A convenient approach to the synthesis of trinucleotide phosphoramidites - Synthons for the generation of oligonucleotide/peptide libraries

Trinucleotide phosphoramidites that correspond to the codons of all 20 amino acids were synthesized in high yield in 5g scale, Precursors of those amidites-trinucleotide phosphotriesters-have been prepared using the phosphotriester approach without protection of the 3'-hydroxyl function, The structures of trinucleotide phosphotriesters and intermediates were confirmed by H-1- and P-31-NMR spectra, mass-spectra and by analysis of SPDE-hydrolysates of deprotected preparations, Purity of the target products has been confirmed by test reactions, The synthons have been used for automated synthesis of oligonucleotides and corresponding libraries by a phosphite-triester approach, A 54mer, containing 12 randomized internal bases, and a 72mer with 24 internal randomized bases have been synthesized.