反应详情

The nitrating mixture (HNO3 d=1.42, 2 mL; concentrated H2SO4, 6 mL) was slowly added with stirring, at −5° to −10° C., to 4-Bromothiophene-2-carboxylic acid methyl ester (3 g, 13.57 mmol) dissolved in concentrated H2SO4 (10 mL). After being kept at −5 to −10° C. for 30 min. the mixture was poured over crushed ice. The solid precipitate was separated by filtration and washed with water and dried over P2O5 to give 3.7 g of 4-bromo-5-nitrothiophene-2-carboxylic acid methyl ester as a tan solid, which was used in the next step without further purification.

1. additionthe mixture was poured
2. customover crushed ice
3. customThe solid precipitate was separated by filtration
4. washwashed with water
5. dry with materialdried over P2O5