A mixture of 3-amino-5-(5-methyl-1H-pyrazol-4-yl)thiophene-2-carboxamide (111 mg, 0.50 mmol), 1-(2-pyridyl)-piperidin-4-one (264 mg, 1.50 mmol), CSA (11.6 mg, 0.05 mmol), MgSO4 (120 mg, 1.00 mmol) and DMA (4 mL) was stirred at 100° C. for 1 h. The mixture was poured into saturated aqueous NaHCO3 and extracted with 3:1 EtOAc/THF, and the extract was dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by column chromatography (Purif, silica gel, EtOAc to 80:20 EtOAc/MeOH). The obtained yellow solid (190 mg) was triturated with MeOH/EtOAc and collected by filtration to afford the title compound (147 mg, 77%) as a pale yellow solid:
