A compound selected from the group consisting of: 2-(4-(2-(4,4-diethyl-5-oxotetrahydrofuran-2-yl)ethyl)piperazin-1-yl)benzonitrile; 3,3-diethyl-5-(2-(4-(4-methoxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(4-hydroxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(4-nitrophenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 4-(4-(2-(4,4-diethyl-5-oxotetrahydrofuran-2-yl)ethyl)piperazin-1-yl)benzonitrile; 3,3-diethyl-5-(2-(4-(2-hydroxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 5-(2-(4-(4-aminophenyl)piperazin-1-yl)ethyl)-3,3-diethyldihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(p-tolyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(3-methoxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(3-hydroxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 5-(2-(4-(2,6-dimethylphenyl)piperazin-1-yl)ethyl)-3,3-diethyldihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(o-tolyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(2-isopropylphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 5-(2-(4-(2,4-dimethylphenyl)piperazin-1-yl)ethyl)-3,3-diethyldihydrofuran-2 -one; 3-(2-(4-(2-isopropylphenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-(tert-butyl)phenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2,6-diisopropylphenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-morpholinophenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-([1,1'-biphenyl]-2-yl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-(1H-pyrrol-1-yl)phenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-iodophenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; N-(2-(4-(2-(1-oxo-2-oxaspiro[4.4]nonan-3-yl)ethyl)piperazin-1-yl)phenyl)acetamide; 5-nitro-2-(4-(2-(1-oxo-2-oxaspiro[4.4]nonan-3-yl)ethyl)piperazin-1-yl)benzonitrile; and 3-(2-(4-(p-tolyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; or a pharmaceutically acceptable salt thereof. 2-(4-(2-(4,4-diethyl-5-oxotetrahydrofuran-2-yl)ethyl)piperazin-1-yl)benzonitrile; 3,3-diethyl-5-(2-(4-(4-methoxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(4-hydroxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(4-nitrophenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 4-(4-(2-(4,4-diethyl-5-oxotetrahydrofuran-2-yl)ethyl)piperazin-1-yl)benzonitrile; 3,3-diethyl-5-(2-(4-(2-hydroxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 5-(2-(4-(4-aminophenyl)piperazin-1-yl)ethyl)-3,3-diethyldihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(p-tolyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(3-methoxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(3-hydroxyphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 5-(2-(4-(2,6-dimethylphenyl)piperazin-1-yl)ethyl)-3,3-diethyldihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(o-tolyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 3,3-diethyl-5-(2-(4-(2-isopropylphenyl)piperazin-1-yl)ethyl)dihydrofuran-2 -one; 5-(2-(4-(2,4-dimethylphenyl)piperazin-1-yl)ethyl)-3,3-diethyldihydrofuran-2 -one; 3-(2-(4-(2-isopropylphenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-(tert-butyl)phenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2,6-diisopropylphenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-morpholinophenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-([1,1'-biphenyl]-2-yl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-(1H-pyrrol-1-yl)phenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; 3-(2-(4-(2-iodophenyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one; N-(2-(4-(2-(1-oxo-2-oxaspiro[4.4]nonan-3-yl)ethyl)piperazin-1-yl)phenyl)acetamide; 5-nitro-2-(4-(2-(1-oxo-2-oxaspiro[4.4]nonan-3-yl)ethyl)piperazin-1-yl)benzonitrile; and 3-(2-(4-(p-tolyl)piperazin-1-yl)ethyl)-2-oxaspiro[4.4]nonan-1-one;