反应详情

A solution of 6-methoxy-3-pyridine carboxaldehyde (100 mg, 0.73 mmol) in ethanol (2 mL) and acetic acid (0.2 mL) at room temperature was treated with tert-butyl-1-piperazine carboxylate (2.5 eq, 1.82 mmol, 339 mg) and stirred for 5 minutes. Sodium cyanoborohydride (0.95 eq, 0.69 mmol, 44 mg) was added portionwise and the reaction then stirred for 16 h. Concentration in vacuo and preparative tlc purification (EtOAc) gave the product (168 mg, 75%) as a colourless oil; δH (500 MHz, CDCl3) 1.47 (s, 9H, C(CH3)3), 2.00 (s, br, 2H, piperazine NCH2), 2.39 (t, J=4.7 Hz, 2H, piperazine NCH2), 3.43 (t, J=4.9 Hz, 4H, piperazine N(CH2)2), 3.45 (s, 2H, CH2), 3.94 (s, 3H, OCH3), 6.73 (d, J=8.4 Hz, 1H, methoxypyridine H-5), 7.57 (dd, J=8.5, 2.4 Hz, 1H, methoxypyridine H-4), 8.05 (d, br, J=2.3 Hz, 1H, methoxypyridine H-2);

1. customthe reaction
2. stirringthen stirred for 16 h
3. concentrationConcentration
4. customin vacuo and preparative tlc purification (EtOAc)