ethyl 5-(1-isopropyl-1H-pyrazol-5-yl)-3,6-dihydro-2H-pyran-4-carboxylate → (+/-) (3S,4R)-ethyl 3-(1-isopropyl-1H-pyrazol-5-yl)tetrahydro-2H-pyran-4-carboxylate

Participants

Reaction Steps

To a solution of ethyl 5-(1-isopropyl-1H-pyrazol-5-yl)-3,6-dihydro-2H-pyran-4-carboxylate (100 mg, 0.38 mmol) in EtOH (2 mL) was added Pd/C (50 mg), then it was charged with H2 (1 atm) and stirred at room temperature for 3 days, Mass spec shows about 50% conversion. The mixture was then added a solution of NH4CO2H (200 mg) in water (2 ml) and additional Pd/C, and the mixture was further heated at 75° C. for 1.5 h, after cooled to room temperature, the reaction was diluted with EtOH, pd/C was filtered off, and the filtrate was concentrated to give crude oil, which was diluted with CHCl3, organic layer was washed with Sat. NaHCO3, dried and concentrated to give crude product, which was purified by column (Hexanes/EtOAc=65:35) to give (±)ethyl(3S,4R)-3-(1-isopropyl-1H-pyrazol-5-yl)tetrahydro-2H-pyran-4-carboxylate (70 mg).

Provenance & Evidence