-continued  -continued  46  US 8,900,791 B2  45  H  N~OH  ~  (AlS)  (A22)  ~  HO  ~  (A23)  OH  0  ~  (A24)  OH  :yC(~  0  ~  0 ~0H  (A25)  *  0  ~  OH  ;:co  a  a  (A21)  0  HN~OH  ¢  ~  (A20)  0  HN~OH  ¢  ~  (A19) 