Triethylamine → Ethyl 5-phenyl-4-propionylisoxazole-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-phenylpent-1-yn-3-one (36.7 mg, 0.232 mmol) and triethylamine (0.113 mL, 0.812 mmol) in toluene (1 mL) at 120° C. was added (Z)-ethyl 2-chloro-2-(hydroxyimino)acetate (105 mg, 0.696 mmol) in toluene (1 mL) dropwise. The reaction mixture was stirred at 120° C. for 16 h. To the reaction mixture was added additional (Z)-ethyl 2-chloro-2-(hydroxyimino)acetate (105 mg, 0.696 mmol) and triethylamine (0.113 mL, 0.812 mmol), and the reaction mixture was stirred at 140° C. for 3 days. The reaction mixture was concentrated, diluted with ethyl acetate (5 mL), washed with water (1 mL), washed with a saturated aqueous solution of sodium bicarbonate (1 mL), washed with brine (1 mL), and dried over anhydrous sodium sulfate. Concentration followed by purification by silica gel chromatography with hexanes/ethyl acetate (10/1) afforded ethyl 5-phenyl-4-propionylisoxazole-3-carboxylate (14.7 mg). The compound had an HPLC ret. time=3.15 min.−Column: YMC S5 COMBISCREEN® 4.6×50 mm; Gradient time: 4 min; Flow rate=4 ml/min; Solvent A=10% MeOH−90% Water−0.2% H3PO4; Solvent B=90% MeOH−10% water−0.2% H3PO4; Start % B=0; Final % B=100. LC-MS: 274+.

Provenance & Evidence