反应详情

A mixture of 1-methylpiperazin-2-one (128 mg, 1.12 mmol), 3-oxoazetidine-1-carboxylic acid tert-butyl ester (231 mg, 1.35 mmol) and 4 Å powdered molecular sieves (150 mg) in DCE (4 mL) was stirred at room temperature for 1.5 h before the addition of sodium triacetoxyborohydride (475 mg, 2.24 mmol). The reaction mixture was filtered through celite, washing with DCM. The filtrate was concentrated in vacuo and the resulting residue was purified by column chromatography (Si—PCC, MeOH:EtOAc, 0-10%) affording 3-(4-Methyl-3-oxopiperazin-1-yl)azetidine-1-carboxylic acid tert-butyl ester as an oil (211 mg, 70%). 1H NMR (CDCl3, 300 MHz): δ 3.99-3.92 (m, 2 H); 3.81 (dd, J=8.8, 5.1 Hz, 2 H); 3.36 (t, J=5.5 Hz, 2 H); 3.20-3.14 (m, 1 H); 3.08 (t, J=5.5 Hz, 2 H); 2.97 (s, 3 H); 2.70-2.56 (m, 2 H); 1.44 (s, 9 H).

1. filtrationThe reaction mixture was filtered through celite
2. washwashing with DCM
3. concentrationThe filtrate was concentrated in vacuo
4. customthe resulting residue was purified by column chromatography (Si—PCC, MeOH:EtOAc, 0-10%)