(3)酯化 RCOOH+HSR→R一C-SR'+H,O (4)亲核取代 CH3CH2SH+CH3CH2—Br→CHCH2SCH2CH3+HBr (CH,CH22S+CH,CH2一Br→(CH,CH2)3$Br R _cI > SR'+ HCI CH;CH2SH+ SC2H5 CH3- CH3 SC2Hs (保护羰基，HP除去) rganiChem Organic Chem (3) 酯化 RCOOH + HSR' R C SR' O + H2 O （4）亲核取代 CH3 CH2 SH ＋ CH3 CH2 Br CH3 CH2 SCH2 CH3 ＋ HBr (CH3 CH2 ) 2 S ＋ CH3 CH2 Br (CH3 CH2 ) 3 SBr CH3 CH2 SH ＋ R' C O Cl R C O SR' ＋ HCl CH3 C O CH3 C SC2 H5 SC2 H5 CH3 CH3 (保护羰基，H2 /Pt除去）