Affiliations 

  • 1 Chemistry Department, College of Science, Taibah University, P.O. Box 30002, Al-Madinah Al-Munawarah 14177, Saudi Arabia. musa_said04@yahoo.co.uk
  • 2 Institut für Chemie und Biochemie, Anorganische Chemie, Freie Universität Berlin, Fabeckstr. 34-36, 14195 Berlin, Germany. dlentz@zedat.fu-berlin.de
  • 3 Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia. norazahb@utm.my
  • 4 Department of Physics, College of Science, Jeddah University, P.O. BOX 80327, Jeddah 21589, Saudi Arabia. arwa.albar@kaust.edu.sa
  • 5 Chemistry Department, College of Science, Taibah University, P.O. Box 30002, Al-Madinah Al-Munawarah 14177, Saudi Arabia. shaya97@hotmail.com
  • 6 Chemistry Department, College of Science, Taibah University, P.O. Box 30002, Al-Madinah Al-Munawarah 14177, Saudi Arabia. AdeebAli@Dal.Ca
Molecules, 2019 Feb 07;24(3).
PMID: 30736403 DOI: 10.3390/molecules24030590

Abstract

An efficient microwave-assisted one-step synthetic route toward Mannich bases is developed from 4-hydroxyacetophenone and different secondary amines in quantitative yields, via a regioselective substitution reaction. The reaction takes a short time and is non-catalyzed and reproducible on a gram scale. The environmentally benign methodology provides a novel alternative, to the conventional methodologies, for the synthesis of mono- and disubstituted Mannich bases of 4-hydroxyacetophenone. All compounds were well-characterized by FT-IR, ¹H NMR, 13C NMR, and mass spectrometry. The structures of 1-{4-hydroxy-3-[(morpholin-4-yl)methyl]phenyl}ethan-1-one (2a) and 1-{4-hydroxy-3-[(pyrrolidin-1-yl)methyl]phenyl}ethan-1-one (3a) were determined by single crystal X-ray crystallography. Compound 2a and 3a crystallize in monoclinic, P2₁/n, and orthorhombic, Pbca, respectively. The most characteristic features of the molecular structure of 2a is that the morpholine fragment adopts a chair conformation with strong intramolecular hydrogen bonding. Compound 3a exhibits intermolecular hydrogen bonding, too. Furthermore, the computed Hirshfeld surface analysis confirms H-bonds and π⁻π stack interactions obtained by XRD packing analyses.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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