1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 83 - 2 . 02 ( 3 H , m ) , 2 . 07 - 2 . 23 ( 1 H , m ) , 3 . 24 - 3 . 33 ( 2 H , m ) , 3 . 40 - 3 . 57 ( 2 H , m ) , 3 . 84 - 4 . 03 ( 3 H , m ) , 7 . 28 ( 2 H , d , J = 7 . 9 Hz ) , 7 . 58 ( 2 H , d , J = 7 . 9 Hz ) .