Formaldehyde → tert-Butyl 3-[(4-benzyl-1,4-diazepan-1-yl)carbonyl]-4-methylpiperazine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

(S)-4-Boc-2-piperazinecarboxylic acid (530 mg, 2.17 mmol) was dissolved in MeOH (25 mL) and formaldehyde (1.76 mL, 37 wt % in water, 21.7 mmol) was added. The reaction mixture was stirred for 30 min, NaBH(OAc)3 (0.92 g, 4.34 mmol) was added and the reaction mixture was stirred for 2 h. The solvents were removed in vacuo and the residue was purified by reverse phase column chromatography. The residue and benzyl homopiperazine (0.41 g, 2.17 mmol) were dissolved in DMF (20 mL) and cooled to 0° C. DIPEA (0.59 g, 4.56 mmol) and HBTU (0.82 g, 2.17 mmol) were added and the reaction mixture was stirred for 3 h. The solvents were removed in vacuo and the residue was partitioned between DCM (100 mL) and water (50 mL). The organic fraction was washed with 1M aq Na2CO3 (25 mL), brine (25 mL), dried (MgSO4) and concentrated in vacuo. The residue was purified by reverse phase column chromatography to give the title compound (0.64 g, 71%) as a light yellow gum. LCMS (ES+): 417.4 [MH]+.

Provenance & Evidence