1,1-Dimethylethyl (2S)-4-{[4-(acetylamino)-2-methylphenyl]methyl}-2-methyl-1-piperazinecarboxylate → tert-butyl (2S)-4-[(4-amino-2-methylphenyl)methyl]-2-methylpiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

1,1-Dimethylethyl (2S)-4-{[4-(acetylamino)-2-methylphenyl]methyl}-2-methyl-1-piperazinecarboxylate (D79) (497 mg, 1.4 mmol) in KOH (1M aq soln., 5 mL) and methanol (5 mL) was heated to 140° C. for 1 h in a microwave reactor. The reaction mixture was diluted with methanol (5 mL) and heated for a total of 4 h 55 minutes at 130° C. in the microwave. The reaction mixture was concentrated to remove the methanol and partitioned between DCM and water. The organic layer was dried and concentrated to give the crude product which was purified by chromatography. Elution with 0-100% diethyl ether/petroleum ether followed by a column flush with 10% (2M NH3 in methanol) in DCM yielded the title compound as a yellow oil (223 mg). δH (CDCl3, 400 MHz) 6.97 (1H, d), 6.52 (1H, d), 6.46 (1H, dd), 4.17 (1H, br.s), 3.76 (1H, d), 3.57 (2H, br.s), 3.29 (2H, m), 3.01 (1H, td), 2.70 (1H, d), 2.56 (1H, d), 2.30 (3H, s), 2.10 (1H, dd), 1.90 (1H, m), 1.45 (9H, s), 1.18 (3H, d). MS (AP+): MNa+ 342.3 (MNa+), no molecular ion (MH+) observed.

Provenance & Evidence