Acetic Acid → 5-(1-Benzyl-piperidin-3-ylamino)-indazole-1-carboxylic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 1-benzyl-piperidin-3-one hydrochloride (116 g, 0.52 mol, 1.2 eq) and TEA (43.5 g, 0.43 mol, 1.0 eq) in DCE (800 mL) was stirred at 30° C. for 1 hour. Then 5-amino-indazole-1-carboxylic acid tert-butyl ester (100 g, 0.43 mol, 1.0 eq) and CH3COOH (25.8 g, 0.43 mol, 1.0 eq) were added and the reaction mixture stirred for 30 min. NaBH(OAc)3 (273 g, 1.29 mol, 3.0 eq) was then added in one portion and the mixture stirred at 30° C. for 16 hours. LC-MS showed complete conversion. The reaction mixture was diluted in DCM (1 L) and the organic layer washed with saturated NaHCO3 (800 mL×3) and H2O (500 mL×3), dried over Na2SO4 and concentrated under vacuum. The crude product was purified by column chromatography on silica gel using (DCM:MeOH=60:1) to give the 5-(1-benzyl-piperidin-3-ylamino)-indazole-1-carboxylic acid tert-butyl ester (131 g, 75%).

Herkunft & Nachweise