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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. November 2004, Volume 3, Number 11, 737-749 |
13C NMR Pattern Recognition of Guaiane Sesquiterpenes
Marcelo J. P. Ferreira, Francimeiry C. Oliveira, Gilberto V. Rodrigues, and Vicente P. Emerenciano
Internet Electron. J. Mol. Des. 2004, 3, 737-749
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Abstract:
Sesquiterpenes are a class of naturally occurring substances that
show various biological and pharmacological properties such as
inhibitors of cell growth, antifungal, antibacterial, antimalarial,
antiviral, etc activities. However, jointly with many biological
properties, this class exhibits a greater diversity and complexity
of structures, becoming a great challenge in the structural
elucidation of its compounds for spectroscopists. Thus, the
development of an expert system containing a set of rules for
structural pattern recognition, based on 13C NMR spectral data,
for new compounds is of utmost importance for the natural
product researchers. SISTEMAT is an expert system developed
to aid in the structural determination of natural products. In this
study we have investigated the application of system for the 13C
NMR pattern recognition of guaiane sesquiterpenes. By using a
database containing 200 substances, and the programs of the
system SISTEMAT, various 13C NMR heuristic rules for
structural elucidation were obtained. These rules were evaluated
with a set of 25 new guaianes recently published in literature.
The prediction performance of the system from the tests executed
with the compounds shows that the system was able to propose
substructures in 96.0% of the studied cases, where in 98.1% of
these are overlapping substructures. SISTEMAT is a powerful
tool for structural elucidation with many potential applications in
natural products' field. In the present study we have
demonstrated the predictive ability and applicability of a 13C
NMR pattern recognition method for the guaiane sesquiterpenes.
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