Ethyl chloroformate → Norcyclobenzaprine

Participants

Reaction Steps

20 ml of saturated aqueous sodium hydrogencarbonate solution was added to 2.467 g (7.91 mmol) of cyclobenzaprine hydrochloride in 20 ml of chloroform, and they were stirred at room temperature for 10 minutes. After extracting with chloroform, the organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure. 15 ml of toluene was added to the residue, and they were heated at 80° C. 4.0 ml (41.8 mmol) of ethyl chloroformate was added thereto, and they were stirred at 80° C. overnight. 4.0 ml (41.8 mmol) of ethyl chloroformate was added to the reaction mixture, and they were stirred under heating for 2 days. Water was added to the reaction mixture. After extracting with ethyl acetate, the organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The residue was purified by the silica gel chromatography (hexane:ethyl acetate=1:1). 11.4 ml of 1-butanol and 1.97 g (35.1 mmol) of powdery potassium hydroxide were added to the obtained product, and they were stirred under heating at 120° C. for 4 hours. The reaction mixture was poured in water at room temperature. After the extraction with chloroform, the organic layer was dried over anhydrous sodium sulfate and then concentrated under reduce pressure to obtain the title compound.

Provenance & Evidence