反应详情

The crude product 2-(3-nitro-2-oxopyridin-1(2H)-yl)acetic acid (˜14.7 mmol), 4.71 g (14.7 mmol) of TBTU, 1.98 g (14.7 mmol) of HOBT and 4.99 mL (29.3 mmol, 2 eq) of DIPEA are dissolved in 60 mL of DMF (argon atmosphere). 1.97 mL (14.7 mmol) of 2-ethyl-butylamine ((→pH=6) and another eq DIPEA (→pH=8) are added. After 1 h a half eq DIPEA is further titrated and stirred overnight at RT. If the TLC control shows incomplete conversion, it is stirred for further 3 h at 45° C. The solvent is removed in vacuo and the residue is taken up in 500 mL of DCM/MeOH (8/2). It is subsequently washed with 10% citric acid (3×100 mL), saturated NaHCO3 solution (3×100 mL) and brine (75 mL). The organic phase is dried over sodium sulfate and the solvent is removed in vacuo. The crude product (3.5 g) is treated with 10 mL of ethyl acetate, 30 mL of PE (40-60) is added and stirred for 15 min at RT. The solid is filtered off, washed with some amount of PE and dried.

1. stirringis stirred for further 3 h at 45° C
2. customThe solvent is removed in vacuo
3. washIt is subsequently washed with 10% citric acid (3×100 mL), saturated NaHCO3 solution (3×100 mL) and brine (75 mL)
4. dry with materialThe organic phase is dried over sodium sulfate
5. customthe solvent is removed in vacuo
6. additionThe crude product (3.5 g) is treated with 10 mL of ethyl acetate, 30 mL of PE (40-60)
7. additionis added
8. stirringstirred for 15 min at RT
9. filtrationThe solid is filtered off
10. washwashed with some amount of PE
11. customdried