Chloro-N,N-dimethylformiminium chloride → 2-Formyl-4,5,7,8-tetrahydro-thieno[2,3-d]azepine-6-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a stirred solution of 4,5,7,8-tetrahydro-thieno[2,3-d]azepine-6-carboxylic acid ethyl ester (1.50 g, 6.65 mmol) in 1,2-dichloroethane (20 ml) was added Vilsmeier reagent (1.49 g, 11.65 mmol). The reaction mixture was heated to 70° C. for 5 hours. The reaction mixture was allowed to cool to RT followed by addition of 1 M sodium acetate (20 ml). The mixture was vigorously stirred for 2 hours and then diluted with water (50 ml). The resulting solution was extracted with DCM (3×). The combined DCM extracts were washed with water, brine, and dried over MgSO4. The resulting mixture was filtered and solvent evaporated in vacuo to give the subtitled compound as a tan oil (1.56 g) that was used without further purification. MS: ESI (positive): 254 (M+H).

Provenance & Evidence