1 H NMR ( DMSO - d 6 ) δ 9 . 31 ( 1 H , br ) , 8 . 61 ( 1 H , br d , J = 4 . 9 Hz ) , 7 . 64 ( 1 H , d , J = 7 . 9 Hz ) , 7 . 41 ( 1 H , dd , J = 7 . 9 , 4 . 9 Hz ) , 7 . 32 ( 1 H , m ) , 7 . 22 ( 1 H , m ) , 4 . 45 ( 1 H , dd , J = 15 . 3 , 5 . 5 Hz ) , 4 . 41 ( 1 H , dd , J = 15 . 3 , 5 . 5 Hz ) , 3 . 43 ( 1 H , d , J = 6 . 1 Hz ) , 3 . 05 ( 1 H , d , J = 6 . 1 Hz ) , 2 . 50 ( 1 H , m ) , 2 . 38 - 2 . 23 ( 2 H , m ) , 2 . 12 ( 1 H , m ) .