3,4-dihydro-2H-pyran → HCID 178516157, compound

Participants

Reaction Conditions

Reaction Steps

3-(Trifluoromethyl)-1H-pyrazol-5-ol (5.0 g, 0.032 mole) which is known in the art and p-toluene-sulfonic acid monohydrate (0.08 g) were dissolved in ethyl acetate (30 mL) and warmed to 50° C. 3,4-Dihydro-2H-pyran (2.9 g, 0.034 mole) was slowly added over a 10 minute period. After stirring 30 minutes at 50° C., the mixture was cooled and diluted with 100 mL of ethyl acetate. This solution was washed twice with 0.5% hydrochloric acid solution, then dried with magnesium sulfate, filtered and concentrated in vacuo. The residue was treated with 5 mL of ethyl acetate and 20 mL hexanes and filtered to give 1-(tetrahydro-2H-pyran-2-yl)-3-(trifluoromethyl)-1H-pyrazol-5-ol (5.8 g, 76% yield) as a white solid, mp=129°-130° C.

Provenance & Evidence