Book of Abstracts - Ruhr-Universität Bochum

OP-15
ISBOMC `10 5.7 – 9.7. 2010 Ruhr-Universität Bochum
Arjunolic acid: The First Renewable-Nano Triterpenoid in Bioorganometallics
Braja G. Bag, *a Partha P. Dey, a Rakhi Majumdar, a Shaishab K. Dinda, a and Shib S. Das a
a Vidyasagar University, Department of Chemistry and Chemical Technolgy, Midnapore 721 102,
India. E-mail: bgopalbag@yahoo.co.in
Utilization of plant metabolites as renewables in various facets of bioorganic, bioorganometallic and
organic chemistry research has become significant in recent years because such investigations aim at
the development of sustainable chemical feedstocks. 1 Ferrocene moiety has been utilized in the design
of peptide analogues, redox-responsive gelators, enhanced antimalarial drugs, etc. 2 However, inspite
of the abundance of a large variety of triterpenoids, having nano-metric dimensions with varied
lengths of rigid and flexible parts, 3 according to our knowledge, no ferroceno-triterpenoid has been
reorted so far. Availability of arjunolic acid 1, extractable from the heavy wood of Terminalia Arjuna
became the first choice for such investigations. 4
Figure 1: (a) A redox-responsive organogel from ferrocenylidene arjunolic acid 2, (b) SEM image
reveals self-assembled fibrillar network having fibers of nano-meter diameters, (c) TEM image of CdS
nano-particles templated by self-assembled nano-fibers from arjunolic acid derivatives.
The ferrocenylidene arjunolic acid 2, synthesized in one-step from arjunolic acid 1 and formylferrocene
in high yield, self-assembled in various organic media to form soft solid-like materials
(Figure 1a, Table 1). Scanning electron micrographs of the soft-solids showed fibrillar net-work
structures having fibers of nano-metric dimensions (Figure 1b).
Solvent State Conc.
(g/100 mL)
Toluene Gel 10
o-Xylene Gel 9
m-Xylene Gel 10
p-Xylene Gel 10
Table 1: Gelation Test Results of 2
Detailed investigations on the self-assembly of arjunolic acid
or its derivatives revealed that most of these derivatives selfassemble
in aqueous or organic liquids leading to the
formation of fibers of nano-metric diameters. 5,6 When H2S
gas was diffused through a gel of an arjunolic acid derivative
in ethanol saturated with Cd(OAc)2, then porous CdS
nanoparticles templated by the self-assembled nano-fibers were formed (Figure 1c). Recent results
from our laboratory will be presented describing various approaches towards bioorganometallic
chemistry for the utilization triterpenoids.
Acknowledgements: Financial assistance from AvH foundation Germany and DRDO India are
gratefully acknowledged.
References
1. B.G. Bag, S.K. Dinda, Pure Appl. Chem. 2007, 79, 2031.
2. (a) D.R. van Staveren , N. Metzler-Nolte, Chem. Rev. 2004, 104, 5931; (b) F. Dubar, G. Anquetin,
B. Pradines, D. Dive, J. Khalife, C. Biot, J. Med. Chem. 2009, 52, 7954.
3. B.G. Bag, C. Garai, R. Majumdar, unpublished results.
4. B.G. Bag, P.P. Dey, S.K. Dinda, W.S. Sheldrick, I.M. Oppel, Beil. J. Org. Chem. 2008, 4, 24.
5. B.G. Bag, S.K. Dinda, P.P. Dey, A.V. Mallia, R.G. Weiss, Langmuir 2009, 25, 8663.
6. B.G. Bag, G.C. Maity, S.K. Dinda, Org. Lett. 2006, 8, 5457.
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