1 H - NMR ( 300 MHz , DMSO - d 6 ) : 0 . 79 ( t , J = 6 . 0 Hz , 3 H ) , 1 . 25 ( q , J = 6 . 0 Hz , 2 H ) , 3 . 26 ( s , 4 H ) , 4 . 01 ( s , 2 H ) , 4 . 3 ( brs , 2 H ) , 7 . 83 ( m , 2 H ) , 8 . 15 ( m , 2 H ) , 12 . 2 ( brs , 1 H )