Sodium hydride → 3-Oxo-4-(2-pyrrolidin-1-yl-ethyl)-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Sodium hydride (55% dispersion in mineral oil, 1.96 g, 45 mmol) was added portionwise at room temperature to a solution of 3-oxo-piperazine-1-carboxylic acid tert-butyl ester (6.01 g, 30.0 mmol) in N,N-dimethylacetamide (150 ml), then a solution of 1-(2-chloroethyl)-pyrrolidine in toluene [prepared from commercially available 1-(2-chloroethyl)-pyrrolidine hydrochloride (16.1 g, 94.5 mmol) by partitioning between toluene (70 ml) and 1 M aq. sodium hydroxide solution (70 ml) and drying of the organic layer with Na2SO4] was added dropwise. The reaction mixture was stirred at room temperature for 16 h, then heated at 75° C. for 80 min. After cooling, the reaction mixture was partitioned between diethyl ether amid sat. aq. sodium hydrogencarbonate solution. The organic layer was dried (Na2SO4) and evaporated. Crystallization of the residue from diethyl ether afforded the title compound (3.74 g, 42%). White solid, MS (ISP)=298.2 (M+H)+.

Provenance & Evidence