Dimethylformamide → 4-Oxo-4,5,7,8-tetrahydro-thieno[2,3-d]azepine-6-carboxylic acid ethyl ester

Participants

Reaction Steps

The product of step b) (˜165 mmol) was dissolved in 1 L of DCM. DMF (100 uL) was added followed slowly by oxalyl chloride (21.7 mL, 247 mmol). After 1 hour the reaction was concentrated to dryness and the crude material was re-dissolved in DCE (1 L). AlCl3 (55 g, 410 mmol) was carefully added and the reaction was stirred at room temperature for ½ hour. The crude reaction was quenched with ice, diluted with EtOH (300 mL), washed with water (3×), and dried over MgSO4. The title product was purified by silica gel chromatography (30% EtOAc in Hexanes) to give 10.5 g of the subtitle compound as an off-white solid. MS: ESI (positive): 240 (M+H).

Provenance & Evidence