Triethylamine → 1-p-Tolyl-3-(t-butyldimethylsiloxy)-2-pyrazoline

Participants

Reaction Conditions

Reaction Steps

To a stirred solution under nitrogen of 1-p-tolyl-3-pyrazolidinone (52.8 g, 0.30 mole) in 500 ml toluene and 50 ml anhydrous tetrahydrofuran was added sequentially t-butyl-dimethylsilyl chloride (49.5 g, 0.30 mole), triethylamine (33.0 g, 0.30 mole), 4-(N,N-dimethylamino)pyridine (0.1 g) and 1,8-diazabicyclo[5.4.0]-undec-7-ene (0.1 g). The mixture was refluxed for 3 hours, then cooled to 30° C., and filtered. After the solids were washed with ether, the solvents of the combined filtrate were removed under reduced pressure. The resulting solid was dissolved in 500 ml anhydrous ether and filtered to remove salts. Removal of the solvent of the filtrate yielded 85.6 g (98% yield) of 1-p-tolyl-3-(t-butyldimethylsiloxy)-2-pyrazoline.

Provenance & Evidence