Synthesis of the human insulin gene. Part III. Chemical synthesis of 5'-phosphomonoester group containing deoxyribooligonucleotides by the modified phosphotriester method. Its application in the synthesis of seventeen fragments constituting human insulin C-chain DNA.

A method for phosphorylating a protected deoxyribooligonucleotide containing phosphotriester linkages is described. The modified phosphotriester method of chemical synthesis is further refined in terms of (i) better final deblocking conditions and (ii) new chromatography solvent systems containing acetone-water-ethyl acetate to yield pure oligomers. The effectiveness of these improvements has been demonstrated in the rapid and efficient synthesis of seventeen fragments constituting the sequence of human insulin C-chain DNA.