p-Toluenesulfonic acid → HCID 69072799, compound

Participants

Reaction Steps

1.48 g (7.97 mmol) of 1-(t-butoxycarbonyl) piperazine, 0.74 ml (9.59 mmol) of diketene and 0.22 ml (1.58 mmol) of triethylamine were stirred in 50 ml of toluene at 80° C. for 5 hours. After ethyl acetate was added, the reaction mixture was washed with saturated aqueous sodium hydrogencarbonate solution. The organic layer was dried over anhydrous sodium sulfate and then concentrated under reduced pressure. The obtained substance was dissolved in 50 ml of benzene. 0.94 ml (8.30 mmol) of 3-chlorobenzaldehyde, 0.08 ml of piperidine and catalytic amount of p-toluenesulfonic acid were added and stirred removing water at 120° C. for 7 hours. After adding ethyl acetate, the reaction mixture was washed with 1 N hydrochloric acid and saturated aqueous sodium hydrogencarbonate solution. 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=3/1). The obtained substance was dissolved in 50 ml of 2-propanol. 929 mg (6.03 mmol) of 3-aminocrotonate (2-cyanoethyl) ester was added and stirred at 80° C. for four nights and then, after the solvent was removed, stirred at 120° C. for 4 hours. The reaction mixture was purified by the silica gel chromatography (chloroform/methanol=100/1) to obtain the title compound.

Provenance & Evidence