01691nas a2200193   4500008004100000022001400041245010700055210006900162260010600231300001400337490000700351520088300358653002701241653001301268653003601281100002201317700002601339856013201365       2013                        eng d  a0040-402000aSynthesis and properties of 2 `-O-[R- and S-(2-amino-3-methoxy)propyl] (R-AMP and S-AMP) nucleic acids0 aSynthesis and properties of 2 OR and S2amino3methoxypropyl RAMP   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAUG  a6404-64080 v693 a<p>Substitution at 2'-position by either amino- or methoxy-pendant groups of the antisense oligonucleotides (AONs) is known to enhance their therapeutic value. A simple modification is described here in which we introduce both these groups in the form of enantiospecific tethers at 2'-position. Practical synthesis of modified nucleosides using natural L-serine, en route to R-AMP- and S-AMP-AONs is presented. Such tethered ONs formed stable DNA:RNA duplexes and the stability was found to be marginally better than the methoxyethyl/methoxypropyl-substituted MOE/MOP-AONs. The stereochemistry of the tether effectively differentiated the hydrolytic cleavage of AONs and the R-AMP-AON was three times more stable than the S-AMP-AONs after 4 h. In comparison, the MOE- or MOP-AONs were almost completely digested by SVPD after 1 h. (C) 2013 Elsevier Ltd. All rights reserved.</p>10aAntisense therapeutics10aMOE-AONs10aPositively charged ON analogues1 aKotikam, Venubabu1 aKumar, Vaijayanti, A.  uhttps://library.ncl.res.in/content/synthesis-and-properties-2-o-r-and-s-2-amino-3-methoxypropyl-r-amp-and-s-amp-nucleic-acids-0