1 H NMR ( CDCl 3 ) δ 8 . 66 ( 1 H , dt , J = 4 . 7 , 1 . 8 Hz ) , 7 . 54 ( 1 H , d , J = 7 . 6 Hz ) , 7 . 46 ( 1 H , d , J = 2 . 1 Hz ) , 7 . 39 ( 1 H , d , J = 8 . 2 Hz ) , 7 . 27 - 7 . 33 ( 2 H , m ) , 7 . 13 - 7 . 25 ( 1 H , m ) , 6 . 10 ( 1 H , br s ) , 4 . 58 - 4 . 69 ( 2 H , m ) , 4 . 34 ( 1 H , dd , J = 12 . 2 , 2 . 3 Hz ) , 4 . 17 ( 2 H , dd , J = 16 . 8 , 15 . 5 Hz ) , 3 . 37 ( 1 H , dd , J = 12 . 2 , 3 . 0 Hz ) 2 . 77 - 2 . 95 ( 1 H , m ) , 2 . 41 - 2 . 49 ( 1 H , m ) , 2 . 08 - 2 . 30 ( 2 H , m ) .