1 H NMR ( 400 MHz , CDCl 3 ) δ 9 . 36 ( s , 1 H ) , 9 . 11 ( br d , J = 9 Hz , 1 H ) , 8 . 12 ( d , J = 2 . 0 Hz , 1 H ) , 7 . 98 ( d , J = 8 . 9 Hz , 1 H ) , 7 . 73 ( dd , J = 8 . 9 , 2 . 2 Hz , 1 H ) , 4 . 21 - 4 . 33 ( m , 1 H ) , 4 . 08 - 4 . 15 ( m , 1 H ) , 3 . 50 - 3 . 60 ( m , 2 H ) , 2 . 11 - 2 . 22 ( m , 2 H ) , 1 . 77 ( dddd , J = 12 , 12 , 12 , 5 Hz , 1 H ) , 1 . 49 ( ddd , J = 12 , 12 , 11 Hz , 1 H ) , 1 . 28 ( d , J = 6 . 2 Hz , 3 H ) .