Highly Efficient Reusable Carboxy Group Functionalized Imidazolium Salts for a Simple and Cost-effective Preparation of pyrano[2,3-d]pyrimidinone Derivatives

Title:Highly Efficient Reusable Carboxy Group Functionalized Imidazolium Salts for a Simple and Cost-effective Preparation of pyrano[2,3-d]pyrimidinone Derivatives

Volume: 24 Issue: 9

Author(s): Elham Ezzatzadeh*, Fatemeh Sheikholeslami-Farahani, Khadijeh Yadollahzadeh and Sobhan Rezayati

Affiliation:

• Department of Chemistry, Ardabil Branch, Islamic Azad University, Ardabil,Iran

Keywords: Imidazolium salts, Ionic liquids (ILs), Pyrano[2, 3-d]pyrimidinones, Brønsted acid catalyst, Aldehyde

Abstract:

Aims and Objective: In the current study, environmentally benign and cost-effective procedures were suggested for the preparation of carboxy group functionalized imidazolium salts, including [Cmmim]BF₄ - or [Cmmim]Br- as a new, reusable Brønsted acidic ionic liquid (BAIL) catalyst. Then, the catalytic performance of [Cmmim]BF₄ - or [Cmmim]Br- were successfully inspected towards the three-components onepot preparation of pyrano[2,3-d]pyrimidinone derivatives 4a-4q. The mentioned procedures show short reaction times, easy work-up procedure, green conditions, high yields of the products, high potent of recovering, and reusing capability. The current study is useful and adequate for the application and development of imidazolium salts on the basis of green chemistry principles.

Materials and Methods: An aromatic aldehyde (1 mmol), barbituric acid (1 mmol), and malononitrile (1 mmol) were placed in a round-bottomed flask containing ethanol (5 mL). BAILs A and B (0.1 mmol, 10 mol%) were added to the mixture. The suspension was magnetically stirred at room temperature for an appropriate time (Table 2). After completion of the reaction, which was monitored by TLC (n-hexane:ethyl acetate = 3:1), the pure product was filtered off to separate the catalyst, washed with water, and recrystallized from ethanol to afford the pure compound. After separation of the product, the catalyst was recovered by evaporation of water, washed with Et₂O, dried under vacuum for 2 h, and reused for the same reaction.

Results: The mentioned procedure shows short reaction times, easy work-up procedure, green conditions, high yields of the products, and high potent of recovering and reusing capability.

Conclusion: In this study, we unveiled the synthesis of a new acetic acid functionalized ionic liquids [Cmmim]BF₄ - BAIL A or [Cmmim]Br- BAIL B and their application for the preparation of pyrano[2,3-d]pyrimidinone derivatives via a three-component reaction among various aromatic aldehydes, barbituric acid, and malononitrile under mild and metal-free conditions. A wide range of pyrano[2,3-d]pyrimidinone derivatives bearing diverse functional groups was obtained in short reaction and excellent yields. Operational simplicity, recoverability, and reusability of catalysts, cheap and chemically stable reagents, high catalytic activity, easy work-up, and the eco-friendly procedure, make this method environmentally benign and cost-effective.

Cite this article as:

Ezzatzadeh Elham *, Sheikholeslami-Farahani Fatemeh, Yadollahzadeh Khadijeh and Rezayati Sobhan, Highly Efficient Reusable Carboxy Group Functionalized Imidazolium Salts for a Simple and Cost-effective Preparation of pyrano[2,3-d]pyrimidinone Derivatives, Combinatorial Chemistry & High Throughput Screening 2021; 24 (9) . https://dx.doi.org/10.2174/1386207323666201007154343

DOI https://dx.doi.org/10.2174/1386207323666201007154343	Print ISSN 1386-2073
Publisher Name Bentham Science Publisher	Online ISSN 1875-5402