N-bromobutanimide → HCID 68153680, compound

Participants

Reaction Conditions

Reaction Steps

To benzyl 2-methylspiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (3.00 g, 8.84 mmol) in CH2Cl2 (30 mL) at 0° C. was added NBS (1.57 g, 8.84 mmol) portionwise. The reaction mixture was stirred at 0° C. for 2 h. Additional NBS (157 mg) was added and the reaction mixture was stirred at 0° C. for 15 minutes (repeated 6 additional times until starting material was consumed). The reaction mixture was diluted with 0.5 M Na2S2O3 (30 mL) and the aqueous phase was removed. The organic phase was washed with brine (30 mL). The organic layer was dried over sodium sulfate, filtered and the solvent was evaporated under reduced pressure. The crude product was purified by column chromatography utilizing a gradient of 0-30% ethyl acetate in CH2Cl2 to yield benzyl 6-bromo-2-methyl-spiro[3,4-dihydropyrrolo[1,2-a]pyrazine-1,4′-piperidine]-1′-carboxylate (2.34 g, 63%) as a cream solid. ESI-MS m/z calc. 417.1, found 418.1 (M+1)+; Retention time: 1.49 minutes (3 min run). 1H NMR (400 MHz, DMSO) δ 7.43-7.26 (m, 5H), 6.09 (d, J=3.7 Hz, 1H), 5.99 (d, J=3.7 Hz, 1H), 5.08 (s, 2H), 3.89-3.74 (m, 2H), 3.68 (t, J=5.8 Hz, 2H), 3.27 (t, J=5.8 Hz, 2H), 3.22-2.99 (m, 2H), 2.21 (s, 3H), 2.09-1.94 (m, 2H), 1.73-1.52 (m, 2H).

Provenance & Evidence