112233-76-8Relevant academic research and scientific papers
Nucleotides. LXXIV* synthesis of α-D-arabino-oligonucleotides
Henke, Christoph,Pfleiderer, Wolfgang
, p. 1665 - 1706 (2007/10/03)
□ The 5 α-D-arabinofuranosylnucleosides α-araU (15), α-araT (18), α-araC (22), α-araA (25), and α-araG (28) have been synthesized by the modified silyl-method. The amino groups at the nucleobases and the 2′-hydroxy group at the sugar moiety were protected by the 2-(4-nitrophenyl)ethoxycarbonyl (npeoc) group (37-40) and the amide function in α-araG was additionally blocked by the 2-(4-nitrophenyl)ethyl group (63) to improve solubility in organic solvents. Mono-and dimethoxytritylation of the 5′-OH group was performed in the usual manner to give 41-48, 64, and 65 in high yields and further substitution of the 3′-OH group led to the monomeric building blocks 66-75 as well as the 3′-O-succinoyl derivatives 76-85 functioning as starting units in solid-support oligonucleotide synthesis. A large number of oligo-α- arabinonucleotides have been prepared on modified CPG-material applying the npeoc/npe strategy as a very efficient synthetic tool for highly purified, homogenous oligomers. Hybridizations between α-arabinonucleotide strands revealed in analogy to earlier findings an antiparallel orientation whereas the combination of an oligo-α-D-arabinonucleotide with a complementary oligo-2′-deoxy-β-D-ribofuranosylnucleotide showed base-pairing only if a parallel polarity was present. The advantages in oligo-α-arabino- nucleotide synthesis were furthermore demonstrated by the synthesis of the tα-ANAhis a structural analog of the natural tRNAhis of the phage T5. Copyright Taylor & Francis Group, LLC.
Nucleic acid related compounds. 93. A solution for the historic problem of regioselective sugar-base coupling to produce 9-glycosylguanines or 7-glycosylguanines
Robins, Morris J.,Zou, Ruiming,Guo, Zhiqiang,Wnuk, Stanislaw F.
, p. 9207 - 9212 (2007/10/03)
Per(trimethylsilyl)-2-N-acylguanine derivatives and tetra-O-acylpentofuranoses were coupled [tin(IV) chloride or titanium(IV) chloride catalysis] to give predominant formation of 7-glycosylguanines. With TiCl4, a fortuitous organic/aqueous partitioning allowed isolation of 7-glycosylguanines from the 7/9 isomer mixtures. Per(trimethylsilyl)-2-N-acyl-6-O-(diphenylcarbamoyl)guanine derivatives and tetra-O-acylpentofuranoses underwent regioselective coupling (trimethylsilyl trifluoromethanesulfonate catalysis) to give 9-glycosylguanines. The 6-O-(diphenylcarbamoyl)peracyl-9-β-D-ribofuranosyl isomer was shown to be both the xinetic and thermodynamic coupling product. Deprotection of all of the peracyl coupling products was effected under mild conditions to give good to high yields of guanine nucleoside analogues. These methodologies provide solutions for the regioselective synthesis of 7- and 9-glycosylguanine nucleosides.
