MC1568, a derivative of (Aryloxopropenyl)pyrrolyl hydroxyamide, is a novel, potent and specific inhibitor of class II histone deacetylase (HDAC), including two subclasses IIa (HDAC4, HDAC5, HDAC6, HDAC7 and HDAC9) and IIb (HDAC6 and HDAC 10), that exhibits strong inhibition against maize class II HDAC with 50% inhibition concentration IC50 value of 22 µM. MC1568 has been found to tissue-selectively inhibits HDAC and arrest myogenesis in cultured muscle cells through three possible mechanisms, including decreasing the expression of myocyte enhancer factor 2D, stabilizing the HDAC-HDAC3-MEF2D complex and inhibiting the acetylation of differentiation-induced MEF2D. Moreover, MC1568 is able to interfere with RAR- and PPARγ-mediated differentiation-inducing signaling pathways.