反应详情

A mixture of methyl 3-amino-5-bromothiophene-2-carboxylate (15 g) produced in Example 1, step C, chloroacetonitrile (12 mL) and 4M hydrochloric acid/cyclopentylmethylether solution (100 mL) was stirred at room temperature for 2 hr, and stirred at 70° C. for 1 hr. The reaction system was concentrated under reduced pressure, and saturated aqueous sodium hydrogen carbonate was added to the residue. The precipitate was collected by filtration and washed with water. The obtained solid was dried at 80° C. for 8 hr under reduced pressure to give the title compound (18 g) as a pale-brown solid.

1. stirringstirred at 70° C. for 1 hr
2. concentrationThe reaction system was concentrated under reduced pressure, and saturated aqueous sodium hydrogen carbonate
3. additionwas added to the residue
4. filtrationThe precipitate was collected by filtration
5. washwashed with water
6. customThe obtained solid was dried at 80° C. for 8 hr under reduced pressure