Disclosed is a compound represented by the formula (I) or a pharmaceuticallyacceptable salt thereof, which has a glucokinase-activating activity and istherefore useful for the treatment of diabetes or obesity. (I) wherein Rand R independently represent a lower alkyl group； and Xrepresents a group represented by the formula (II-1): (II-1) where Rand R independently represent a hydrogen atom or a lower alkyl group,or R and R together with a nitrogen atom to which Rand R are bonded may form a 4- to 7-membered nitrogenated aliphaticring (wherein one of the carbon atoms constituting the 4- to 7-membered nitrogenatedaliphatic ring may be substituted by an oxygen atom), or R and Rtogether with any carbon atom in the group (CH) may forma 4- to 7-membered nitrogenated aliphatic ring or the like； and m represents aninteger of 1 to 3.
