1-(4-methoxycarbonylphenyl)-5-propylsulfanyl-pyrazole-4-carboxylic acid (Intermediate #7) (160 mg, 0.5 mmol), 1-adamantylamine (76 mg, 0.5 mmol), HOBT (81 mg, 0.6 mmol) and DIPEA (174 μL, 1.0 mmol) were dissolved in DMF (5 mL) and treated at ambient temperature with EDCI (115 mg, 0.6 mmol). The mixture was stirred at ambient for 18 h and then diluted with ethyl acetate (50 mL), washed with water (3×20 mL) and brine, dried (MgSO4) and volatiles removed by evaporation. The residue was purified by chromatography on silica gel (12 g silica 0-50% EtOAc/isohexane) to give the title compound as a colourless gum (143 mg, 63%).
