3-{[(tert-butoxy)carbonyl](2-ethoxyethyl)amino}propanoic acid

3-{[(tert-butoxy)carbonyl][2-(dimethylamino)ethyl]amino}propanoic acid

3-{[(tert-butoxy)carbonyl](3-methylbutan-2-yl)amino}propanoic acid

3-{[(tert-butoxy)carbonyl][2-(diethylamino)ethyl]amino}propanoic acid

3-{[(tert-butoxy)carbonyl](3-phenylpropyl)amino}propanoic acid

3-{[(tert-butoxy)carbonyl][(2-chlorophenyl)methyl]amino}propanoic acid

3-{[(tert-butoxy)carbonyl](2,2-diethoxyethyl)amino}propanoic acid

3-{[(tert-butoxy)carbonyl][3-(propan-2-yloxy)propyl]amino}propanoic acid

tert-butyl 3-(cyclohexylamino)propanoate

tert-butyl 3-(propylamino)propanoate

tert-butyl 3-(pentylamino)propanoate