| abstract |
A cyclic tetrapeptide derivative represented by the general formula (I):wherein:R11, R12, R21 and R22 independently denote a monovalent group selected from hydrogen, a linear or branched alkyl group with 6 or less carbon atoms, benzyl group, 4-methoxybenzyl group, 3-indolylmethyl group, (N-methoxy-3-indolyl) methyl group, (N-formyl-3-indolyl)methyl group, etc.; R3 denotes a divalent group selected from a linear chained hydrocarbon group with 3 or 4 carbon atoms, or the linear branched hydrocarbon group having a branched chain added to the chain, or a divalent group substituted with a heteroatom;R4 denotes a divalent chained hydrocarbon group with 4 to 6 carbon atoms, or a divalent group derived from said hydrocarbon group by addition etc. of a branched chain on said chain; and a pharmaceutically acceptable salt thereof, or an analogous cyclic tetrapeptide derivative compound; as well as a histone deacetylase enzyme inhibitor, an MHC class-I molecule expression promoting agent and a pharmaceutical composition that comprise said cyclic tetrapeptide derivative as an effective ingredient. |