1 H NMR ( 300 MHz , CDCl 3 ) δ 1 . 71 - 2 . 04 ( 3 H , m ) , 2 . 04 - 2 . 21 ( 1 H , m ) , 3 . 20 - 3 . 32 ( 2 H , m ) , 3 . 46 ( 2 H , t , J = 6 . 1 Hz ) , 3 . 80 ( 2 H , t , J = 6 . 6 Hz ) , 4 . 03 ( 1 H , t , J = 5 . 7 Hz ) , 6 . 96 ( 1 H , d , J = 3 . 8 Hz ) , 7 . 25 - 7 . 33 ( 1 H , m ) , 7 . 35 ( 1 H , d , J = 3 . 8 Hz ) , 7 . 37 - 7 . 46 ( 2 H , m ) , 7 . 57 - 7 . 65 ( 2 H , m ) .