Nucleosides and Nucleotides. Part 18. p-nitrobenzenesulfonyl nitroimidazole as a new condensing agent in the triester synthesis of oligonucleotides

p-Nitrobenzenesulfonyl nitroimidazole (p-NBSNI) ( 5 ) has been shown to be an efficient and convenient condensing agent in the coupling of protected nucleotide fragments. Its utility has been demonstrated by a direct comparison with previously-described condensing agents in the synthesis of various di- and tetradeoxy-nucleotides.