Dimethyl Sulfoxide → 2-Bromo-5-chlorothiophene-3-carbaldehyde

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Reaction Steps

To a solution of DMSO (2.10 mL, 29.7 mmol) in dichloromethane (50 mL) at −78° C. was added oxalyl chloride (1.90 mL, 26.8 mmol) dropwise and the mixture was stirred for 30 min. at the temperature. To it was then added (2-bromo-5-chloro-3-thienyl)methanol from Example 1, Step 2 (4.50 g, 19.8 mmol, crude) in dichloromethane (25 mL) via a cannula and the resultant solution was stirred for 30 min. Triethylamine (6.40 mL, 45.5 mmol) was added in one portion and the mixture was stirred at −78° C. for 30 min. and allowed to warm slowly in air. The mixture was concentrated in vacuo and then resuspended in ether and then filtered. The filtrate was concentrated in vacuo to give the desired product. The crude was used directly without further purification.

Provenance & Evidence