2-O-tert-Butyldimethylsilyl-4,6-O-ethylidene-myo-insitol 1,3,5-orthoformate

In the title compound, C₁₅H₂₆O₆Si, the dioxa six-membered ring bonded to the myo-inositol skeleton is in a boat conformation while the rest of the six-membered rings adopt chair conformations.

2'-O,4'-C-Methylene bridged nucleic acid (2',4'-BNA): synthesis and triplex-forming properties

For development of ideal antisense and antigene molecules, various chemical modifications of oligonucleotides have been studied. However, despite their importance, there is only limited information available on the triplex-forming ability of the conformationally restricted or locked oligonucleotides. We report herein that 2'-O,4'-C-methylene bridged nucleic acid (2',4'-BNA) modification of triplex-forming oligonucleotide (TFO) significantly enhances the binding affinity towards target dsDNA. On Tm measurements, the triplex with the 2',4'-BNA oligonucleotides were found to be stabilized with deltaTm/modification of +4.3 to +5 degrees C at pH 6.6 compared to the triplexes with the unmodified oligonucleotide. By means of gel-retardation assay, the binding constant of the 2',4'-BNA oligonucleotide at pH 7.0 was at least 300-fold higher than that of the natural oligonucleotide. In addition, the 2',4'-BNA oligonucleotide clearly showed the inhibition of the NF-kappaB transcription factor (p50)-target dsDNA binding by forming a stable triplex at pH 7.0.

Chelation-Assisted C-O Bond Cleavage of Ortho Esters. A Convenient Synthesis of myo-Inositol Derivatives Having Free Hydroxy Group(s) at Specific Position(s)

Reactions of ortho esters of myo-inositol 8 or 10 with 1-2 equiv of Grignard reagents in benzene-ether yield regio- and stereoselectively the corresponding ring opening products having a free hydroxy group at C-1. The regioselectivity is rationalized owing to the presence of the 2-methoxy group which will serve as an auxiliary to form a chelation complex 12 with magnesium. Inositol derivatives having two free hydroxy group at C-1 and C-3 positions can be achieved from reactions of 6 or 8 with excess Grignard reagents or under more drastic conditions. The reaction of 8b with excess LiAlH(4)/AlCl(3), on the other hand, yields the corresponding 1,5-diol 19.