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 and sat. aq. sodium hydrogen-carbonate 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