p-Toluenesulfonic acid → 6-chloro-2-methyl-9-(tetrahydro-2H-pyran-2-yl)-9H-purine

Participants

Reaction Conditions

Reaction Steps

6-Chloro-2-methyl-9H-purine (9.45 g, 56 mmol, the material from Step 2) was suspended in DCM (100 mL) and p-toluenesulfonic acid (Acros Organics, Geel, Belgium, 12% in acetic acid, 0.90 mL, 5.6 mmol) and 2,3-dihydropyran (6.6 mL, 73 mmol) were added. The reaction flask was fitted with a reflux condenser and placed in a preheated oil bath (50° C.) and stirred under nitrogen for 30 minutes. Then, the reaction was cooled to room temperature and stirred overnight. After stirring overnight, the reaction was diluted with DCM and treated with saturated sodium bicarbonate (75 mL). The layers were separated, and the aqueous phase was extracted with DCM. The organic extracts were combined, dried over sodium sulfate, filtered, concentrated, and dried under high vacuum at 45° C. (in a water bath) and then at room temperature and then at 60° C. and finally at room temperature again to afford 6-chloro-2-methyl-9-(tetrahydro-2H-pyran-2-yl)-9H-purine (13.73 g, 97% over 3 steps). MS (ESI pos. ion) m/z: 253. Calculated exact mass for C11H13ClN4O: 252. 1H NMR (CDCl3, 400 MHz) δ 8.26 (s, 1H), 5.78 (d, J=10.56 Hz, 1H), 4.19 (d, J=11.93 Hz, 1H), 3.84-3.76 (m, 1H), 2.80 (s, 3H), 2.20-1.96 (m, 3H), 1.89-1.64 (m, 3H).

Provenance & Evidence