78% |
With potassium carbonate In isopropyl alcohol for 20h; Heating; |
|
72% |
With potassium carbonate In dimethyl sulfoxide at 100℃; for 4h; Inert atmosphere; |
|
71% |
With potassium carbonate In N,N-dimethyl-formamide at 80℃; for 24h; |
|
71% |
With potassium carbonate In N,N-dimethyl-formamide; Petroleum ether |
5 2-(phenylsulfanyl)benzenecarbaldehyde
2-(phenylsulfanyl)benzenecarbaldehyde 2-fluoro-benzaldehyde (2.00 g, 16.1 mmol), potassium carbonate (2.45 g, 17.7 mmol) and thiophenol (17.1 mmol) were dissolved in 10.0 mL DMF in a 50 mL round-bottomed flask under dry nitrogen, topped with a reflux condenser. The reaction mixture was heated to 80° C. for 24 hrs. After cooling, the mixture was added to 50 mL of saturated potassium carbonate solution and extracted with 3*50 mL portions of ether. The extracts were dried with magnesium sulfate and evaporated. The crude product was further purified by chromatography on silica gel using 9:1 petroleum ether 60-80 and dichloromethane as eluent to give a yellow oil (2.46 g, 71%). 1 NMR (200 MHz, CDCl3): δ 7.07 (dd, J1=7.8, J2=1.2, 1H), 7.27-7.45 (m, 7H), 7.87 (dd, J1=7.3, J2=2.0, 1H), 10.37 (s, 1H) ppm. |
71% |
With potassium carbonate In N,N-dimethyl-formamide at 80℃; for 24h; Inert atmosphere; |
5 2-(phenylsulfanyl)benzenecarbaldehyde
2-fluoro-benzaldehyde (2.00 g, 16.1 mmol), potassium carbonate (2.45 g, 17.7 mmol) and thiophenol (17.1 mmol) were dissolved in 10.0 mL DMF in a 50 mL round-bottomed flask under dry nitrogen, topped with a reflux condenser. The reaction mixture was heated to 80° C. for 24 hrs. After cooling, the mixture was added to 50 mL of saturated potassium carbonate solution and extracted with 3*50 mL portions of ether. The extracts were dried with magnesium sulfate and evaporated. The crude product was further purified by chromatography on silica gel using 9:1 petroleum ether 60-80 and dichloromethane as eluent to give a yellow oil (2.46 g, 71%). 1H NMR (200 MHz, CDCl3): δ 7.07 (dd, J1=7.8, J2=1.2, 1H), 7.27-7.45 (m, 7H), 7.87 (dd, J1=7.3, J2=2.0, 1H), 10.37 (s, 1H) ppm. |
14% |
With magnesium methanolate In N,N-dimethyl-formamide at 80℃; for 12h; |
|
|
With potassium carbonate In isopropyl alcohol |
|
|
With potassium carbonate In acetonitrile Heating; |
|
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With potassium carbonate In isopropyl alcohol Heating / reflux; |
A mixture of 2-fluorobenzaldehyde (2.48 g, 20 mmol), thiophenol (2.42 g, 22 mmol) and potassium carbonate (3.04 g, 22 mmol) were mixed together in 2-propanol (10 mL) and reflux ed overnight. The reaction was cooled, added to 50 mL of water, and extracted with DCM (2 X 30 mL). Organic layer was washed with 5 N KOH, brine, dried over anhydrous Na2SO4 and solvent evaporated to obtain 4.24 g of 2-(phenylthio)benzaldehyde. 1H NMR(400 MHz, CDCl3) δ: 10.38(s, IH), 7.89-7.87(m, IH), 7.45-7.33(m, 7H), 7.1-7.08(m, IH). |
|
With potassium carbonate In dimethyl sulfoxide at 100℃; for 4h; |
1 2-(Phenylthio)benzaldehyde
2-Fluorobenzaldehyde (9 ml, 90 mmol) and benzenethiol (8.8 ml, 90 mmol) were dissolved in 30 ml dimethylsulfoxide. Potassium carbonate (26 g, 190 mmol) was added and the mixture was heated at 100ºC for 4 h. The mixture was allowed to cool and was poured into water. The aqueous layer was extracted with ethyl acetate. The combined organics were washed with water and brine and were dried over sodium sulphate. Filtration and evaporation give 18.5 g (78.3 mmol, 92%) of the title compound as a yellow oil. Used as such without further purification. Purity 91%. 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.08 - 7.12 (m, 1 H), 7.29 - 7.46 (m, 7 H), 7.88 (dd, J=7.42, 1.56 Hz, 1 H), 10.40 (s, 1 H). HPLC/MS (9 min) retention time 6.53 min. LRMS: m/z 215 (M+1). |
|
With potassium carbonate In dimethyl sulfoxide at 100℃; for 4h; |
1 6.1 2-(Phenylthio)benzaldehyde (7a)
2-Fluorobenzaldehyde (9 ml, 90 mmol) and benzenethiol (8.8 ml, 90 mmol) were dissolved in 30 ml dimethylsulfoxide. Potassium carbonate (26 g, 190 mmol) was added and the mixture was heated at 100 °C for 4 h. The mixture was allowed to cool and was poured into water. The aqueous layer was extracted with ethyl acetate. The combined organics were washed with water and brine and were dried over sodium sulphate. Filtration and evaporation gave 7a (18.5 g, 78.3 mmol, 92% yield) as a yellow oil. Used as such without further purification. Purity 91%. 1H NMR (400 MHz, CDCl3) δ ppm 7.08-7.12 (m, 1H, Ar), 7.29-7.46 (m, 7H, Ar), 7.88 (dd, J = 1.4, 1.6 Hz, 1H, PhCHO H-6), 10.40 (s, 1H, CHO). HPLC/MS (9 min) retention time 6.53 min. LRMS: m/z 215 (M+1). |
|
With potassium carbonate In N,N-dimethyl-formamide at 180℃; for 2h; Inert atmosphere; |
3. General procedure for reduction of the coupling reaction
General procedure: To a solution of DMF (10 mL) containing 2- fluorobenzaldehyde (5.0 mmol) and thiophenol (5.0 mmol) was added K 2 CO 3 (5.0 mmol) and the reaction mixture was stirred for 2 hours at 180 0 C under an nitrogen atmosphere. It was cooled to room temperature and after usual workup and concentration, the product was purified over silica gel. Thus, 2- thioetherbenzaldehydes were prepared in good yields with 95-100% |
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With potassium carbonate In dimethyl sulfoxide at 100℃; for 4h; |
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