Hydrochloric Acid → 2-Chloro-5-methylthiophene-3-carboxylic acid

Temperature

-78 °C

5-Bromo-2-chloro-3-thiophenecarboxylic acid (2.41 g) was dissolved in tetrahydrofuran (50 ml), and the mixture was cooled to -78° C. N-Butyllithium (1.6M in hexane, 14 ml) was slowly added dropwise. The mixture was stirred at -78° C. for 1 hour, and iodomethane (1.4 ml) was added dropwise. The reaction mixture was warmed to room temperature, stirred at room temperature for 15 hours, poured into water, acidified with 1N hydrochloric acid and extracted with ethyl acetate. The extract was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give 2-chloro-5-methyl-3-thiophenecarboxylic acid (1.7 g) as crystals.

1. temperatureThe reaction mixture was warmed to room temperature
2. stirringstirred at room temperature for 15 hours
3. extractionextracted with ethyl acetate
4. dry with materialThe extract was dried over anhydrous magnesium sulfate
5. concentrationconcentrated under reduced pressure

ORD record

ord-a94d7433d0144ec7a67d5cd39b71e528

Source dataset

uspto-grants-1998_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05840917