1 H 　 NMR ( DMSO - d 6 , 400 MHz ) δ 9 . 07 ( s , 1 H ) , 7 . 56 ( m , 2 H ) , 7 . 56 ( d , J = 11 . 8 Hz , 17 H ) , 7 . 54 ( s , 1 H ) , 6 . 98 ( d , 2 H ) , 6 . 83 ( s , 1 H ) , 6 . 71 ( s , 1 H ) , 3 . 91 ( s , 3 H ) , 3 . 80 ( s , 3 H ) , 3 . 58 ( s , 3 H ) , 3 . 17 ( m , 4 H ) , 2 . 67 ( m , 4 H ) , 1 . 77 ( q , 2 H ) , 1 . 10 ( t , 3 H ) .