CO2Na CH2OH CO2Na CH2OH H O H O O H H O H H H O H O O OH OH H H H H OH H H H OH OH OH H H OH H NHCOCH3 H OH H NHCOCH3 n-1 CO2Na CH2OR2 CO2Na CH2OR2 H O OR1 O O OR1 H O H H H O H O O OH OH H H H H H OH H H H H OH H H OH H NHCOCH3 H OH H NHCOCH3 n-1 R1, R2=H OR SO3Na