Patent Application  Publication  Jun. 15, 2017 Sheet  17 of 33  US  2017/0170505 Al  Figure 17:  Preparation  of a  polyethersulfone  containing  1-hydroxymethylene-l,  1-bisphosphonic  acid groups  via  lithiation  j  t  ,-Bu~HFl-60°C  H:,CO’ "0  l  0  "  $^{H-}$1 -0CH3  OC!-11  HN(Bu)2  148%  HB,, reflux, 24h  II  P-OH  I 