Zaharani, Lia and Ghafarikhaligh, Mahta and Titinchi, Salam and Johan, Mohd Rafie and Khaligh, Nader Ghaffari (2023) Simultaneous activation of aldehydes and methylamine liberation by 4,4′-trimethylenedipiperidine in the solid-state synthesis of N-methyl imines. Research on Chemical Intermediates, 49 (8). pp. 3519-3538. ISSN 0922-6168, DOI https://doi.org/10.1007/s11164-023-05045-z.
Full text not available from this repository.Abstract
The commercially available 4,4'-trimethylenedipiperidine (TMDP) was used in the solid state to activate various aldehydes and controlled the libration of methyl amine for preparing the corresponding N-methyl imines. It was indicated that TMDP could play multiple roles simultaneously in this reaction, including (a) a bifunctional base with a predicted pK(a) similar to 11 and a good scavenger of acid, (b) a catalyst able to form strong hydrogen bonding and chemical interactions with aldehyde functional group through hemiaminal and/or iminium intermediate, and (c) liberating methyl amine from its salt viz. methylammonium chloride. TMDP could be regenerated by neutralization. It was also regenerated by heating at 70 degrees C, which is reported for the first time according to the best of our knowledge. The regenerated reagent was stable regarding its chemical structure, and there was no significant loss in the catalytic efficiency even after several runs. The mechanism was investigated by performing several control reactions and studying the FTIR and NMR spectra in the solid-state synthesis. The current work demonstrated TMDP as a safe and greener promoter-acid scavenger for organic transformations compared with toxic, flammable, volatile liquid secondary amines such as piperidine.
| Item Type: | Article |
|---|---|
| Funders: | Research Grant IF008-2023 from Nippon Sheet Glass Foundation for Materials Science and Engineering, Japan, ST018-2022 from UM International Collaboration Grant, Universiti Malaya, Malaysia |
| Uncontrolled Keywords: | Organocatalysis; Solid-state synthesis; Hydrogen bond; Schiff bases; Reaction mechanism |
| Subjects: | Q Science > Q Science (General) Q Science > QD Chemistry |
| Divisions: | Deputy Vice Chancellor (Research & Innovation) Office > Nanotechnology & Catalysis Research Centre |
| Depositing User: | Ms. Juhaida Abd Rahim |
| Date Deposited: | 06 Oct 2025 02:39 |
| Last Modified: | 06 Oct 2025 02:39 |
| URI: | http://eprints.um.edu.my/id/eprint/50275 |
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