Diisopropylamine → Methyl 1-methyl-2-oxopyrrolidine-3-carboxylate

Participants

Reaction Steps

To a solution of diisopropylamine (11.3 g, 0.11 mol) in THF (150 ml), at -78° was added n-butyl lithium (60 mls of a 1.6M solution in hexane). The solution was stirred for 0.5 hours before adding N-methyl-2-pyrrolidone (10.1 g; 0.1 mol) in THF (50 ml) over a period of 5 minutes. After 0.75 hours. a solution of dimethylcarbonate (10.8 g: 0.12 mols) in THF (30 ml) was added and the reaction mixture allowed to warm to room temperature overnight. The reaction mixture was poured into water (50 ml) and extracted with dichloromethane (3×150 ml). The combined extracts were dried (Na2SO4) and evaporated in vacuo. The crude product was chromatographed on silica gel using ethyl acetate/methanol (2:1) as eluant to afford the title product as a clear liquid (4 g). δ(CDCl3) 1.90-2.70 (2H, m, CH2); 2.80 (3H, s, CH3) 3.20-3.60 (3H, m, CH and CH2); 3.70 (3H, s, CO2CH3).

Provenance & Evidence