Convenient synthesis of 2,9-disubstituted guanines mediated by solid-supported reagents

A novel application has been developed to separate regioisomers chemoselectively using a solid-supported reagent. An N7/N9 purine regioisomer mixture was purified using aluminum oxide/H+ to provide the N9 isomer selectively as a parallel or high-throughput format (chemoselective high-throughput purification). 2,9-Disubstituted guanines were conveniently prepared by this new method in conjunction with solid-supported reagents.