Diethyl Ether → 4-{5-[3-(5-tert-Butyl-2-p-tolyl-2H-pyrazol-3-yl)-ureido]-6-methyl-pyridin-2-yl}-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

Heat a solution of 4-(5-amino-6-methyl-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester (Preparation 3, 41.20 g, 140.9 mmol), (5-tert-butyl-2-p-tolyl-2H-pyrazol-3-yl)-carbamic acid, 2,2,2-trichloro-ethyl ester (Preparation 38, 57.03 g, 140.9 mmol), and DIEA (36.8 mL, 211.4 mmol) in DMSO (500 mL) at 60-65° C. for 2.5 hours. Add additional DMSO (100 mL) during the last 30 min to the thick slurry. Cool the slurry to room temperature and allow to stand overnight. Add diethyl ether (600 mL) and stir the slurry for 1 hour at room temperature. Filter and wash with diethyl ether (5×300 mL) then air-dry to afford a white solid (68.70 g, 89% yield uncorrected for DMSO—contains ca. 85 mol % of DMSO. LCMS(ES+): m/z=548 [M+H].

Provenance & Evidence