1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 1 . 01 - 1 . 03 ( 3 H , m ) , 1 . 26 ( 3 H , d ) , 2 . 34 - 2 . 37 ( 1 H , m ) , 2 . 80 - 2 . 84 ( 1 H , m ) , 3 . 11 ( 1 H , t ) , 3 . 44 - 3 . 48 ( 1 H , m ) , 3 . 53 ( 1 H , d ) , 3 . 66 ( 1 H , d ) , 3 . 93 ( 1 H , d ) , 4 . 42 ( 1 H , s ) , 7 . 24 - 7 . 30 ( 1 H , m ) , 7 . 31 - 7 . 41 ( 4 H , m ) , 7 . 56 - 7 . 59 ( 1 H , m ) , 8 . 22 - 8 . 26 ( 1 H , m ) ; m / z = 391 [ M + H ] +.