Synthesis and Characterization of a Butenafine Analogue | Chapter 07 | Theory and Applications of Chemistry Vol. 3
Aims:
The study aims: (I) To synthesise N-(4-(tert-butyl) benzyl)-1-(4-tert-butyl)
phenyl)-N-methyl methanaminium chloride, an
analogue of butenafine from
tertiary-butyl benzyl derivatives, (II) to compare the solvent actions of
Tetrahydrofuran (THF), acetonitrile, methanol and 1,2-dichloroethane (DCE), and
the reducing efficiencies of NaBH4 and sodium triacetoxyborohydride
(STAB) during the synthesis.
Study Design: The study involved
laboratory experiments leading to the synthesis of the target compound by
varying the non-aqueous solvents used, the reducing agent and the temperature
of the operations. Silica chloride catalyst was used to speed up the reaction
in one of the syntheses and in each synthesis, Thin Layer Chromatography was
used to monitor the progress of the reaction. The time taken by each reaction
and the yield were used as the basis for determining the solvent action and the
reducing efficiency.
Place and Duration of Study: M.Sc.
Access controlled Teaching Laboratory, School of Chemistry, Newcastle
University, New castle upon Tyne, United Kingdom from June to August 2012.
Methodology: Reductive amination was
carried out by reacting 4-tert-butylbenzaldehyde and 4-tert-butylbenzylamine,
using the direct and then the indirect approaches. This was followed by
methylation using the Eschweiler-Clarke reaction in each of the two approaches.
The time taken by each reaction was monitored and the product of each approach
was characterised by EIS-MS, 1H NMR, 13C NMR and FTIR.
Results: 1,2-dichloroethane gave the
best solvent action at 40°C (Yield: 75%) and NaBH4 gave the best-reducing action with silica
chloride catalyst at 25°C (Yield: 50%). At the end of each synthesis, in all obtained products, 1H NMR spectrum gave a
single peak of 18 hydrogen atoms at 1.3 -1.5 ppm for the existence of 6 methyl
groups in the two tertiary-butyl substituents, the 13C NMR spectrum
also showed a peak at 31-32 ppm for the
six methyl carbon atoms in the two tertiary-butyl substituents, the FTIR
spectrum showed a strong band at 2460 cm-1 for the presence of a
tertiary ammonium ion and finally the EIS-MS gave a mass to charge ratio of 324.2693 as a
confirmation of the relative molecular mass of the compound.
Conclusion: The target compound can be synthesised by
both direct and the indirect approaches of reductive amination in any of the
solvents tested with/without a catalyst at room or elevated temperature using
NaBH4 or STAB as a reducing agent but the best solvent action can be
achieved with DCE at 40°C and the best-reducing action can be achieved with
NaBH4 in the presence of silica chloride.
Author(s) Details
M. A. Muhammad
Department of Chemistry,
Ibrahim Badamasi Babangida University, P.M.B 11, Lapai, Niger State, Nigeria.
A. M. Jimoh
Department of Chemistry,
Ibrahim Badamasi Babangida University, P.M.B 11, Lapai, Niger State, Nigeria.
A. Awwal
Department of Chemistry,
Ibrahim Badamasi Babangida University, P.M.B 11, Lapai, Niger State, Nigeria.
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