< Conversion 1 > Showing the double bond each dotted line with when X is N and CH, when and X includes double bond, that is C R is OR and NH SOR When R is hydrogen, and X C or is CH, R to be able also be C alkyl R hydrogen, is C alkyl, C alkoxy C alkyl or C shikuroarukiru n is 3, 4, 5 or 6 R and R, the nitrogen atom which those connect and becoming simultaneous, to form two cyclic ring systems which are chosen from formula (ii), as for the said ring system, it to be possible here to be substituted with 1 - 3 substituents by when R hydrogen Aryl Het C shikuroarukiru which can be substituted with C alkyl by when Or with when C shikuroarukiru, it is C alkyl which can be substituted with aryl or Het R aryl Het C shikuroarukiru which can be substituted with C alkyl by when Or with when C shikuroarukiru, it is C alkyl which can be substituted with aryl or Het Aryl to be phenyl or naphthyl, as for those each one, it to be possible to be substituted with 1 - 3 substituents by when Het, becoming independent from each one N, O or S, 5 or 6 member saturations which can contain 1 - 4 hetero atoms which are chosen be substituted with 1 - 3 substituents by when, part the inhibiter and its N oxide of the HCV duplication formula (i) it is unsaturated complex cyclic ring unsaturated or completely, the salt or stereoisomer, production method of the medicine manufacture study composition and chemical compound (i) it contains chemical compound (i). Also living thing utilization characteristic combination with inhibiter and ritonabiru of HCV formula (i) is offered.【化1】各点線が場合による二重結合を示し;XがN、CHであり、そしてXが二重結合を含む場合、それはCであり;R1が-OR6、-NH-SO2R7であり;R2が水素であり、そしてXがC又はCHである場合、R2はC1-6アルキルであることもでき;R3が水素、C1-6アルキル、C1-6アルコキシC1-6アルキル又はC3-7シクロアルキルであり;nが3、4、5又は6であり;R4及びR5が、それらが結合する窒素原子と一緒になって、式(II)から選ばれる二環式環系を形成し、ここで該環系は場合により1~3個の置換基で置換されていることができ;R6が水素;アリール;Het;場合によりC1-6アルキルで置換されていることができるC3-7シクロアルキル;あるいは場合によりC3-7シクロアルキル、アリール又はHetで置換されていることができるC1-6アルキルであり;R7がアリール;Het;場合によりC1-6アルキルで置換されていることができるC3-7シクロアルキル
