CHO H- OH HH OHH CH,OH HO--H OH HOCH2 CHO CHO H H-OH OHOH H OH OH 2 CH,OH OH H,OH CH,OH CH,OH O、OH CHO OH OH OH OH OH OH OH OH OH 不需指明α、β时 D B-D CH,OH Haworth式二者互为异构体 O OH HOH OH OHα-D β-D Haworth 式二者互为异构体 HOH OH OH OH CH2OH O 不需指明α 、β时 CH2OH H OH H OH HO H H OH CHO CHO OH OH H H H OH OH H HOCH2 CHO OH OH OH OH CH2OH 1 3 2 4 5 6 CHO OH OH OH CH2OH OH 1 3 2 4 5 6 OH OH OH OH CH2OH O + OH OH OH OH CH2OH O