1 H NMR ( 400 . 1 MHz , CDCl 3 ) δ 1 . 23 - 1 . 25 ( 3 H , m ) , 1 . 33 ( 3 H , d ) , 2 . 71 - 2 . 75 ( 1 H , m ) , 3 . 32 - 3 . 39 ( 2 H , m ) , 3 . 47 ( 1 H , d ) , 3 . 59 - 3 . 64 ( 1 H , m ) , 4 . 15 - 4 . 19 ( 1 H , m ) , 7 . 04 ( 1 H , d ) , 7 . 92 ( 1 H , d ) ; m / z = 301 [ M + H ] +.