反应详情

A solution of 20% lithiumhexamethyldisilazane in tetrahydrofuran (335 mL, 400 mmol), 2,4-dihydroxy acetophenone, 14 (15.2 g, 100 mmol) in tetrahydrofuran (150 mL) and ethyl-3,4-dimethoxy benzoate, 7 (21 g, 100 mmol) in tetrahydrofuran (100 mL) were reacted to afford 21, 1-(3,4-dimethoxy-phenyl)-3-(2,4-dihydroxy-phenyl)-propane-1,3-dione (37 g), which was cyclized with Dowex-H+ (15 g) in 2-propanol (250 mL) in a similar way as described for 22 to afford 27. Yield 15.4 g, (52%); mp 263-265° C.; MS (FAB) 299 (M++1); IR (KBr) 3452, 1625; 1H NMR (200 MHz, CDCl3+DMSO-d6) δ 9.83 (s, 1H), 7.32 (d, J=8.5 Hz, 1H), 6.97 (dd, J=8.5 Hz, 1.7 Hz, 1H), 6.83 (d, J=1.7 Hz, 1H), 6.43 (d, J=8.5 Hz, 1H), 6.34 (s, 1H), 6.30 (dd, J=9.7 Hz, 2.0 Hz, 1H), 6.08 (s, 1H), 3.35 (s, 3H), 3.32 (s, 3H).