反应详情

温度

-20 °C

To a flask was added MTBE (2 L) and ammonium chloride (60 g, 1.13 mol). The reaction was cooled to −20° C. Then concentrated aq ammonium hydroxide (160 mL) was added to the reaction followed by slow addition of commercial-grade sodium hypochlorite solution (149 g, 1.5 L). After addition, the reaction was stirred at −20° C. for additional 30 minutes. The MTBE layer was separated and washed with brine and dried over Na2SO4. In a separate flask under nitrogen was added diethyl 1H-pyrrole-2,4-dicarboxylate (40 g, 190 mmol) and dry DMF (400 mL). The reaction was cooled to 0° C. whereupon sodium hydroxide (190 mmol) was added portionwise to the reaction. The reaction was stirred at 0° C. for additional 1 hour before it was cooled to −20° C. At this time, the previously prepared MTBE solution of chloramine was added slowly to the reaction and the reaction was stirred at −20° C. for 1 hour. The reaction was quenched with saturated sodium hyposulfite solution. The organic layer of the reaction was separated and washed with water and brine, dried over sodium sulfate, filtered and concentrated to yield 40 g (95%) of the title compound. 1H NMR (400 MHz, CDCl3) δ ppm: 7.48 (1H, d, J=1.6 Hz), 7.24 (1H, d, J=1.6 Hz), 5.65 (2H, s), 4.32-4.23 (4H, merging quartets), 1.367-1.32 (6H, merging triplets). LCMS (condition A) m/z=227.2+ve.

1. additionAfter addition
2. customThe MTBE layer was separated
3. washwashed with brine
4. dry with materialdried over Na2SO4
5. additionwas added portionwise to the reaction
6. stirringThe reaction was stirred at 0° C. for additional 1 hour before it
7. temperaturewas cooled to −20° C
8. stirringthe reaction was stirred at −20° C. for 1 hour
9. customThe reaction was quenched with saturated sodium hyposulfite solution
10. customThe organic layer of the reaction was separated
11. washwashed with water and brine
12. dry with materialdried over sodium sulfate
13. filtrationfiltered
14. concentrationconcentrated