1 H NMR ( 400 MHz , DMSO - d 6 ) : δ 7 . 24 ( d , J = 8 . 0 Hz , 1 H ) , 6 . 98 ( d , J = 8 . 0 Hz , 1 H ) , 4 . 31 - 4 . 39 ( m , 2 H ) , 4 . 21 - 4 . 25 ( m , 1 H ) , 3 . 76 ( s , 3 H ) , 3 . 36 - 3 . 43 ( m , 2 H ) , 3 . 02 ( s , 3 H ) , 2 . 32 ( s , 2 H ) , 1 . 32 ( t , J = 7 . 2 Hz , 3 H ) .