tert-butyl 4-((3-iodo-1-isopropyl-1H-pyrazol-4-yl)methyl)-4-isocyanatopiperidine-1-carboxylate → Tert-butyl 2'-isopropyl-7'-oxo-2',4',6',7'-tetrahydrospiro[piperidine-4,5'-pyrazolo[3,4-c]pyridine]-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a −78° C. solution of tert-butyl 4-((3-iodo-1-isopropyl-1H-pyrazol-4-yl)methyl)-4-isocyanatopiperidine-1-carboxylate (280 mg, 0.59 mmol) in tetrahydrofuran (10 mL) was added t-butyl lithium (0.7 mL, 1.7 M in pentane), dropwise. After stirring for 30 minutes at −78° C. the mixture was warmed to 0° C., quenched with 20 mL saturated aqueous ammonium chloride, and stirred an additional 30 minutes at room temperature. The reaction mixture was diluted with 25 mL water and extracted with ethyl acetate (2×50 mL). The combined organics were dried over sodium sulfate, filtered and concentrated. The residue was then purified by flash chromatography (12-100% ethyl acetate/heptanes, 10 g silica gel) to yield tert-butyl 2′-isopropyl-7′-oxo-2′,4′,6′,7′-tetrahydrospiro[piperidine-4,5′-pyrazolo[3,4-c]pyridine]-1-carboxylate (130 mg) as a colorless solid. +ESI (M+H) 349.1; 1H NMR (500 MHz, CDCl3, δ): 7.28 (s, 1H), 5.78 (s, 1H), 4.57 (spt, J=6.6 Hz, 1H), 3.59 (m, 2H), 3.37 (m, 2H), 2.82 (s, 2H), 1.74 (m, 4H), 1.55 (d, J=6.6 Hz, 6H), 1.47 (s, 9H).

Provenance & Evidence