Chloroacetone → 7-Chloro-3-methyl-1-benzothiophene

Participants

Reaction Steps

A mixture of 2-chlorothiophenol (750 μL, 6.6 mmol), chloroacetone (1.1 mL, 13.8 mmol) and K2CO3 (1.8 g, 13 mmol) in acetone (15 mL) was refluxed for 2 h. The mixture was filtered and the solvent evaporated. The crude product was dissolved in chlorobenzene (30 mL) and polyphosphoric acid (PPA, 0.5 g) was added. The resulting mixture was refluxed over night (Plé et al., (1988) J. Heterocyclic Chem. 25, 1271-1272). Additional PPA (0.5 g) was added and the reaction mixture was refluxed for another 7 h. The solvent was decanted from the PPA-residue, the residue was treated with CH2Cl2 and the combined organic extracts were washed with water and dried, and then the solvents were removed by evaporation. The crude product was purified on silica using heptane as eluent, to give the title compound (770 mg, 64% over two steps). 1H NMR (400 MHz, CDCl3) δ ppm 2.44 (d, J=1.20 Hz, 3 H) 7.14 (q, J=1.20 Hz, 1 H) 7.32-7.38 (m, 2 H) 7.60-7.65 (m, 1 H)

Provenance & Evidence