4-tert-butoxycarbonylamino-3-hydroxy-5-(4-hydroxyphenyl)-2-(2,3,4,5,6-pentafluorophenyl)-2-pentenenitrile
4-tert-butoxycarbonylamino-3-hydroxy-5-(4-hydroxyphenyl)-2-(2,3,4,5,6-pentafluorophenyl)-2-pentenenitrile