4th EucheMs chemistry congress

Poster Session 2
s1190
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - Green Chemistry
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enzyMe-CAtALySed reSoLution
of n-BoC-3-hydroxy-4-PhenyLPyrroLidine in
SuPerCritiCAL CArBon-dioxide
A. SzeCSenyi 1 , M. utCzAS 1 , d. BALoGh 2 ,
e. KovACS 2 , e. SzeKeLy 1 , f. fAiGL 2 , B. SiMAndi 1
1 Budapest University of Technology and Economics,
Department of Chemical and Environmental Process
Engineering, Budapest, Hungary
2 Budapest University of Technology and Economics,
Department of Organic Chemistry and Technology, Budapest,
Hungary
The preparation of enantiopure drug intermediates is a topic
of great importance in research. While there are numerous
chemical methods for producing pure enantiomers, using enzymes
has many advantages compared to other processes. The enzymes
most commonly used for kinetic resolution are lipases, some of
which could be active in supercritical media as well. Supercritical
carbon-dioxide (scCO ) is a solvent with industrial applications.
2
Among its many advantages is the fact that its properties (density,
viscosity) can be modified in a wide range by changing the
pressure and temperature. Due to its relatively mild critical
parameters, the decomposition of the product and substrate can
be avoided. After depressurization, carbon-dioxide becomes
gaseous, thus potentially yielding a solvent-free product.
The kinetic resolution of N-Boc-3- hydroxy-4-phenylpyrrolidine
was investigated by CALB-catalysed (lipase B from Candida
Antarctica) acylation with vinyl acetate in scCO in a batch
2
reactor. The substrate:CALB mass ratio was 2:1. Vinyl acetate
was used in excess. The samples were analyzed by chiral gas
chromatography. The reaction progress was examined at different
pressures (10–20 MPa) and temperatures (35–65°C) according to
a 32 experimental design.
In this reaction at 15 MPa and 50 °C, enantiopure
(3R,4S)-N-Boc-3-hydroxy-4-phenylpyrrolidine (ee≥99.9 %) was
achieved with good yield (Y~60 %) and moderate
enantioselectivity (E~50). Increasing the temperature increases
both the enzyme activity and the enantioselectivity, while
enantioselectivity has an optimal pressure range around 15 MPa.
Increasing the pressure has a negative effect on the reaction rate
in the examined range.
Acknowledgement: Our research was supported by the
Hungarian Scientific Research Fund (OTKA 72861) and
TAMOP-4.2.1/B-09/1/KMR-2010-0002.
Keywords: kinetic resolution; supercritical fluids; enzyme
catalysis;
4 th EucheMs chemistry congress
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MetAheSiS reACtionS PerforMed in Pure
wAter, uSinG CoMMerCiAL CAtALyStS
J. toMASeK 1 , M. SeSSLer 1 ,
P. of. dr. JuerGen SChAtz 1
1 Friedrich-Alexander-University Erlangen-Nuremberg, Chemie
und Pharmazie, Erlangen, Germany
Olefin metathesis is an interesting, atom-efficient, and very
valuable synthetic transformation, mainly performed in organic
solvent. Subsequently, fewer studies on metathesis reactions in
pure water as solvent were done.
We showed that olefin metathesis can be performed very
efficiently in pure water without exclusion of air, using standard
Grubbs-type catalyst. Beside activity, also stability tests were
determined by standard RCM reactions.
Addition of host molecules such as calix[n]arenes can boost
the reactivity by a supramolecular interaction with in water
protonated Cy3P which is released in the activation step of the
catalysts.
Keywords: Metathesis; water chemistry; supramolecular
chemistry; ion pair;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc