Acetic Acid → N-(1-Benzyl-4,4-diethoxy-piperidin-3-yl)-6-[2-ethyl-5-fluoro-4-(2-trimethylsilanyl-ethoxymethoxy)-phenyl]-1-(tetrahydro-pyran-2-yl)-1H-indazole-3-carboxamidine

Participants

Reaction Conditions

Reaction Steps

To a solution of 6-[2-ethyl-5-fluoro-4-(2-trimethylsilanyl-ethoxymethoxy)-phenyl]-1-(tetrahydro-pyran-2-yl)-1H-indazole-3-carboximidic acid methyl ester (Preparation 7, 17.15 g, 32.49 mmol) in ethanol (100 mL) was added a solution of 1-benzyl-4,4-diethoxy-piperidin-3-ylamine (Tetrahedron, 1995, 51, 13447-13454; 9.51 g, 34.2 mmol) in ethanol (70 mL). Acetic acid (3.56 mL, 62.1 mmol) was added and the reaction mixture was heated at 50° C. for 18 hours. The reaction mixture was concentrated in vacuo and the residue was partitioned between EtOAc (400 mL) and saturated sodium hydrogen carbonate aqueous solution (300 mL). The organic layer was washed with further saturated sodium hydrogen carbonate aqueous solution (300 mL). The combined aqueous layers were re-extracted with EtOAc (400 mL). The combined organic layers were dried over MgSO4 and concentrated in vacuo. The crude product was purified by column chromatography on silica gel eluting with DCM:methanol:ammonia (80:20:2) to give the title compound (11.31 g) in a 45% yield.

Provenance & Evidence