1 H - NMR ( 300 MHz , CDCl 3 ) δ 1 . 25 ( d , 6 H ) , 1 . 69 - 1 . 78 ( m , 4 H ) , 1 . 83 ( brd , 2 H ) , 2 . 05 ( t , 2 H ) , 2 . 50 ( m , 1 H ) , 2 . 55 ( m , 1 H ) , 2 . 66 ( t , 2 H ) , 3 . 17 ( brd , 2 H ) , 3 . 83 ( t , 2 H ) , 6 . 92 ( d , 1 H ) , 7 . 23 ( dd , 1 H ) , 7 . 35 - 7 . 38 ( m , 2 H ) , 7 . 40 ( s , 1 H , NH ) ; MS ( m / e , M +): 304