Tetrahydrofuran → Thieno(2,3-c)isoquinolin-5(4H)-one

Participants

Reaction Steps

0.08 ml of thionyl chloride were added to a solution of 3-phenylthiophen-2-carboxylic acid (6) (0.138 g, 0.68 mmol) in 2 ml of anhydrous benzene and the mixture was refluxed for 2 hrs. The solvent and the excess thionyl chloride were removed under vacuum and the residue was taken up using 3 ml of THF, and NaN3 (0.066 g, 1.02 mmol) in 1 ml of water was added rapidly to this stirred solution at 0° C. The mixture was left for 1 hr at room temperature with stirring, poured into 10 ml of crushed ice and water and extracted with ethyl ether (4×10 ml) and the separated organic layer was washed, dried and evaporated under vacuum. The residue was dissolved in 1 ml of o-dichlorobenzene and then added dropwise to 3 ml of boiling o-dichlorobenzene with stirring. The mixture was refluxed for 5 hrs, then cooled and evaporated. The mixture was subjected to flash chromatography, elution with 90:10 petroleum ether-ethyl acetate giving the end compound (7) (0.061 g, 0.3 mmol, 44% yield) as a pure solid (M. Pt. 266-268° C.); IR: 2849, 1647 cm−1 (NHCO).

Provenance & Evidence