Dimethylformamide → HCID 71248772, compound

Participants

Reaction Conditions

Reaction Steps

(S)-ethyl 6-bromo-2-isopropyl-8-methoxy-4-methyl-1-oxo-1,2,3,4-tetrahydro-pyrrolo[1,2-a]pyrazine-7-carboxylate (1.2 mol) and Cu(I)CN (2.4 mol) were dissolved in dimethylformamide (DMF; 2.2 l) at 20° C. under N2. The mixture was stirred for 2 h at 110° C. Concentrated NH3.H2O (650 ml) was added at 60° C. The mixture was stirred for 30 min at 60° C. and then cooled to 20° C. The mixture was filtered off. Ethyl acetate (3000 ml) and H2O (2000 ml) were added and the organic layer was separated. The aqueous layer was extracted with ethyl acetate (3×1000 ml). The combined organic layers were washed with brine, dried and concentrated in vacuo. The crude product and a small batch of an earlier preparation were combined and washed with methyl tert-butyl ether to give a solid. Yield: 350 g of Intermediate I-3 (95% purity, 80% yield total).

Provenance & Evidence