A heterocyclic compound represented by the general formula (1) or a salt thereof:wherein m, l, and n respectively represent an integer of 1 or 2； X represents -O- or -CH2-； R1 represents hydrogen, a lower alkyl group, a hydroxy-lower alkyl group, a protecting group, or a tri-lower alkylsilyloxy-lower alkyl group； R2 and R3, which are the same or different, each independently represent hydrogen or a lower alkyl group； or R2 and R3 are bonded to form a cyclo-C3-C8 alkyl group； and R4 represents an aromatic group or a heterocyclic group, wherein the aromatic or heterocyclic group may have one or more arbitrary substituent(s).一種通式(1)所示之雜環化合物或其鹽：其中m、1及n分別表示1或2的整數；X表示-O-或-CH2-；R1表示氫、低級烷基、羥基-低級烷基、保護基，或三-低級烷基矽氧基-低級烷基；R2及R3，彼等可為相同或不同，各自獨立地表示氫或低級烷基；或R2及R3係鍵結而形成環-C3-C8烷基；及R4表示芳香族基或雜環基，其中該芳香族或雜環基可具有一或多個任意取代基。
