Hydrochloric Acid → HCID 69278463, compound

Participants

Reaction Steps

4-Tert-butylphenyl isocyanate (350 mg, 2 mmol) was added to a solution of compound R (420 mg crude product, approx. 2 mmol) in abs. THF (20 ml) under argon at RT within 10 min. After 1 h the cloudy solution was mixed with triethylamine (0.3 ml, 2.22 mmol). The reaction mixture was stirred for a further 2 h and then mixed with 2 N HCl solution (10 ml). The acidic reaction mixture was stirred for 10 min and then extracted with EtOAc (3×20 ml). The combined organic phases were washed with sat. Na2HCO3 solution (10 ml), dried over Na2SO4 and concentrated to dryness under vacuum. The residue was recrystallised from toluene (15 ml). The desired product N-(4-tert-butylphenyl)-3-phenyl-1-oxa-2,7-diazaspiro[4.4]non-2-ene-7-carboxamide was thus obtained in a yield of 415 mg (55%) having a melting point of 207-208° C. (from EtOH, crystal transformation between 183 and 188° C.).

Provenance & Evidence