4th EucheMs chemistry congress

Poster Session 1
s1005
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - organic chemistry
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“MetAL-free” SyntheSiS of funCtionALized
PoLyLACtide By CAtioniC ACtivAted
MonoMer PoLyMerizAtion
M. BASKo 1 , M. BednAreK 1 , P. KuBiSA 1
1 Centre Polish Academy of Sci, Department of Polymer
Chemistry, Lodz, Poland
Poly(lactide) (PLA) is the major bio-based polymer which
can be produced from renewable resources. Due to biodegrability
and biocompatibility PLA is the candidate of choice for polymeric
commodities as well as for application in the medical field. [1]
However a lack of functional group along the polymer
backbone considerably limits the possibilities for further chemical
modification of polymer chains. To overcome this limitation
several approaches has been examined including modification of
lactide monomer, copolymerization with suitable comonomer or
blending. [2]
Our goal was to develop convenient synthetic procedures
for the synthesis of functionalized PLA using “metal-free”
catalysts and initiators. Polymers of lactide containing at one or
both ends reactive groups that may be used as precursors of
segments in block copolymers or side-chains in graft copolymers
can be obtained by cationic activated monomer polymerization. [3]
Using functionalized alcohols as initiators we obtained PLA
macromonomers carrying unsaturated – (meth)acrylate and
propargyl groups at one chain end. One-pot synthesis based on
easy available acid and alcohols prevents the possible
contamination of the final products with metallic initiators or
catalyst residues.
The reactivity of functional groups (containing double or
triple bonds) was confirmed by radical (co)polymerization of
macromonomers or by performing azide-alkyne “click” reaction
with model azide. [4]
PLA containing pendant reactive groups was obtained in
cationic copolymerization of lactide with epichlorohydrin. The
postpolymerization modification based on these functional
polymers may provide entry to expand the application of PLA.
Acknowledgement: Financial support by the project POIG.
01.01.02-10-123/09-01, acronym BIOMASA is gratefully
acknowledged
references:
1. A. C. Albertsson, J. Polym. Sci. Part A: Polym. Chem. 48,
1214, 2010
2. M. Weck et al. Biomacromolecules 7, 1735, 2006
3. P. Kubisa, S. Penczek, Prog. Polym. Sci. 24, 1409, 1999
4. M. Basko, M. Bednarek, Reactive and Functional Polymers.
72, 213, 2012
Keywords: polymerization;
4 th EucheMs chemistry congress
P - 0 2 8 8
SyntheSiS of trAditionAL MediCinAL funGAL
MetABoLiteS.
A. BeeKMAn 1 , r. BArrow 1
1 Australian National University, Research School of Chemistry,
Canberra ACT, Australia
In 2009 Proksch et al. isolated a number of biologically
active fungal metabolites from a Pestalotiopsis sp. of fungi,
discovered in the medicinal plant Rhizopora mucronata, a
mangrove found in southern China. [1] The biologically active
compounds isolated from the endophytic fungi, may prove to be
drug leads which have a history of internal use (non-toxic) and
demonstrated activity. Two classes of compounds isolated by
Proksch were of particular interest. The pestalotiopsones are a
collection of chromone derivatives featuring an alkyl group at
C-2 and a carboxyl group at C-5. 1a Compounds with this
substitution pattern are part of a rare subtype of chromones found
in nature, with only three previously recorded members. [2]
The cytosporones are a group of 3-isochromanones, which are
relatively scarce in the natural products literature, possessing an
alkyl group at C-2 and varying oxygenation of the aromatic ring. 1b
The specific rotations of the natural products containing
chirality were measured, although the absolute stereochemistry
of the compounds was not determined. Synthesis of these
compounds is yet to be reported in the literature. This presentation
will describe the work leading to the first syntheses of these
natural products, and the determination of the absolute
stereochemistry of the natural compounds.
references:
1. a) Proksch, P., et al., J. Nat. Prod. 2009, 72, 662-665.
b) Proksch, P., et al., Bioorg. Med. Chem. 2009, 17,
7362–7367.
2. Kashiwada, Y., et al., Chem. Pharm. Bull. 1984, 32,
3493–3500;
Graziani, E. I., et al., J. Nat. Prod. 2005, 68, 1262-1265;
Kalaitzis, J. A.; Moore, B. S., J. Nat. Prod. 2004, 67,
1419–1422.
Keywords: Total synthesis; Natural products; Drug discovery;
Heterocycles; Microwave chemistry;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc