Diisopropylamine → 2-Bromo-7-chlorothieno[3,2-b]pyridine

Participants

Reaction Conditions

Reaction Steps

A solution of 90 mL of tetrahydrofuran and diisopropylamine (4.6 mL, 32.9 mmol) were cooled to −78° C. and n-butyllithium (12.2 mL, 30.3 mmol) in hexane was added dropwise. The solution was heated to 0 ° C. for 10 minutes, recooled to −78° C., and 7-chloro-thieno[3,2-b]pyridine (4.29 g, 25.2 mmol) was added. The anion was stirred 10 minutes and 1,2-dibromo-1,1,2,2-tetrafluoroethane (3.3 mL, 27.8 mmol) was added. The solution was stirred an additional 20 minutes then allowed to warm to room temperature. After 1 hour the reaction mixture was poured into water and extracted with chloroform (3×100 mL). The combined organic portions were dried over magnesium sulfate, filtered, and dried to afford 4.65 g (74%) of 2-bromo-7-chloro-thieno[3,2-b]pyridine. 1H NMR (400 MHz, DMSO) d 8.64 (d, 1H), 7.91 (s, 1H), 7.65 (d, 1H); LC-MS: 250 (MH+); HPLC RT: 5.49.

Provenance & Evidence