Novel Polymer Supported Reagents for Organic Synthesis
Yoon-Sik Lee, Jang-Woong Byun, Woo-Jae Chung, Jong-Ho Kim
School of chemical engineering, Seoul National University
Seoul 151-744, Republic of Korea
(e-mail : yslee@snu.ac.kr)
Polymer supported reagents and catalysts have gained enormous interests in
organic chemistry due to many advantages such as easy work up, simple product
isolation and recycling. Very recently, we have developed polymer supported IBX
reagents1 and palladium catalysts.2,3 In the first part, we present a novel polymer
supported IBX reagents and their oxidative properties. The polymer supported
reagents were readily prepared in two steps, involving the coupling of 2-iodobenzoic
acid to a hydroxy or amino functionalized polystyrene (PS) bead, followed by
subsequent oxidation on the beads. We proved that the polymer supported IBX
reagents were mild and efficient oxidants in the conversion of series of alcohols to
the corresponding aldehydes or ketones. In the second part, we present two types of
polymer supported palladium catalysts and their activities in the Suzuki cross
coupling reactions. Homogeneous catalysis using NHCs (N-Heterocyclic carbenes)
as a ligand for transition metals, particularly palladium,4 have been reported recently.
However, several problems with these homogeneous catalysis systems have always
been existed; separation and recycling of the catalysts and contamination of the
ligand residue in the final product. In order to avoid these problems, several types of
heterogeneous catalysts have been developed by anchoring the Pd-adppp onto a
PS-PEG5a, and a Pd-NHCs complex onto a Wang resin5b and PS-DVB5c. These
trends of heterogeneous catalysis inspired us to design two novel polymer-supported
ligands that can form effective complexes with palladium.
1. Chung, W.J.; Kim, D.K.; Lee, Y.S. Tetrahedron Lett. 2003, 44, 9251
2. Byun, J.W.; Lee, Y.S. Tetrahedron Lett. 2004, 45, 1837
3. Kim, J.H.; Jun, B.H.; Byun, J.W.; Lee, Y.S. Tetrahedron Lett. 2004, accepted
4. (a) Gabriela A, Grasa.; Mihai S, Viciu.; Jinkun Huang.; Chunming Zhang.; Mark L, Trudell.;
Steven P, Nolan. Organometallics. 2002, 21, 2866 (b) Merritt B, Andrus.; Chun Song. Org. Lett.
2001, 3, 3761 (c) Lijin Xu.; Weiping Chen.; Jianliang Xiao. Organometallics. 2000, 19, 1123
5. (a)Yasuhiro Uozumi.; Yasushi Nakai. Org. Lett. 2002, 4, 2997 (b) Schwarz, J.; Böhm, V.P.W.;
Gardiner, M.G.; Grosche, M.; Herrmann, W.A.; Hieringer, W.; Raudaschl-Sieber, G. Chem.
Eur. J., 2000, 6, 1773 (c) Monika Mayr.; Michael R. Buchmeiser. Macromol. Rapid Commun.
2004, 25, 231 (d) Byun, J.W.; Lee, Y.S. Tetrahedron Lett. 2004, 45, 1837
Microsystems for Peptide Synthesis and Protein Research
Yoon-Sik Lee1, Do-Hyun Kim1, Dong-Sik Shin1, Kook-Nyung Lee2,
and Yong-Kweon Kim2,
1
School of Chemical Engineering, Seoul National University
2
School of Electrical Engineering & Computer Science, Seoul National University
(e-mail : yslee@snu.ac.kr)
As we enter the post-genome era, the demand for developing a rapid and eff
ective method for the peptide array synthesis and protein identification is increasi
ng. We have developed two methods for peptide synthesis on a glass chip surface,
spotting method1 and maskless photolithography method2. For a more effective
peptide synthesis and protein patterning on a chip, we modified the glass surfaces in
various ways and proved that such modification with a hydrophilic polymer is more
suitable for peptide synthesis and bioassays. The modified surfaces were
characterized by contact angle measurement, atomic force microscopy (AFM), X-ray
photoelectron spectroscopy (XPS), and confocal fluorescence microscopy. We
performed protein adsorption test on the modified glass surfaces via enzymesubstrate reaction and fluorescence intensity measurement.
For the spot synthesis, we developed a simple method to make spot arrays on a
glass surface (1.8 mm2 × 40 spots) by patterning the glass surface with photo-resist
and perfluorination. We introduced amino functional groups on the surface of spots
and measured coupling time of each amino acid on the glass surface. By doing this,
we can identify the optimal surface condition for step-wise peptide couplings and
bioassays. Peptide and protein micro array (50x50 m2) chips have also been devel
oped using photolithography method by using micromirror array (MMA) system. As a
model case, we synthesized HPQ containing pentapeptides on a glass chip using
nitroveratryloxycarbonyl (NVOC) amino acids. The NVOC-protecting groups on glass
surface were site-specifically removed by irradiating with a UV illuminator (360 nm)
using MMA. After incubating the peptide array chip with FITC-streptavidin, we could
obtain different intensities of fluorescence images, which correspond to the binding
activities of the peptides to the protein on a chip. We were successful in proving that
the micro systems are effective for peptide array synthesis and binding assay, and
have been found to be much simpler than the conventional SPPS.
1. Frank, R. J. Immunol. Methods, 2002, 267, 13
2.
Lee, K. N.; Shin, D. S.; Lee, Y. S.; Kim, Y. K. J. Micromech. Microeng. 2003, 13, 18