| Current
Organic Chemistry
ISSN: 1385-2728
Current Organic Chemistry
Volume 12, Number 12, August 2008
Contents
Carbohydrate Chemistry
Guest Editor: Zbigniew J. Witczak
Editorial Pp. 972
Zamojski’s Total Synthesis of Racemic Monosaccharides
as an Inspiration for Stereoselective Transformations of Readily
Available Sugar Synthons Pp. 973-984
Marek Chmielewski, Sebastian Stecko and Wioletta
Kosnik
[Abstract]
From Higher Carbon Sugars to Carbocyclic Sugar Mimics
Pp. 985-994
Slawomir Jarosz
[Abstract]
Why is Ribose the Sugar Component of Nucleic Acids?
New Insights into Absolute Asymmetric Synthesis and Absolute
Enantioselective Separation Pp. 995-1003
Roman Bielski and Michal Tencer
[Abstract]
Effect of RP
and SP Phosphorothioate Substitution
at the Scissile Site on the Cleavage Activity of Deoxyribozyme
10-23 Pp. 1004-1009
Barbara Nawrot, Kinga Widera, Milena Sobczak,
Marzena Wojcik and Wojciech J. Stec
[Abstract]
Synthesis of Oligosaccharide Libraries by Random Glycosylation
Pp. 1010-1020
Joachim Thiem, Andreas Steinmann, Julian
Thimm and Nikolai Wollik
[Abstract]
Occurrence, Synthesis and Biosynthesis of Bacterial
Heptoses Pp. 1021-1039
Paul Kosma
[Abstract]
General Article
Formation and Decomposition of Potassium Potassides
Complexed Crown Ethers in Tetrahydrofuran Solution Pp.
1040-1049
Zbigniew Grobelny, Andrzej Stolarzewicz,
Marcin Szczepanski and Maria Sokól
[Abstract]
Abstracts
[Back to top]
Editorial
Welcome to the sixth issue of Current Organic Chemistry
devoted to carbohydrate chemistry.1-5
This special issue contains presentations from Memorial Symposium
organized during 233.th American
Chemical Society National Meeting on March 25-29, 2007, in
Chicago, Illinois, U.S.A. which was dedicated to the late
Professor Alexander Zamojski from Polish Academy of Sciences,
Warsaw, Poland, and organized by us.
The collection of reviews was contributed by internationally
recognized experts and compiled sequentially in order of their
importance and specificity of topics.
The first review, entitled “Zamojski’s Total
Synthesis of Racemic Monosaccharides as an Inspiration for
Stereoselective Transformation of Readily Available Sugar
Synthons” by Professor Marek Chmielewski and co-workers
Sebastian Stecko, Wioletta Kosnik (Institute of Organic Chemistry,
Polish Academy of Sciences, Warsaw, Poland), examines historically
significant information published thus far on the topic of
utilization of functionalized carbohydrate synthons as universal
templates to number of new analogs of isomeric monosaccharides.
The second review contribution by Professor Slawomir Jarosz
(Institute of Organic Chemistry, Polish Academy of Science,
Warsaw, Poland) describes a new carbohydrate chemistry challenge:
“From Higher Carbon Sugar Analogs to Carbocyclic
Sugar Mimics”. The review covers many various new
aspects of carbohydrate carbocycles as applied to synthetic
carbohydrate chemistry.
The fundamentally important topic of nucleic acids has been
an enduring theme in the life science of carbohydrate chemistry:
Drs. Roman Bielski and Michal Tencer (Value Recovery Inc.
Bridgeport NJ, U.S.A/Canada) set out the principles and procedures
for these endeavors and contribute an excellent review entitled
“Why is ribose sugar component of nucleic acids?
New Insights into Absolute Enantioselective Synthesis and
Separation”
Continuation of nucleic acid topics is a subject of highly
specialized review entitled: “Effect of Rp and Sp-phosphorothioate
substitution at the scissile site of the cleavage activity
of the Deoxyribozyme 10-23” by Professors Barbara
Nawrot and Wojciech J. Stec and co-workers Kinga Widera, Milena
Sobczak and Marzena Wojcik (Center of Molecular and Macromolecular
Studies of Polish Academy of Science, Lódz, Poland).
