38  US 7,344,821 B2  37  21  ~Ou  CH$_{3 }$ 0  I  CH$_{3 }$ 22  H  ===you  CH$_{3 }$ 0  I  CH$_{3 }$ 23  0  24  25  26  ~  CH;  oou  27  m,Q  ~ocSH,  28  HQ  ~ocSH,  11  12  ~:b  13  ~:b  14  ~ofro  15  ~ofro  16  ~otD  17 ~otD  18  ~o~  H3C+J)  CH$_{3 }$ 19  ~o~  H3C+J)  CH$_{3 }$ 20 -continued  -continued 