1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 28 ( m , 2 H ) , 1 . 62 ( brd , 2 H ) , 1 . 72 - 1 . 91 ( m , 4 H ) , 2 . 21 ( s , 3 H ) , 2 . 22 ( t , 2 H ) , 2 . 33 ( m , 1 H ) , 2 . 65 ( brd , 2 H ) 4 . 43 ( t , 2 H ) , 4 . 84 ( brs , 1 H , NH 2 ) , 5 . 70 ( brs , 1 H , NH 2 ) , 6 . 88 ( d , 1 H , J = 7 . 8 Hz ) , 7 . 24 ( m , 2 H ) , 7 . 48 ( d , 1 H ) , 7 . 53 ( d , 2 H , J = 8 . 7 Hz ) , 7 . 57 ( m , 1 H ) , 7 . 71 ( d , 2 H , J = 8 . 7 Hz ) , 7 . 80 ( s , 1 H ) , 7 . 90 ( dd , 1 H , J = 8 . 7 Hz , 1 . 5 Hz ) , 8 . 32 ( d , 1 H , J = 1 . 5 Hz ) ; MS ( m / e , M +): 530