Sulfuric Acid → 4,4-Diethyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene

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Reaction Steps

H2SO4 (7.0 mL) was added dropwise to 3-(2,2′-bithiophene-3-yl)pentan-3-ol (IIa) (2.67 g, 11 mmol) under stirring at room temperature. After stirring for 12 h, CH2Cl2 (100 mL) and water (100 mL) were added. The organic layer was separated and the aqueous layer was extracted with CH2Cl2. The combined organic extracts were successively washed with saturated NaHCO3 and brine. After drying over MgSO4, the solvent was removed in vacuo. The crude oil was purified with column chromatography (eluent hexane) to afford pure dark yellow oil (Ia) (1.2 g, 47%). 1H-NMR (CDCl3): δ=7.21 (d, J=4.8 Hz, 2H), 7.00 (d, J=4.8 Hz, 2H), 1.98 (q, J=6.8 Hz), 4H), 0.70 (t, J=7.0 Hz, 6H). 13C-NMR (CDCl3): δ=157.89, 137.36, 125.09, 122.16, 54.76, 30.71, 9.74.

Provenance & Evidence