The marine natural product Psammaplin A(PSA),a brominated tyrosine derivative,was reported to inhibit in vitro HDACs(IC50=4.2nM) and DNMTs (IC50=18.6nM).Keeping symmetry of PSA,introduction of different substituents in benzene ring and O-methylation of hydroxyimino fragment were done to attain fifteen compounds(A01~A15).Reports say the small molecules containing free thiol compounds can inhibit HDACs.So,we change the symmetry of PSA,fifteen compounds of free thiol(B01~B15) were designed and synthesized.