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Tetrahedron Letters
Volumn 54, Issue 15, 2013, Pages 1994-1997
N-arylation of heterocycles catalyzed by activated-copper in pure water
Author keywords

Activated copper; Aqueous medium; Heterocycle; Ullmann reaction
Indexed keywords

ACTIVATED COPPER; ANISOLE; COPPER; IODOBENZENE; UNCLASSIFIED DRUG;
EID: 84874946892     PISSN: 00404039     EISSN: 18733581     Source Type: Journal    
DOI: 10.1016/j.tetlet.2013.02.004     Document Type: Article
Times cited : (31)
References (69)
  • 68
    • 85030493954 scopus 로고    scopus 로고
    • Catalyst preparation. Activated copper powder was prepared by reduction reaction of CuSO4 and Zn in water under a violent stirring. Briefly, to a solution of CuSO4-5H2O (2.5 g, 10 mmol) in 50 mL of distilled water, 0.9 g (13 mmol) of Zn powder was added slowly at room temperature over a period of 10 min under a violent stir. During which a brownish red precipitate was formed. After the action mixture was kept stirring for 1 h, 5 mL (2 mol/L) HCl aqueous solution was added to get rid of the excessive Zn. After 30 min, the precipitate was separated by filter and washed with water (3 - 20 mL). The catalyst was then washed with ethanol and dried in a vacuum desiccator. 0.56 g of copper powder was obtained
    • Catalyst preparation. Activated copper powder was prepared by reduction reaction of CuSO4 and Zn in water under a violent stirring. Briefly, to a solution of CuSO4-5H2O (2.5 g, 10 mmol) in 50 mL of distilled water, 0.9 g (13 mmol) of Zn powder was added slowly at room temperature over a period of 10 min under a violent stir. During which a brownish red precipitate was formed. After the action mixture was kept stirring for 1 h, 5 mL (2 mol/L) HCl aqueous solution was added to get rid of the excessive Zn. After 30 min, the precipitate was separated by filter and washed with water (3 - 20 mL). The catalyst was then washed with ethanol and dried in a vacuum desiccator. 0.56 g of copper powder was obtained.
  • 69
    • 85030488608 scopus 로고    scopus 로고
    • General procedure: Iodobenzene (1.0 mmol), pyrazole (1.5 mmol), LiOH (2.0 mmol), TBAB (0.2 mmol), activated Cu (0.1 mmol), and 2 mL H2O were added to a 10 mL flask, then the flask was sealed by a condenser pipe with rubber diaphragm on the upper end. The mixture was heated in an oil bath at 120 -C for 24 h. After cooling the mixture to the room temperature, the product was extracted by ethyl acetate (3 - 10 mL). The combined extracts were washed by brine (15 mL), dried over anhydrous MgSO4, and evaporated under the reduced pressure. Further purification by silica gel column chromatography (5:1 petroleum ether/ethyl acetate) give 1-phenyl-1Hpyrazole (2a, 0.126 g, 88%) as a Colorless liquid. 1H NMR (400 MHz, CDCl3) d: 7.88 (d, J = 2.4 Hz, 1H), 7.70-7.65 (m, 3H), 7.45-7.30 (m, 2H), 7.25 (t, J = 7.5 Hz, 1H), 6.46-6.43 (m, 1H) ppm. 13C NMR (100 MHz, CDCl3) d: 139.5, 138.9, 128.8, 126.0, 125.9, 118.0, 106.8 ppm. MS (EI) m/z: 144 (100%), 117, 77 51
    • General procedure: Iodobenzene (1.0 mmol), pyrazole (1.5 mmol), LiOH (2.0 mmol), TBAB (0.2 mmol), activated Cu (0.1 mmol), and 2 mL H2O were added to a 10 mL flask, then the flask was sealed by a condenser pipe with rubber diaphragm on the upper end. The mixture was heated in an oil bath at 120 -C for 24 h. After cooling the mixture to the room temperature, the product was extracted by ethyl acetate (3 - 10 mL). The combined extracts were washed by brine (15 mL), dried over anhydrous MgSO4, and evaporated under the reduced pressure. Further purification by silica gel column chromatography (5:1 petroleum ether/ethyl acetate) give 1-phenyl-1Hpyrazole (2a, 0.126 g, 88%) as a Colorless liquid. 1H NMR (400 MHz, CDCl3) d: 7.88 (d, J = 2.4 Hz, 1H), 7.70-7.65 (m, 3H), 7.45-7.30 (m, 2H), 7.25 (t, J = 7.5 Hz, 1H), 6.46-6.43 (m, 1H) ppm. 13C NMR (100 MHz, CDCl3) d: 139.5, 138.9, 128.8, 126.0, 125.9, 118.0, 106.8 ppm. MS (EI) m/z: 144 (100%), 117, 77, 51.

* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.