1 1 102 234 5 6a 6b 7 8 9 10 2The morphinan derivatives represented by general formula (I) (wherein Rrepresents hydrogen a Calkyl a cycloalkylalkyl in which the cycloalkyl moiety has 3 6 carbon atoms and the alkylene moiety has 1 5 carbon atoms or the like Rrepresents a heterocycle including at least one carbon atom and 1 4 heteroatoms selected from among N O and S as constituent annular atoms with at least one set of adjacent constituent annular atoms having a double bond said heterocycle also including at least one oxo group as a substituent Y is bonded to a carbon atom that is a constituent annular atom of R R Rand Rrepresent hydrogen hydroxy or the like Rand Rrepresent hydrogen or the like Rand Rrepresent hydrogen or the like Rand Rare the same or different and represent hydrogen or the like X represents O or CH and Y represents C(=O)) variants and stereoisomers of the derivatives pharmaceutically acceptable salts thereof and solvates thereof according to the present invention are used as antianxiety drugs antidepressants and the like.
