1 H NMR ( 300 MHz , DMSO - d 6 ) δ 7 . 37 - 7 . 44 ( m , 1 H ) , 7 . 07 ( s , 1 H ) , 6 . 99 - 7 . 03 ( m , 1 H ) , 6 . 94 ( s , 2 H ) , 6 . 55 ( d , J = 5 . 7 Hz , 1 H ) , 5 . 70 - 5 . 75 ( m , 1 H ) , 4 . 30 - 4 . 38 ( m , 1 H ) , 4 . 12 - 4 . 13 ( m , 1 H ) , 3 . 97 - 4 . 08 ( m , 2 H ) , 3 . 74 ( s , 3 H ) , 3 . 01 ( s , 3 H ) , 1 . 33 ( t , J = 7 . 2 Hz , 3 H ) .