An Efficient Synthesis of 2,3-Dihydro-2-phenyl-4-quinolones from 2'-Aminoacetophenones

Abstract

2,아미노아세토폐논9로부터 2,3다이하이드로-2페닐*4퀴놀론의 효과적 합성 107 fied by silica gel column chromatography using 20% EtOAc/n-hexane as an eluant to give 3a (840.0 mg, 94%).M.p, 70-71 °C (lit2c 71-72 °C); 'HNMR (300 MHz, CDC13) 5 7.86 (dd, /=8.3 Hz, *=1.5 Hz, 1H), 7.74 (d) >15.6 Hz, 1H), 7.61 (d, >15.6 Hz, 1H), 2H), 3H), 1H), 2H), 6.33 (s, 2H); FT-IR (KBr) 3462 & 3334 (NH2), 3021, 1645 (C=O), 1614, 1575, 1448, 1212, 1012, 746, 696 cm上 Ms m/z (%) 223 (M+, 34), 222 (51), 146 (100), 120 (9), 103 (11), 77 (11).Preparation of (4a)〈typical procedure〉.A solution of 3a (670.0 mg, 3.0 mmol) and zinc chloride (IM in E^O, 3.3 mL, 3.3 mmol) in acetonitrile (10 mL) was heated to 80 °C for 24 h.After evaporation of acetonitrile, the mix ture was poured into sat.NH4C1 (30 mL) and the aqueous phase was extracted with methylene chlo ride (3x20 mL).The combined organic phases were dried over MgSO4, filtered, and evaporated to dry ness in vacuo.The residue was recrystallized from 90% n-hexane/EtOAc to give 4a (624.1 mg, 93%) as a pale yellow solid.M.p. 150-151 °C (lit.5 148-150 °C); >H NMR (300 MHz, CDC13) 8 7.87 (dd, /=7.9 Hz,也=1.5 Hz, 1H), 7.32-7.48(m, 6H), 6.75-6.81(m, 1H), 6.69 (d, >8.3 Hz, 1H), 4.76 (dd, J,=13.4Hz,仏=4.1 Hz, 1H), 4.51 (s, 1H), 2.90 (dd, /=16.2Hz,妇3.4Hz, 1H), 2.78 (dd,』=16.2Hz, W=W.l Hz, 1H); ,3C NMR (75 MHz, CDC13) 5 193.7, 151.9,141.4,135.8,