行十十十十十 ST A&F U acid halide acid anhydride ester 酰卤 酸酐 酯 酰胺 H 1 amide 2°amide 3°amide R C O X R C O O C O R R C O O R' acid halide acid anhydride ester R C O N H H R C O N R' H R C O N R' R" 1° amide 2° amide 3° amide 酰卤 酸酐 酯 酰胺