1 H 　 NMR ( DMSO - d 6 , 400 MHz ) δ 9 . 28 ( s , 1 H ) , 8 . 61 ( s , 1 H ) , 7 . 97 ( s , 1 H ) , 7 . 92 - 7 . 67 ( m , 2 H ) , 6 . 99 ( d , J = 8 Hz , 2 H ) , 6 . 84 ( s , 1 H ) , 6 . 76 ( s , 1 H ) , 6 . 68 - 6 . 47 ( m , 1 H ) , 3 . 92 ( s , 3 H ) , 3 . 81 ( s , 3 H ) , 3 . 13 ( brs , 4 H ) , 2 . 53 ( brs , 4 H ) , 2 . 41 - 2 . 39 ( m , 2 H ) , 1 . 04 ( t , J = 6 Hz , 3 H ) .