3,4-dihydro-2H-pyran → HCID 131727353, compound

Participants

Reaction Conditions

Reaction Steps

4-Bromo-5-(tert-butyl-dimethyl-silanyloxymethyl)-1H-pyrazole (1 g, 3.45 mmol) is dissolved in 3,4-dihydro-2H-pyran (0.944 mL, 10.34 mmol) in the presence of a catalytic amount of TFA (0.0026 mL, 0.035 mmol). The reaction mixture is stirred at 90° C. for 18 hours, cooled and then quenched using NaH (4.69 mg, 0.206 mmol). After removing the solvent, the residue is purified by silica gel column chromatography eluting with a mixture of 95:5 petroleum ether-ethyl acetate, followed by 90:10 petroleum ether-ethyl acetate. The fractions containing the desired compounds are collected and concentrated in vacuo to afford 4-bromo-3-(tert-butyl-dimethyl-silanyloxymethyl)-1-(tetrahydro-pyran-2-yl)-1H-pyrazole and 4-bromo-5-(tert-butyl-dimethyl-silanyloxymethyl)-1-(tetrahydro-pyran-2-yl)-1H-pyrazole (724 mg, 56%).

Provenance & Evidence