Dimethyl Sulfoxide → 4-Boc-1-Cbz-piperazine-2-carbaldehyde

Participants

Reaction Conditions

Reaction Steps

To SO3-pyr complex (5.84 g, 36.69 mmol) was added pyridine (2.90 mL, 36.66 mmol) and DMSO (7.20 mL, 101.37 mmol). Slurry was stirred at room temperature 10 min before DCM (30 mL) was added and mixture was cooled to 0° C. Then solution of 1-benzyl 4-tert-butyl 2-(hydroxymethyl)piperazine-1,4-dicarboxylate (6.44 g, 18.37 mmol), Hunig's base (11.0 mL, 63.15 mmol) and DMSO (7.20 mL, 101.37 mmol) in DCM (70 mL) was added over 10 min. Reaction mixture was stirred at 0° C. 30 min and TLC showed complete consumption of starting material. Reaction was washed subsequently with H2O (50 mL), cold aqueous 1N HCl (until aqueous phase stayed acidic), then NaHCO3 (aqueous saturated, 50 mL) and finally NaCl (aqueous saturated, 50 mL). Organic phase was dried over Na2SO4 and solvent concentrated. Crude 1-benzyl 4-tert-butyl 2-formylpiperazine-1,4-dicarboxylate (˜6.40 g, quant) was obtained as colorless oil and was taken directly into the next step.

Provenance & Evidence