1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 61 ( m , 2 H ) , 1 . 72 ( brd , 2 H ) , 1 . 86 - 2 . 04 ( m , 4 H ) , 2 . 18 ( s , 3 H ) , 2 . 22 ( t , 2 H ) , 2 . 41 ( m , 1 H ) , 2 . 74 ( br , 2 H ) 4 . 44 ( t , 2 H ) , 4 . 83 ( brs , 1 H , NH 2 ) , 5 . 85 ( brs , 1 H , NH 2 ) , 6 . 92 ( d , 1 H , J = 7 . 4 Hz ) , 7 . 23 ( dd , 1 H ) , 7 . 36 ( s , 1 H ) , 7 . 43 ( d , 1 H , J = 7 . 8 Hz ) , 7 . 54 ( d , 2 H , J = 8 . 7 Hz ) , 7 . 69 ( m , 2 H ) , 7 . 49 ( d , 2 H , J = 8 . 7 Hz ) , 7 . 80 ( d , 1 H , J = 8 . 6 Hz ) , 8 . 30 ( s , 1 H ) ; MS ( m / e , M +): 530