C,,ONE C2H<B (2)CH3COCH2COOC2H5 一CH3 COCHCOOC2Hs CaSonA CH3 COCHCOOC2Hs b CHiCoCCOOC?H CH31 CH 3 5% NaOH CH:COCHCOOC 2H 5 CH:COCHCH,CH HBr C2HSOH cHsBr CHIOH CH31 ()CH, COOCaHs C2HsONa CH2CH2Br CHiCocHCooCH CH3COCHCOOC2H5 C2H5 CrH ChSONa CH3 COCooN、 CH3CH2Br CH,COCcooC,Hs 40% NaoH. C C?Hs HBr CH3CH,OH CH3CH,Br