tert-butyl 4,5-dihydro-1H-pyrazolo[3,4-c]pyridine-6(7H)-carboxylate

871726-72-6

871726-73-7

General procedure for the synthesis of tert-butyl 4,5-dihydro-1H-pyrazolo[3,4-c]pyridine-6(7H)-carboxylate from tert-butyl 4-((dimethylamino)methylene)-3-oxopiperidine-1-carboxylate: to a stirred tert-butyl 4-((dimethylamino)methylene)-3-oxopiperidine-1-carboxylate (1.0 g, 4 mmol) ethanol (EtOH. 10 mL) solution was added to hydrazine hydrate (376 mg, 10 mmol). The reaction mixture was stirred at 80 °C for 16 h until liquid chromatography-mass spectrometry (LCMS) analysis showed that the reaction was complete. After completion of the reaction, the mixture was concentrated and the residue was diluted with water (30 mL) and extracted with ethyl acetate (EA, 3 x 30 mL). The organic phases were combined, washed with brine (20 mL), dried over anhydrous sodium sulfate (Na2SO4) and concentrated. The resulting residue was used directly in the next step of the reaction (810 mg, 90% yield).LCMS data: 224.1 (M + 1), 114.1 (M + 1-100), 168.1 (M + 1-56).