Diisopropylethylamine → HCID 67321823, compound

Participants

Reaction Conditions

Reaction Steps

Hünig's base (1 mL, 5.73 mmol) was added to a solution of 1,1-dimethylethyl 4-[(5-cyano-2-hydroxyphenyl)amino]-1-piperidinecarboxylate (D32, 977 mg, 3.08 mmol) in dichloromethane (20 mL) at rt under argon. The reaction was cooled to 0° C. and triphosgene (373 mg, 1.26 mmol) was added. The reaction was then stirred for 30 min at 0° C. and quenched with saturated aqueous NaHCO3 (20 mL) before being partitioned between dichloromethane and water. The aqueous layer was extracted with dichloromethane (2×) and the combined organics were dried (Na2SO4) and concentrated by rotary evaporation to give a yellow oil. The crude residue was purified via chromatography (silica, Biotage 40+S column, dichloromethane to 0.5% ammonia/9.5% methanol/90% dichloromethane) to give 1,1-dimethylethyl 4-(5-cyano-2-methylidene-1,3-benzoxazol-3(2H)-yl)-1-piperidinecarboxylate (D33, 1.22 g, 92% yield, 82% purity by LC-MS) as a yellow oil.

Provenance & Evidence