The present invention discloses compounds of formula (I) any of its enantiomers or any mixture thereof, isotopes thereof or a pharmaceutically acceptable salt thereof, wherein n is 1, 2 or 3; m is 0, 1 or 2; R represents hydrogen, alkyl, cycloalkyl, cycloalkylalkyl or aralkyl; and R1 represents aminophenyl; nitrophenyl; hydroxyphenyl, alkoxyphenyl; a monocyclic 5 to 6 membered heterocyclic group which may be substituted one or more times with substituents or R1 represents a bicyclic heterocyclic group, composed of 5 to 6 membered monocyclic heterocyclic group fused to a benzene ring, and which may be substituted one or more times with substituents. The compounds of the invention are useful as nicotinic ACh receptor ligands.