7057-09-2Relevant academic research and scientific papers
5-Deoxy glycofuranosides by carboxyl group assisted photoinduced electron-transfer deoxygenation
Bordoni, Andrea,de Lederkremer, Rosa M.,Marino, Carla
, p. 1703 - 1710 (2008/09/18)
In connection with the development of practical methods for the synthesis of deoxy sugars, a photoinduced electron-transfer (PET) reaction using 9-methylcarbazole (MCZ) as photosensitizer was applied to a 2-O-(3-trifluoromethyl)benzoylated derivative of d
Synthesis of sphingosine-1-phosphonate and homosphingosine-1-phosphonate
Tarnowski, Andrej,Retz, Oliver,Baer, Thomas,Schmidt, Richard R.
, p. 1129 - 1141 (2007/10/03)
In the first approach to homosphingosine-1-phosphonate, D-glucofuranose was selectively deoxygenated at C-5. Bond cleavage between C-1 and C-2 afforded a 5-deoxy-D-threopentose intermediate. (E)-Selective Wittig reaction with a C 14-chain gave a C19-intermediate, which was readily transformed into homosphingosine. Formation of a cyclic urethane containing the 3-amino and the 4-hydroxy group of the C19-intermediate permitted regioselective introduction of the phosphonate group at C-1, thus affording the target molecule after deprotection. In a second and shorter route, C 18-sphingosine was converted to a cyclic urethane containing the 2-amino and the 3-hydroxy group of the C18-chain. C1-Chain extension by a hydroxymethyl group by introduction of cyanide led to the same C19 cyclic urethane as obtained in the first route. Similarly, the C18 cyclic urethane led to the other target molecule, namely sphingosine-1-phosphonate. The third and shortest route to homosphingosine-1- phosphonate could be based on regioselective 1-O-tosylation of 1,2,3-(trihydroxy)octadec-4-ene. Transformation into a 1,2-epoxide, then combination of C1-chain extension and introduction of a phosphonate group with methylphosphonate as reagent, and finally azide introduction, led after functional group liberation to the target molecule. As shown, also truncated derivatives are readily accessible by this route. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Structural modifications of antisense oligonucleotides
Urban, Ernst,Noe, Christian R.
, p. 243 - 258 (2007/10/03)
Antisense oligonucleotides are efficient tools for the inhibition of gene expression in a sequence specific way. Natural oligonucleotides are decomposed rapidly in biological systems, which strongly restrict their application. In contrast, artificial oligonucleotides are designed to be more stable against degradation than the target mRNA, which results in a catalytic effect of the drug. Modification of the phosphate linkage has been the first successful strategy for antisense drug developments and Fomivirsene the first antisense drug in therapy. The launch of Fomivirsene has resulted in a revolutionary spin off to antisense research leading to a second generation of antisense oligonucleotides, which are stable against oligonucleotide cleaving enzymes. Among these, oligonucleotides bearing an alkoxy substituent in position 2′ were the most successful ones. The third generation of antisense oligonucleotides contains structure elements, which enhance the antisense action. Zwitterionic oligonucleotides show remarkable results, first, because the stability against ribozymes is largely increased, and secondly, because the electrostatic repulsion between the anionic sense and the zwitterionic antisense cords is minimized. Promising new target molecules in antisense reseach are oligonucleotide chimaeres, which enhance the antisense action (chimaeres with intercalators, chelators or polyamines) or enable an application as sequence specific detectors (chimaeres with biotin, fluorescein or radioligands).
Binding and catalysis by yeast aldose reductase: A substrate-analog approach with new aldose derivatives
Hadwiger, Philipp,Mayr, Peter,Tauss, Andreas,Stuetz, Arnold E.,Nidetzky, Bernd
, p. 1683 - 1686 (2007/10/03)
5-Deoxy-D-xylofuranose derivatives and a range of new 5,6-dideoxy analogs of D-glucofuranose bearing azido or fluoro substituents were synthesised and employed as substrates of the NADH-dependent aldehyde reduction catalysed by yeast aldose reductase. In
Reversible charge-accelerated oxy-cope rearrangements
Tsui, Hon-Chung,Paquette, Leo A.
, p. 9968 - 9977 (2007/10/03)
An asymmetric synthesis of the oxetane-containing norbornanone 23 and its coupling to trans-1-propenyllithium to give 24 are reported, in tandem with the preparation of the related alcohols 28 and 30. All three divinyl carbinols undergo anionic oxy-Cope rearrangement very rapidly at low temperature. Quenching of 24-K+ and 28-K+ under these conditions with water or various aqueous salt solutions results in protonation of the alkoxides. If these reaction mixtures are poured instead onto cold (O °C) silica gel, their sigmatropically related ketones are isolated in very good yield. Whereas the 24-K+?25-K+ equilibrium pair is not reactive to molecular oxygen, 30-K+ is directly converted into an α-hydroperoxy ketone under comparable conditions. These and additional observations are rationalized in the context of atropisomerism involving conversion of oxygen- up enolates, formed reversibly under kinetically controlled conditions, into their thermodynamically favored, more reactive oxygen-down conformers.
