反应详情

温度

50 °C

to a nitrogen purged 2-L round bottom flask equipped with a mechanical stirrer, upright condenser, and thermometer was charged 1-(4-chlorobenzyl)-3-hydroxypyridin-2(1H)-one (1) (50.0 g, 0.21 mol, 1 equiv.), tert-butyl piperazine-1-carboxylate, (2) (79.0 g, 0.42 mol, 2 equiv.) [CAS No. 57260-71-6] and ethanol (750 mL, 15 parts v/w). The solution was stirred and 37% aqueous formaldehyde (34.7 mL, 0.47 mol, 2.2 equiv.) and acetic acid (36.4 mL, 0.64 mol, 3 equiv.) were added and the solution stirred for 1 hour after which the reaction solution was heated to 50° C. for 18 hours. The reaction mixture was then cooled below room temperature and filtered under vacuum. The resulting solid was rinsed with ethanol (250 mL) and dried under a stream of nitrogen to afford 77.2 g (83.9%) of the desired product. 1H NMR (DMSO-d6) δ ppm 7.4 (d, 2H), 7.3 (d, 2H), 7.2 (d, 1H), 6.2 (d, 1H), 5.1 (s, 2H), 3.4-3.2 (m partly under brs water peak, 6H), 2.3 (m, 4H), 1.4 (s, 9H).13C NMR (DMSO-d6) [observed] δ ppm 157.24, 153.77, 144.36, 136.33, 132.15, 129.67, 128.48, 126.86, 124.56, 107.01, 78.74, 54.68, 52.49, 50.64, 43.48, and 28.03.

1. customto a nitrogen purged 2-L round bottom flask
2. customequipped with a mechanical stirrer
3. stirringthe solution stirred for 1 hour after which the reaction solution
4. temperatureThe reaction mixture was then cooled below room temperature
5. filtrationfiltered under vacuum
6. washThe resulting solid was rinsed with ethanol (250 mL)
7. customdried under a stream of nitrogen