1 H NMR ( CDCl 3 ) δ 8 . 38 ( 1 H , d , J = 1 . 2 Hz ) , 7 . 52 ( 1 H , d , J = 1 . 2 Hz ) , 6 . 29 ( 1 H , d , J = 1 . 2 Hz ) , 5 . 18 ( 1 H , d , J = 1 . 2 Hz ) , 4 . 02 ( 1 H , m ) , 2 . 88 ( 1 H , m ) , 2 . 66 ( 1 H , m ) , 2 . 36 ( 3 H , s ) , 2 . 31 ( 1 H , m ) , 2 . 17 ( 1 H , m ) .