Synthesis of nucleoside libraries on solid support. I. N2, N6-disubstituted diaminopurine nucleosides

Starting with 2‐iodo‐6‐chloro‐9‐(β‐D‐ribofuranosyl)purine, a library of more than 1,300 N2,N6‐polysubstituted diaminopurine nucleosides was created. The starting material was condensed with a polystyrene monomethoxytrityl resin and a pool of primary and secondary amines was used to displace the 6‐chloro atom with high regio‐selectivity. The 2‐iodo was subsequently displaced by various primary amines. Nucleosides were cleaved from the resin with hexafluoroisopropanol solutions. A majority of compounds reached a purity of more than 80% without the need for any type of purification. †In honor and celebration of the 70th birthday of Professor Leroy B. Townsend.