(I)R=C1,R’=H,加氯(金霉素) (II)R=H,R’=0H,加氧(土霉素) (II)R=R’=H(四环素) R HC OH R N(CH3) OH H H OH CONH OH O OH OR OH OH OH OH O O H3C R` N(CH3 )2 H H OH CONH2