1 H - NMR ( 300 MHz , DMSO - d 6 ) : 0 . 83 ( t , J = 6 . 0 Hz , 3 H ) , 1 . 64 ( q , J = 6 . 0 Hz , 2 H ) , 1 . 5 - 1 . 8 ( m , 6 H ) , 3 . 35 ( t , 2 H ) , 3 . 39 ( s , 4 H ) , 3 . 79 ( s , 2 H ) , 4 . 2 ( brs , 2 H )