1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 29 ( s , 1 H ) , 8 . 72 - 8 . 67 ( m , 2 H ) , 8 . 59 ( s , 1 H ) , 8 . 24 ( d , J = 8 . 9 Hz , 1 H ) , 7 . 66 ( dd , J = 8 . 9 , 2 . 1 Hz , 1 H ) , 5 . 31 ( br s , 1 H ) , 4 . 87 ( d , J = 5 . 4 Hz , 2 H ) , 4 . 73 ( s , 2 H ) , 4 . 34 ( dd , J = 12 . 1 , 5 . 2 Hz , 1 H ) , 3 . 74 ( br s , 2 H ) , 2 . 91 ( br s , 1 H ) , 2 . 76 ( br s , 1 H ) , 2 . 48 ( br s , 1 H ) , 1 . 88 ( br s , 1 H ) , 1 . 75 ( br s , 1 H ) , 1 . 38 ( d , J = 6 . 1 Hz , 3 H ) .