6  5  US 9,523,914 B2  enylene, or C$_{2}$ -C$_{20 }$ alkynylene group, R 2  and Rs each are  hydrogen or a straight, branched or cyclic C$_{1 }$-C$_{12 }$ alkyl  group, or R 2  may bond with R$^{1 }$to form a ring, and Rs may  bond with R$^{4 }$to form a ring, R$^{3 }$and R $^{6 }$each are an acid labile  group, X$_{1 }$ to X$_{6 }$ each are hydrogen, hydroxyl, alkoxy, acy- loxy or carbonyl group.  Examples of the cholanoate having an acid labile group› protected amino group, represented by formula  (1 )-1 or (1  )-2  are shown below, but not limited thereto.  -continued  HO  0  0  O  0  0  Ao  0  H  H  H  H  H  H  /’-y~  0  0  I  y  ’R3  0  H  ~  N  0  0  y  ’R 3  0  H  o~NYo’R3  0  H  o~NYo’R3  0  0  O~N}-.__O,,,,R 3  H  H  o~NYo’R3  0  OJ:]N-<O  3  0-R  HO’’’~••  H  0  oD)l_o ✓R'  0  Ao,,•••  H  H  N  0  0/  y  ’R 3  0  0  H  0  )l  R3  O~N  0/  H  0  H  H  ~  N  0  0  y  ’R 3  0  0  H  0  A  R3  O~N  0/  H  0  H 