Random glycosylation topics is explored in very informative
review entitled: “Synthesis of Oligosaccharide Libraries
by Random Glycosylation” contributed by Professor
Joachim Thiem and co-workers Andreas Steinmann, Julian Thimm,
and Nicolai Wollik (University of Hamburg, Hamburg, Germany)
Finally, Professor Paul Kosma (University of Applied Life
Sciences and Natural Resources, Wien, Austria) contributes
a review of “Occurrence, Synthesis and Biosynthesis
of Bacterial Heptoses”. This critically important
topic is often unappreciated by synthetic carbohydrate chemists
and by highlighting the significance of these chemical classes
of carbohydrates should give a better understanding and appreciation
of carbohydrates.
I kindly thank all the authors for their diligent efforts
in producing such an informed and enlightened collection for
this special issue and I welcome suggestions and ideas for
topics of future issues.
Zbigniew J Witczak
Department of Pharmaceutical Sciences
Nesbitt School of Pharmacy, Wilkes University
Wilkes-Barre, Pennsylvania 18766
1. Curr. Org. Chem. 4, (5), 455, 2000.
2. Curr. Org. Chem. 4, (6), 565, 2000.
3. Curr. Org. Chem. 5, (12), 1177, 2001.
4. Curr.Org. Chem. 7, (1), 1, 2003.
5. Curr. Org. Chem. 8, (4), 1, 2004.
Waldemar Priebe
Dep. of Experimental Therapeutics
M.D. Anderson Cancer Center
The University of Texas, Houston, TX 77030
[Back to top]
Zamojski’s Total Synthesis of Racemic Monosaccharides
as an Inspiration for Stereoselective Transformations of Readily
Available Sugar Synthons
Marek Chmielewski, Sebastian Stecko and
Wioletta Kosnik
The present account reports on the E-α,β-unsaturated-δ-butoxycarbonyl-δ-hydroxy-aldehyde
(3), acetal hydroperoxide (4)
and α,β-unsaturated-δ-lactone
(5), obtained during Zamojski’s total
synthesis of carbohydrates. Properties of these and related
compounds, and their further applications in organic synthesis
are discussed.
[Back to top]
From Higher Carbon Sugars to Carbocyclic Sugar Mimics
Slawomir Jarosz
The convenient route (showing a historical background of the
co-operation between the author and late Professor Aleksander
Zamojski) to carbocyclic sugar mimics: derivatives of highly
oxygenated bicyclo[4.3.0]nonanes and bicyclo[4.4.0]decanes
from sugar chirons is presented. First, the paper describes
the stereoselective synthesis of higher carbon sugars (up
to 21 carbon atoms in the chain) starting from various simple
derivatives of carbohydrates such as: sugar phosphoranes and
phosphonates, sugar acetylenes, and finally sugar allyltins.
The latter turned to be convenient starting materials for
the preparation of highly versatile dienoaldehydes, via
a controlled fragmentation with elimination of the stannyl
moiety. These dienes were used for the stereoselective synthesis
of highly oxygenated carbo-bicyclic derivatives.
[Back to top]
Why is Ribose the Sugar Component of Nucleic Acids?
New Insights into Absolute Asymmetric Synthesis and Absolute
Enantioselective Separation
Roman Bielski and Michal Tencer
Consequences of a chiral influence consisting of
three independent factors orienting molecules are reviewed
and discussed. This influence may affect mutual orientation
of reacting molecules leading to absolute asymmetric synthesis.
It may also exert different orientation of opposite enantiomers
relative to a flat surface which can lead to absolute enantioselective
separation. Besides the obvious although not trivial possible
applicability in organic synthesis, such a process, when applied
to a mixture of monosaccharides may have consequences related
to the formation of enantiomerically pure ribose under prebiotic
conditions. It is shown that α
-DL-ribopyranose is the easiest racemic
monosaccharide to get separated to enantiomers.
