1 H - NMR ( CDCl 3 ) : 7 . 875 ( d , 1 H , J = 8 . 8 Hz ) , 7 . 640 ( d , 2 H , J = 8 . 4 Hz ) , 7 . 223 ( d , 2 H , J = 8 Hz ) , 7 . 042 ( d , 1 H , J = 8 . 4 Hz ) , 6 . 890 ( d , 1 H , J = 2 . 8 Hz ) , 6 . 703 ( s , 1 H ) , 6 . 627 ( d , 1 H , J = 8 . 4 Hz ) , 5 . 046 ( s , 2 H ) , 4 . 546 ( s , 2 H ) , 3 . 794 ( s , 3 H ) , 3 . 1 ( br , 1 H ) , 2 . 749 ( t , 2 H , J = 6 . 8 Hz ) , 2 . 415 ( s , 3 H ) , 1 . 741 ( t , 2 H , J = 6 . 4 Hz ) , 1 . 332 ( s , 6 H )