Studies on transfer ribonucleic acids and related compounds. XLV. Block condensation of ribooligonucleotides containing 2' -O-tetrahydrofuranyl-5' -O-dimethoxytritylnucleosides

Abstract

2′-O-Tetrahydrofurany1-5′-O-dimethoxytrityl-N-protected nucleosides were phosphorylated to give the 3′-(o-chlorophenyl) phosphates which were then condensed with 3′,5′-unprotected nucleosides to elongate the chain in the 3′-direction. The 5′-dimethoxytrityl group of these oligonucleotides was selectively deblocked by treatment with zinc bromide. The rate of removal of the dimethoxytrityl group differed in each nucleotide. A dodecamer containing a termination codon UAG, U(AGU)₃,AG, was synthesized by elongating the chain in the 5′-direction using the selective dedimethoxytritylation followed by condensation of protected oligonucleotide blocks.