A mixture of (7-iodo-pyrazolo[1,5-a]pyridin-4-yl)-carbamic acid tert-butyl ester (36 mg, 0.1 mmol), zinc cyanide (24 mg, 0.2 mmol), tetrakis(triphenylphosphine) palladium (0) (23 mg, 0.02 mmol), and anhydrous DMF (1 mL) was degassed with argon. Then, the mixture was stirred at 80° C. for 4.5 h, cooled to rt, mixed with EtOAc (6 mL), and filtered. The filtrate was concentrated under reduced pressure. Purification by silica gel flash chromatography eluting with EtOAc/heptane (gradient from 1:4 to 1:2 ratio) gave compound 777E (24 mg, 93%) as a white solid. HPLC: 93% at 3.64 min (retention time) (YMC S5 ODS-A column 4.6×50 mm eluting with 10-90% aqueous methanol over 4 mincontaining 0.2% phosphoric acid, 4 mL/min, monitoring at 220 nm). MS (ES): m/z 259 [M+H]+.
