Formaldehyde → 1,1-Dimethylethyl (2S)-2-methyl-4-{[4-(methylamino)phenyl]methyl}-1-piperazinecarboxylate

Participants

Reaction Steps

To 1,1-dimethylethyl (2S)-4-[(4-aminophenyl)methyl]-2-methyl-1-piperazinecarboxylate (D22) (4.14 g, 13.56 mmol) in dry MeOH (80 mL) at 50° C. under an argon atmosphere was added paraformaldehyde (1.22 g, 40.67 mmol) and sodium methoxide (3.65 g, 67.78 mmol). The mixture was stirred for ˜24 h then sodium borohydride (1.54 g, 40.67 mmol) was added portion-wise and the reaction stirred at 50° C. overnight. After cooling to room temperature, acetone (10 mL) was added and the solvent removed in vacuo. The residue was partitioned between DCM and water and the organic phase was washed with brine, then dried and concentrated. Column chromatography gave the title compound as a colourless, crystalline solid (3.73 g). δH (CDCl3, 400 MHz) 7.13 (2H, d), 6.57 (2H, d), 4.16 (1H, br.s), 3.78 (1H, d), 3.67 (1H, br.s), 3.42 (1H, d), 3.30 (1H, d), 3.08 (1H, td), 2.83 (3H, s), 2.75 (1H, m), 2.59 (1H, m), 2.06 (1H, dd), 1.94 (1H, m), 1.45 (9H, s), 1.21 (3H, d).

Provenance & Evidence