A mixture of 4-(5-methyl-tetrazol-1-yl)-phenol (Chembridge Corporation, San Diego, Calif., USA; 76 mg, 0.43 mmol), 4-chloro-1-[4-(3-isopropyl-[1,2,4]oxadiazol-5-yl)-trans-cyclo-hexyl]-1H-pyrazolo[3,4-d]pyrimidine (Intermediate 26; 150 mg, 0.43 mmol), and potassium carbonate (72 mg, 0.52 mmol) in dimethylformamide (5 mL) was heated in a microwave at 180° C. for 10 min. The mixture was filtered. The filtrate was concentrated and purified using a Supelco 23 g column, eluting with 0-3% methanol/dichloromethane to give 1-[4-(3-isopropyl-[1,2,4]oxadiazol-5-yl)-trans-cyclohexyl]-4-[4-(5-methyl-tetrazol-1-yl)-phenoxy]-1H-pyrazolo[3,4-d]pyrimidine (86 mg, 41%).
