反应详情

To an ice-cooled suspension of 2-methoxy-4-nitro-benzoic acid (5.915 g, 30 mmol) in acetonitrile (50 ml) and CH2Cl2 (40 ml) under N2-atmosphere, TPTU (8.912 g, 30 mmol) and NEt3 (8.36 ml, 60 mmol) is added. After stirring for 40 min, piperidine (3.26 ml, 33 mmol) is added and the reaction mixture is slowly warmed up to rt. After 16 h, AcOEt (0.5 L), water (0.4 L) and saturated NaHCO3 solution (0.2 L) is added, the aqueous phase separated off and extracted 3× with AcOEt. The organic layers are washed with 10% citric acid solution, water and brine, dried (Na2SO4) and concentrated. Crystallization from AcOEt/hexane yields the title compound: m.p.: 104° C.; 1H-NMR (DMSO-d6): 7.88 (dd, 1H), 7.84 (d, 1H), 7.47 (d, 1H), 3.93 (s, H3C), 3.7-3.5 (m, 2H), 3.07 (m, 2H), 1.64-1.5 (m, 4H), 1.42 (m, 2H).

1. waitAfter 16 h
2. customthe aqueous phase separated off
3. extractionextracted 3× with AcOEt
4. washThe organic layers are washed with 10% citric acid solution, water and brine
5. dry with materialdried (Na2SO4)
6. concentrationconcentrated
7. customCrystallization from AcOEt/hexane