1 H NMR ( 399 . 9 MHz , CDCl 3 ) δ 2 . 58 - 2 . 69 ( 4 H , m ) , 3 . 60 - 3 . 75 ( 6 H , m ) , 7 . 06 ( 1 H , d ) , 7 . 70 ( 1 H , d ) , 7 . 83 - 7 . 90 ( 1 H , m ) , 7 . 95 ( 1 H , d ) , 8 . 71 ( 1 H , s ) ; m / z = 390 [ M + H ] +.