89872-97-9Relevant articles and documents
Oligonucleotides Composed of 2′-Deoxy-1′,5′-anhydro-D-mannitol Nucleosides with a Purine Base Moiety
Hossain, Nafizal,Wroblowski, Berthold,Van Aerschot, Arthur,Rozenski, Jef,De Bruyn, Andre,Herdewijn, Piet
, p. 1574 - 1582 (2007/10/03)
2′-Deoxy-D-mannitol nucleosides with a purine base moiety have been conveniently synthesized starting from 1,5-anhydro-4,6-O-benzylidene-D-glucitol. The 3-OH function of 1,5-anhydro-4,6-O-benzylidene-D-glucitol was selectively protected with tert-butyldimethylsilyl group, and the 2′-OH function was subsequently converted to the corresponding O-triflate derivative for the introduction of the nucleobase moieties. These nucleoside derivatives were transformed to 1,5-anhydro-4-O-(P-(2-cyanoethyl)-P-(N,N-diisopropylamino)phosphinyl)-2-deoxy-6- O-monomethoxytrityl-3-O-(tert-butyldimethylsilyD-D-mannitol with either a 2-(N6-benzoyladenin-9-yl) or a 2-(N2-isobutyrylguanin-9-yl) substituent as the building blocks for oligonucleotide synthesis. The corresponding fully modified oligonucleotides afford considerably less stable duplexes with RNA as compared to the 3-deoxy hexitol nucleic acid analogues described previously. The reason for the lower stability was investigated using molecular modeling. MD simulations of single strand MNA(GCGTAGCG) and MNA(GCGTAGCG) complexed with RNA(CGCAUCGC) in aqueous solution were performed by use of AMBER 4.1 with the particle mesh Ewald (PME) method for the treatment of long-range electrostatic interactions. Frequent hydrogen bonds between the 3′-hydroxyl and the 6′-O of the phosphate backbone of the following base changed the conformation of the single strand as well as the MNA:RNA complex. The MNA:RNA backbone widens up and shows partial unwinding and disruption of base pair hydrogen bonds consistent with their low hybridization potential.
Out-of-Ring Claisen Rearrangement are Highly Stereoselective in Pyranoses: Routes to gem-Dialkylated Sugars
Tulshian, Deen Bandhu,Tsang, Raymond,Fraser-Reid, Bert
, p. 2347 - 2355 (2007/10/02)
The Claisen rearrangement has been evaluated as a means for stereoselective creation of functionalized geminal substituents at C-2 and C-3 of hexopyrano systems.C-2 and C-3 keto sugars react with Wittig reagents to give α,β-unsaturated esters, one geometric isomer being obtained in each case.Reduction of the ester and trans vinylation with ethyl vinyl ether leads to allyl vinyl ethers wich are thermolysed in refluxing benzonitrile.The oxy-Cope rearrengement proceeds with complete stereoselectivity, the folding pattern being always from the β-face of the pyranose ring.Thus, the acetaldehyde moiety ends up axially oriented at C-2 and equatorially oriented at C-3.These stereochemical results are not affected by neighboring oxygen substituents nor by the presence or absence of an anomeric alkoxyl functionality.