4,4 `-trimethylenedipiperidine as a nitrogen heterocycle solvent and/or catalyst: Liquid phase tandem Knoevenagel-Michael condensation

Zaharani, Lia and Khaligh, Nader Ghaffari and Gorjian, Hayede and Johan, Mohd Rafie (2021) 4,4 `-trimethylenedipiperidine as a nitrogen heterocycle solvent and/or catalyst: Liquid phase tandem Knoevenagel-Michael condensation. Turkish Journal of Chemistry, 45 (1). 261+. ISSN 1300-0527, DOI https://doi.org/10.3906/kim-2010-41.

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Liquid phase tandem Knoevenagel-Michael condensation of various aromatic and heteroaromatic aldehydes with barbituric acid or 2-thiobarbituric acid and malononitrile was studied in a one-pot three-component reaction. For the first time, TMDP was employed as a safe and efficient solvent and/or catalyst in the liquid and aqueous ethanol medium, respectively, for the practical and eco-friendly Knoevenagel-Michael condensation. The reactions were carried out by using greener procedures, including a) the use of TMDP as an N-heterocycle organocatalyst in a green medium including water and ethanol (1:1 v/v) at reflux temperature, and b) the use of TMDP as a dual solvent-catalyst at 65 degrees C in the absence of any solvent. High to excellent yields of the desired pyrano2,3-d] pyrimidinones were obtained under the two earlier mentioned conditions. The current methodologies have advantages, including (a) avoiding hazardous, toxic, volatile, and flammable materials and solvents, (b) avoiding tedious processes, harsh conditions, and multiple steps for the preparation of catalysts, (c) using a less toxic and noncorrosive catalyst, (d) minimizing hazardous waste generation and simple workup process, and (e) high recyclability of TMDP. Another important result of this work is that the TMDP can be a promising alternative for toxic, volatile, and flammable base reagents such as piperidine and triethylamine in liquid phase organic syntheses owing to its unique properties such as being less toxic, nonflammable, and nonvolatile, and having a low melting point, broad liquid range temperature, high thermal stability, and safe handling and storage.

Item Type: Article
Funders: Universiti Malaya[NANOCAT RU001-2020]
Uncontrolled Keywords: Homogeneous catalysis; Heterocycles; Multicomponent reactions; Waste prevention
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
T Technology > TP Chemical technology
Divisions: Nanotechnology & Catalysis Research Centre
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 14 Apr 2022 05:55
Last Modified: 14 Apr 2022 05:55
URI: http://eprints.um.edu.my/id/eprint/26793

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