Methyl iodide → HCID 18436986, compound

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 3-(4-benzyl-piperazin-1-yl)-1H-thieno[3,2-c]pyrazole (318.0 g, 1.07 mol) in THF (2.5 L) was added a mixture of potassium t-butoxide (134.4 g, 1.2 mol) in THF (1.5 L) dropwise over a period of 1 hour while keeping the reaction temperature below 25° C. After complete addition, the mixture was cooled to −30° C. and MeI (65.4 mL, 1.05 mol) was added dropwise over a period of 30 minutes. The mixture is then slowly warmed to room temperature overnight. To the reaction mixture is slowly added saturated NaHCO3 (1 L). The solution is then evaporated to remove the THF and the resulting aqueous mixture is taken up in EtOAc and washed with water and brine. The EtOAc extract is dried (Na2SO4), filtered and evaporated. The viscous concentrate is filtered through a silica gel plug with 1:1 EtOAc/heptane and evaporated yielding a viscous oil that is then dried under vacuum where it solidifies and yields 326.03 g (98%) as a 12:1 ratio of regioisomers in favor of the desired product.

Provenance & Evidence