1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 07 - 1 . 47 ( m , 4 H ) , 1 . 65 - 1 . 83 ( m , 4 H ) , 1 . 55 - 1 . 99 ( m , 2 H ) , 2 . 21 - 2 . 25 ( m , 2 H ) , 3 . 52 ( br s , 1 H ) , 3 . 66 - 3 . 77 ( m , 1 H ) , 3 . 93 ( s , 3 H ) , 4 . 21 ( s , 3 H ) , 6 . 22 ( d , 1 H , J = 12 . 3 Hz ) , 6 . 72 ( d , 1 H , J = 2 . 4 Hz ) , 7 . 02 ( d , 1 H , J = 12 . 3 Hz ) , 7 . 33 ( s , 1 H ) , 7 . 61 ( d , 1 H , J = 2 . 4 Hz ) , 8 . 03 ( br s , 1 H )