(2-Chlorophenyl)(2,2-diethoxyethyl)sulfane → 7-Chloro-1-benzothiophene
Reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[S:8][CH2:9][CH:10](OCC)OCC>C1(C)C=CC=CC=1>[Cl:1][C:2]1[C:3]2[S:8][CH:9]=[CH:10][C:4]=2[CH:5]=[CH:6][CH:7]=1Participants
3
Reactant 1
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 1-chloro-2-(2,2-diethoxyethylsulfanyl)benzene (3.95 g, 15.14 mmol) in toluene (40 mL) was added polyphosphoric acid (15 g, 137.5 mmol). The mixture was heated at reflux for 4 h. then was poured in to ice water, stirred for 30 min and extracted with toluene. The combined toluene extracts were washed with aqueous sodium bicarbonate followed by brine, dried over anhydrous sodium sulfate and evaporated under reduced pressure to yield the crude product. This material was purified by chromatography over silica gel eluting with hexane to afford pure 7-chlorobenzo[b]thiophene (1.72 g, 67.5%). 1H NMR (400 MHz, CDCl3) δ=7.13-7.30 (m, 3H), 7.38 (d, J=5.31 Hz, 1H), 7.62 (dd, J=7.33, 1.52 Hz, 1H); MS (ES+): m/z 169.06 [MH+].