1 H NMR ( CDCl 3 ) δ 8 . 66 - 8 . 60 ( 1 H , m ) , 7 . 68 ( 1 H , dd , J = 7 . 9 , 1 . 8 Hz ) , 7 . 45 ( 0 . 5 H , d , J = 1 . 8 Hz ) , 7 . 39 ( 0 . 5 H , d , J = 1 . 8 Hz ) , 7 . 37 - 7 . 21 ( 3 H , m ) , 7 . 15 ( 0 . 5 H , br ) , 7 . 00 ( 0 . 5 H , br ) , 4 . 62 - 4 . 50 ( 2 H , m ) , 4 . 44 ( 1 H , m ) , 3 . 30 ( 1 . 5 H , s ) , 3 . 16 ( 1 . 5 H , s ) , 3 . 03 - 2 . 62 ( 3 H , m ) , 2 . 42 - 2 . 27 ( 1 H , m ) .