反应详情

A mixture of 2,4-difluorobenzaldehyde (3.0 g, 21.1 mmol) and t-butyl piperazine-1-carboxylate (4.3 g, 23.1 mmol) in 30 mL of dry DCM is stirred for 2 h at RT, and NaHB(OAc)3 (6.7 g, 31.6 mmol) is added in portions with stirring. After the addition, the reaction mixture is stirred further overnight at RT. Water is added and the resulting mixture is extracted twice with DCM. The organic layer is dried over anhydrous MgSO4, filtered and concentrated in vacuo to obtain t-butyl 4-(2,4-difluorobenzyl)piperazine-1-carboxylate as a colorless oil: 1H NMR (CDCl3, 400 MHz) δ 1.46 (s, 9H), 2.40 (m, 4H), 3.42 (m, 4H), 3.54 (s, 2H), 6.78 (dt, 1H, J=10.0 Hz and 2.4 Hz), 6.85 (dt, 1H, J=8.4 Hz and 2.4 Hz), 7.33 (dd, 1H, J=15.2 Hz and 8.0 Hz).

1. stirringwith stirring
2. additionAfter the addition
3. stirringthe reaction mixture is stirred further overnight at RT
4. extractionthe resulting mixture is extracted twice with DCM
5. dry with materialThe organic layer is dried over anhydrous MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo