50% |
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To an evacuated 1000 mL three necked round bottomed flask magnesium (1.2 g, 0.05 mol) and dry diethylether (15 mL) were placed. To the stirred mixture a 2.0 M solution of methyl iodide (7.1 g, 3.0 mL, 0.05 mol) in diethylether was added dropwise over 40 min. The resulting solution of methylmagnesium iodide was stirred at room temperature for 1 h. The solution of starting 4'-alkyloxy-4-carbonitrile 2a or 2b (9.1 g for 2a, 10.0 g for 2b, 0.0325 mol) in diethylether (400 mL) was added to a mixture of methylmagnesium iodide and heated at the boiling temperature of diethylether for 6 h, then the flask was cooled and distilled water (300 mL) was added slowly. The mixture was left to stir for an additional 30 min. The aqueous and etheric layers were separated, water phase was extracted with diethylether (2×250 mL). The combined organic phase was dried with MgSO4 and evaporated. The crude product was purified by column chromatography on silica gel eluting with dichloromethane.4.3.2. 1-(4'-Octyloxy-biphenyl-4-yl)-ethanone 3bYield: 50% (5.3 g), white crystals; mp=115-118 C; Rf (CH2Cl2) 0.70; deltaH (500 MHz CDCl3): 7.95 (d, J=8.4 Hz, 2H), 7.62-7.56 (m, 4H), 6.84 (d, J=8.4 Hz, 2H), 3.89 (t, J=6.4 Hz, 2H, CH2), 2.58 (s, 3H, COCH3), 1.72 (q, J=6.4 Hz, 2H, CH2), 1.30 (q, J=6.4 Hz, 2H, CH2), 1.27 (br s, 8H, 4× CH2), 0.84 (t, J=6.4 Hz, 3H, CH3); deltaC (125 MHz CDCl3): 196.9, 158.4, 146.0, 135.7, 131.9, 129.0, 128.6, 128.2, 127.4, 114.7, 70.2, 31.5, 30.4, 29.9, 26.6, 23.8, 22.4, 14.0; numax(KBr) 3099, 2943, 1715 (CO), 1607, 1454, 764, 632 cm-1; Anal. Calcd for C22H28O2 (324.46): C, 81.44; H, 8.70%. Found: C, 81.70; H, 8.92%. Mass (ESI) m/z (%) 324.60. |