Preparation of azacrown-functionalized 2 '-O-methyl oligoribonucleotides, potential artificial RNases
: Niittymaki T, Kaukinen U, Virta P, Mikkola S, Lonnberg H
Publisher: AMER CHEMICAL SOC
: 2004
: Bioconjugate Chemistry
: BIOCONJUGATE CHEMISTRY
: BIOCONJUGATE CHEM
: 15
: 1
: 174
: 184
: 11
: 1043-1802
DOI: https://doi.org/10.1021/bc034166b
An improved synthesis for 3-(3-aminopropyl)- and 3-(3-mercaptopropyl)-1,5,9-triazacyclododecane has been developed and alternative methods for their conjugation to oligonucleotides have been described. Accordingly, the 3-aminopropyl azacrown and its N-(3-aminopropanoyl)-3-aminopropyI analogue have been tethered to the X-terminus of a 2'-O-methyloligoribonucleotide by aminolytic cleavage of the thioester linker utilized for the chain assembly. Studies on a monomeric model compound verify that the reaction proceeds solely by the attack of the primary amino group. 5'-Conjugation has been achieved by introducing a 2-benzylthio-2-oxoethyl group to the 5'-terminus as a phosphoramidite reagent and cleaving the thioester bond with the 3-aminopropyl azacrown. For intrachain conjugation, a phosphoramidite reagent derived from 1-deoxy-1-(2-benzylthio-2-oxoethyl)-beta-D-erythro-pentofuranose has been inserted in a desired position within the chain and subjected to on-support aminolysis with the 3-aminopropyl azacrown or its N-(3-aminopropanoyl)-3-aminopropyI and N-(6-aminohexanoyl)3-aminopropyl analogues. The 3-mercaptopropyl-derivatized azacrown has been tetherd by a disulfide bond to a 3'-(3-mercaptoalkyl)phosphate-tailed oligonucleotide. The 3'- and intrachain-tethered conjugates have been shown to cleave as their Zn(II) chelate complementary oligoribonucleotide sequences.