N-bromobutanimide → 8-Bromo-2-[(tetrahydro-2-furanylmethyl)oxy]-9-(tetrahydro-2H-Pyran-2-yl)-9H-purin-6-amine

2-[(Tetrahydro-2-furanylmethyl)oxy]-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (1.7202 g) was dissolved in chloroform (15 mL) and cooled to ˜1° C. before N-bromosuccinimide (1.056 g) was added keeping the reaction temperature below 2° C. The reaction mixture was then stirred at ˜1° C. for 30 minutes before allowing to warm to room temperature were upon the reaction mixture was stirred for 3 hours. The reaction mixture was then stood overnight at room temperature before being partitioned between water (50 mL) and the organic phase separated using a hydrophobic frit. The organic phase was evaporated under reduced pressure to give a brown gum which was purified using silica chromatography (ISCO) eluting with 0-100% ethyl acetate: cyclohexane. This gave the title compound as a white foam solid (1.3748 g).