Chemical synthesis of a tridecanucleoside dodecaphosphate sequence of SV40 DNA

Abstract

The preparation, by the phosphotriester approach, of d[C-T-A-T-T-C-C-A-G-A-A-G-T] from one tetranucleoside triphosphate and three trinucleoside diphosphate blocks is described. The use of the O-dibromomethylbenzoyl (DBMB) protecting group in oligodaoxyribonucleotide synthesis is described for the first time. Internucleotide linkages are protected by O-chlorophenyl groups which are finally removed by treatment with the N1,N1,N3,N3-tetramethylguanidinium salt of syn-4-nitrobenxaldoxime. The first phos-phorylation step (leading to phosphodiester intermediates) is carried out by treatment with O-chlorophenyl phosphorodi-(l,2,4-triazolide) followed by treatment with water and triethylamine. 1-Mesitylenesulphonyl-3-nitro-1,2,4-triazole (MSNT) is used as the activating agent in the second phos-phorylation step in which 5′-protected mono- and di-nucleotides are condensed with nucleoside building blocks containing unprotected 3′-hydroxy functions. © 1980 IRL Press Limited.