Methyl iodide → 5-(tert-butyl-dimethyl-silanyloxymethyl)-1,4-dimethyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

A 1.5 M solution of tert-butyllithium in pentane (0.5 ml, 748 μmol) was added dropwise to a solution of 4-bromo-5-(tert-butyl-dimethyl-silanyloxymethyl)-1-methyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole (280 mg, 623 μmol; example 8 b]) in THF (2 ml) at −78° C. under an argon atmosphere. After 15 min methyl iodide (177 mg, 1.2 mmol) was added at −78° C. The reaction mixture was stirred for another 30 min at −78° C. and then for 2 h at RT. After quenching with saturated aqueous NaHCO3 solution the reaction mixture was partitioned between tert-butyl methyl ether and water. The ether phase was dried over sodium sulfate and concentrated in vacuo to give 240 mg (620 μmol, quant.) 5-(tert-butyl-dimethyl-silanyloxymethyl)-1,4-dimethyl-3-(4-trifluoromethyl-phenyl)-1H-pyrazole as yellow oil which was used in the next step without further purification.

Provenance & Evidence