[Back to top]
Effect of RP
and SP Phosphorothioate Substitution
at the Scissile Site on the Cleavage Activity of Deoxyribozyme
10-23
Barbara Nawrot, Kinga Widera, Milena Sobczak,
Marzena Wojcik and Wojciech J. Stec
The substrate specificity towards RNA/DNA chimeric oligonucleotide
containing stereodefined phosphorothioate bond of the RP
and SP configuration at the
scissile site was determined for the cleavage reaction catalyzed
by the deoxyribozyme 10-23. Single-turnover kinetics in the
presence of either Mg2+ or
Mn2+ was used to determine
the thio- and manganese rescue effects of the cleavage reaction.
The obtained results indicate that the unmodified substrate
and its SP thio-analog are
specifically and efficiently cleaved even at low metal ion
concentration (0.02 mM). By contrast, the presence of the
phosphorothioate bond of the RP
configuration at the scissile site caused complete resistance
of this substrate in the deoxyribozyme-mediated cleavage reaction
in a broad metal ion concentration (from 0.02 to 100 mM).
These findings indicate the lack of a direct metal ion coordination
to the non-bridging phosphate oxygens of the scissile phosphate
bond (no β
catalysis is observed). Plausible mechanism of this 10-23
deoxyribozyme-assisted catalysis reaction involves engagement
of the divalent metal cation in the coordination of the oxygen
of the 2’-OH group and migration of proton to the pro-RP
oxygen of the scissile phosphate.
[Back to top]
Synthesis of Oligosaccharide Libraries by Random Glycosylation
Joachim Thiem, Andreas Steinmann, Julian
Thimm and Nikolai Wollik
The biological importance and activity of glycostructures
in cellular interactions is focus of numerous investigations
to date. Aim is to probe the activity of diverse natural-
and non-natural glycoconjugates in order to identify and correlate
structure-activity relationships. The complexity of glycostructures
and their synthetic realization has been a major obstacle,
since synthetic methodologies are used on a case by case basis;
hence access to a variety of complex glycostructures has been
limited. Combinatorial chemistry is a powerful tool for the
study of structure-function relationship of e.g. proteins
and nucleic acids and small molecules, but has been little
regarded within the recent decade in the field of carbohydrate
chemistry. This paper focuses on combinatorial glycosylation
strategy attempts from partially protected glycosyl acceptors,
to the development of solution phase glyco-combinatorial chemistry
using entirely unprotected non-reducing acceptors to generate
random libraries of regioisomeric oligosaccharides.
[Back to top]
Occurrence, Synthesis and Biosynthesis of Bacterial
Heptoses
Paul Kosma
Heptoses are important higher-carbon sugars occurring in numerous
structural variations in several domains of the bacterial
cell wall, which are briefly summarized. Recent approaches
towards the chemical and chemo-enzymatic synthesis of these
microbial monosaccharides will be summarized as well as progress
made in the elucidation of two major biochemical pathways
involving the synthesis of heptose phosphates and nucleotide-activated
heptoses.
[Back to top]
Formation and Decomposition of Potassium Potassides
Complexed Crown Ethers in Tetrahydrofuran Solution
Zbigniew Grobelny, Andrzej Stolarzewicz,
Marcin Szczepanski and
Maria Sokól
This review systematizes the essential data on alkalide
solutions called also alkali metal solutions or blue solutions,
i.e. solutions of the salts containing alkali metal anions
(M-). It focuses particularly on the formation
and decomposition of potassium potassides as well as on the
equilibrium and non-equilibrium reactions occurring with the
participation of solvated electrons (e-), potassium
anions (K-) and potassium cations complexed crown
ethers (K+Ln,
where n = 1 or 2). An explanation is proposed of the puzzling
constancy of [e-] while [K-] decreases
in apparent contradiction of the law of mass action in the
reaction with an oxidant or during the self decomposition
of the solution.
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