1 H - NMR ( 300 MHz , DMSO - d 6 ) : 0 . 80 ( t , J = 6 . 0 Hz , 3 H ) , 1 . 28 ( q , J = 6 . 0 Hz , 2 H ) , 3 . 14 ( s , 4 H ) , 3 . 56 ( s , 2 H ) , 4 . 3 ( brs , 2 H ) , 4 . 41 ( s , 2 H ) , 12 . 9 ( brs , 1 H )