Water → 1-(3-Methylbutyl)-4-(4-methylphenyl)-1H-pyrazole

Beteiligte Stoffe

Reaktionsschritte

To a solution of p-bromotoluene (0.66 g, 3.86 mmol) in tetrahydrofuran (20 ml) was added a solution of 1-(3-methylbutyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.41 g, 1.55 mmol) in tetrahydrofuran (10 ml), potassium carbonate (0.42 g, 3.0 mmol), [1,1-bis(diphenylphosphino)ferrocene]dichloropalladium (II) (40 mg, 0.077 mmol) and water (40 μl) and the mixture refluxed under nitrogen for 43 h. Water (50 ml) was added to the reaction mixture and stirring continued at RT for 10 min followed by extraction with ether (2×50 ml). The ether extract was then dried (MgSO4) and evaporated to give a brown oil (0.56 g) that solidified on standing. Purification by column chromatography (silica gel, 100% chloroform) afforded 1-(3-methylbutyl)-4-(4-methylphenyl)-1H-pyrazole (13) as a waxy pale yellow solid (0.216 g, 53%). 1H nmr (CDCl3, 300 MHz) 0.97, d (6.3 Hz), 2×Me; 1.62, m, H3″; 1.80, dt (7.3 Hz), H2″; 2.35, s, 4′-Me; 4.16, t (7.5 Hz), H1″; 7.16, d (8.1 Hz), H3′,5′; 7.37, d (8.1 Hz), H2′,6′; 7.59, s, H3 or H5; 7.74, s, H5 or H3. ESI (+ve) MS m/z 229 (M+H, 100%).

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