1 H - NMR ( CDCl 3 ) δ 8 . 54 ( 1 H , dd , J = 2 . 7 , 1 . 3 Hz ) , 7 . 52 ( 1 H , d , J = 7 . 3 Hz ) 7 . 40 - 7 . 44 ( 1 H , m ) , 7 . 27 - 7 . 36 ( 2 H , m ) , 7 . 12 - 7 . 25 ( 3 H , m ) , 4 . 51 - 4 . 65 ( 2 H , m ) , 3 . 14 - 3 . 31 ( 2 H , m ) , 2 . 67 - 3 . 00 ( 2 H , m ) , 2 . 17 - 2 . 31 ( 2 H , m ) .