[Problem] To provide a compound that has an intestinal phosphate transporter(NPT-IIb)inhibitory action and is useful as an active ingredient of an agent fortreating and/orpreventing hyperphosphatemia.[Means for Solution] The present inventors conducted thier studies on acompound that hasan NPT-IIb inhibitory action and is useful as an active ingredient of an agentfor treatingand/or preventing hyperphosphatemia. As a result, they created an aminoalkyl-substitutedN-thienylbenzamide derivative which has NPT-IIb inhibitory action, therebycompleting the present invention. The aminoalkyl-substituted N-thienylbenzamidederivative of the present invention has an NPT-IIb inhibitory action and canbe used as anagent for preventing and/or treating hyperphosphatemia.
