1 H NMR ( 300 MHz , CDCl 3 ) δ 2 . 35 ( 3 H , s ) , 4 . 54 ( 2 H , brs ) , 6 . 74 ( 1 H , dd , J = 7 . 3 , 5 . 1 Hz ) , 6 . 97 ( 2 H , d , J = 8 . 7 Hz ) , 7 . 05 ( 2 H , d , J = 8 . 7 Hz ) , 7 . 18 ( 2 H , d , J = 8 . 3 Hz ) , 7 . 32 - 7 . 41 ( 3 H , m ) , 8 . 06 ( 1 H , dd , J = 4 . 9 , 1 . 9 Hz ) .