p-Toluenesulfonic acid → 1-[(S)-4-(4-Chloro-2-fluoro-5-methoxy-phenyl)-2-methyl-piperazin-1-yl]-2-(3-[1,2,4]oxadiazol-3-yl-pyrazolo[3,4-b]pyridin-1-yl)-ethanone

Participants

Reaction Conditions

Reaction Steps

A mixture of 1-{2-[4-(4-Chloro-2-fluoro-5-methoxy-phenyl)-2-methyl-piperazin-1-yl]-2-oxo-ethyl}-N-hydroxy-1H-pyrazolo[3,4-b]pyridine-3-carboxamidine (1.2 g), trimethyl orthoformate (20 ml) and para-toluene sulfonic acid (PTSA) (0.1 g) was stirred at 100° C. overnight. The reaction mixture was concentrated in vacuo to provide a crude residue which was purified by flash chromatography to provide 1-[(S)-4-(4-Chloro-2-fluoro-5-methoxy-phenyl)-2-methyl-piperazin-1-yl]-2-(3-[1,2,4]oxadiazol-3-yl-pyrazolo[3,4-b]pyridin-1-yl)-ethanone (0.7 g). LCMS Retention time: 2.61 min (Agilent Zorbax SB-C18, 2.1×50 mm, 5μ, 35° C.) using 1 ml/min flow rate, a 2.5 minute gradient of 20% to 100% B with a 1.1 minute wash at 100% B (A=0.1% formic acid/5% acetonitrile/94.9% water, B=0.1% formic acid/5% water/94.9% acetonitrile). LCMS observed for (M+H)+: 486.

Provenance & Evidence