1 H NMR ( 400 MHz , DMSO - d 6 ) δ 10 . 29 ( s , 1 H ) , 8 . 72 ( d , J = 8 . 4 Hz , 1 H ) , 7 . 86 ( t , J = 8 . 4 Hz , 1 H ) , 7 . 62 ( d , J = 6 . 8 Hz , 1 H ) , 7 . 27 ( d , J = 8 . 0 Hz , 1 H ) , 7 . 04 ( d , J = 8 . 0 Hz , 1 H ) , 5 . 81 ( dd , J = 10 . 8 , 3 . 6 Hz , 1 H ) , 4 . 34 - 4 . 30 ( m , 1 H ) , 4 . 23 - 4 . 15 ( m , 3 H ) , 4 . 10 ( s , 2 H ) , 3 . 76 ( s , 3 H ) , 3 . 45 ( s , 3 H ) , 3 . 10 ( s , 3 H ) , 1 . 17 ( t , J = 7 . 2 Hz , 3 H ) . LCMS : [ M + H ] + = 492 . 2 .