SYMPOSIUM
ON UNDERGRADUATE RESEARCH EXPERIENCES
Jeffrey Rockwell1 and Jim Peploski2
Department of Chemistry
A
system for introducing the principles of QSAR to undergraduates, which
relies on the simultaneous analysis of many biologically active molecules,
has been implemented in Freshman Chem. laboratory. Computational modeling
of molecular structures and calculation of physical properties allows
for the genereation of sufficient information to define statistically
relevant relationships between physical properties and biological activities.
Application of this approach to a series of 12 Phenylalkylamine hallucinogens
with geometries optimized using semi-empirical AM1 methodology results
in a strong nonlinear correlation between activity and the calculated
octonal/water partition coefficient (Log P). The correlation equation
[Log (Activity) = -.863799 Log P2 +5.14208 Log P -5.74332 (R=0.789)]
compared very favorably with that for experimentally determined LogP values
[ Log(Activite)=-.5Log P2+3.15Log P -3.17 R=.79 ]. A comparison
of molecular electrostatic potential (EP) calculated at the same level
of theory to Hammett constants (F) for a series of substituted benzoic
acids yields a similarly strong relationship were [F = 7.8511EP + 31.592
R= 0.812]. EP, which can be easily calculated, can therefore be used as
an acceptable replacement for Hammet constant values in the evaluation
of QSAR relationships where electronic substituant effects are important.
- Class of 2001, Oral Presentation
- Assistant Professor, Clarkson University
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