarins from different compounds such as aldehydes, phenols, ketones and carboxylic acids.

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“…Silica supports have the advantages of good accessibility, excellent chemical and thermal stability, and large surface area for easy functionalization. In addition, ASA [ 44 ] has been reported as the catalyst for Pechmann condensation reactions, similar to silica-supported sulfuric acid (Entry 7).…”

Section: Synthetic Routes Toward Central 2-pyrone Of 4-arylcoumarimentioning

confidence: 99%

Recent Advances in Synthesis of 4-Arylcoumarins

et al. 2018

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4-Arylcoumarins (4-aryl-2H-1-benzopyran-2-one), also known as neoflavones, comprise a minor subclass of naturally occurring flavonoids. Because of their broad-spectrum biological activities, arylcoumarins have been attracting the attention of the organic and medicinal chemistry communities, and are considered as an important privileged scaffold. Since the development of Pechmann condensation, a classical acid-catalyzed condensation between phenol and β-keto-carboxylic acid, several versatile and efficient synthetic approaches for 4-arylcoumarins have been reported. This review summarizes recent advances in the synthesis of the 4-arylcoumarin scaffold by classifying them based on the final bond-formation type. In particular, synthetic methods executed under mild and highly efficient conditions, such as solvent-free reactions and transition metal catalysis, are highlighted.

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Easy Access to Coumarin Derivatives Using Alumina Sulfuric Acid as an Efficient and Reusable Catalyst under Solvent‐Free Conditions

Abstract: A new and efficient condition for the use of alumina sulfuric acid (ASA) as a heterogeneous catalyst in the Pechmann condensation reaction in solvent-free condition for the formation of coumarins has been reported.

Cited by 23 publications

References 32 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

Recent Advances in the Synthesis of Coumarin Derivatives from Different Starting Materials

Recent Advances in Synthesis of 4-Arylcoumarins

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