1 H NMR ( 399 . 9 MHz , CDCl 3 ) δ 2 . 49 ( 1 H , t ) , 3 . 07 ( 3 H , s ) , 4 . 79 ( 2 H , d ) , 7 . 36 - 7 . 40 ( 1 H , m ) , 7 . 51 - 7 . 54 ( 1 H , m ) , 7 . 72 ( 1 H , s ) ; m / z = 203 [ M - H ] -.