ethyl 3-{[3-(dimethylamino)-2,2-dimethylpropyl]amino}propanoate

tert-butyl 2-methyl-3-{[3-(propan-2-yloxy)propyl]amino}propanoate

methyl 3-(butylamino)butanoate

methyl 3-(hexylamino)butanoate

methyl 3-(pentylamino)butanoate

methyl 3-{[(4-fluorophenyl)methyl]amino}butanoate

methyl 3-{[3-(dimethylamino)propyl]amino}-2-methylpropanoate

methyl 2-methyl-3-[(4-phenylbutan-2-yl)amino]propanoate

methyl 3-{[2-(4-fluorophenyl)ethyl]amino}butanoate

methyl 3-{[3-(propan-2-yloxy)propyl]amino}butanoate

ethyl 3-(dipropylamino)propanoate