7-Methylquinoline → 7-Methyl-2-phenylquinoline

Beteiligte Stoffe

Reaktionsschritte

To a solution of 7-methylquinoline (1.63 g, 11.4 mmol) in dry THF (10mL), cooled by ice/water, is added phenyllithium (1.9M in cyclohexane/ether 70/30, 6.0 mL, 11.4 mmol) dropwise over 5 min. After 15 min, the cooling bath is removed, and the solution is stirred at rt for 5 h. The reaction is quenched by adding MeOH, and stirring is continued overnight. Water is added, the mixture is extracted with EtOAc (3×35 mL), and the combined extracts are dried over MgSO4. The drying agent is filtered off, and air is bubbled into the solution for 7 d. The solvent is evaporated; the residue is dissolved in warm (≈50° C.) EtOAc/hexanes and filtered warm. The filtrate is concentrated and dried in vacuo to obtain the crude title compound that is used directly for the next step. Further purification is possible by chromatography on silica gel (Jones Flashmaster, eluting with hexanes:EtOAc 3:1→2:1→1:1). 1H NMR (CDCl3, 400 MHz) δ 2.58 (s, 3H), 7.31 (d, J=3.7 Hz, 1H), 7.36-7.49 (m, 1H), 7.52 (t, J=8.0 Hz, 2H), 7.72 (d, J=8.2 Hz, 1H), 7.82 (d, J=8.2 Hz, 1H), 7.96 (s, 1H), 8.16 (t, J=8.0 Hz, 2H). MS (ES+): m/z 220.3 (100) [MH+]. HPLC: tR=2.7 min (Platform II, nonpolar—5 min).

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