| abstract |
A heterocyclic compound represented by the following formula (1) or a salt thereof: Wherein m, l, and n each represent an integer of 1 or 2; X is -O- or -CH 2 - represents; R 1 represents hydrogen, a lower alkyl group, a hydroxy-lower alkyl group, a protecting group, or a tri-lower alkylsilyloxy-lower alkyl group; R 2 and R 3 are the same or different and each independently represent hydrogen or a lower alkyl group; Or R 2 and R 3 are combined to form a cyclo-C 3 -C 8 alkyl group; And R 4 represents an aromatic group or a heterocyclic group, The aromatic or heterocyclic group may have one or more optional substituent (s). |