1 H NMR ( 400 MHz , DMSO - d 6 ) δ 9 . 33 ( s , 1 H ) , 7 . 86 - 7 . 78 ( m , 2 H ) , 7 . 63 ( d , J = 6 . 8 Hz , 1 H ) , 7 . 27 ( d , J = 8 . 0 Hz , 1 H ) , 7 . 02 ( d , J = 8 . 4 Hz , 1 H ) , 5 . 80 ( dd , J = 10 . 0 , 3 . 6 Hz , 1 H ) , 4 . 34 - 4 . 29 ( m , 1 H ) , 4 . 22 - 4 . 16 ( m , 3 H ) , 3 . 76 ( s , 3 H ) , 3 . 28 ( s , 3 H ) , 3 . 09 ( s , 3 H ) , 1 . 18 ( t , J = 7 . 2 Hz , 3 H ) , LCMS ( ESI ) [ M + H ] + = 498 . 1 .