Cyclobutanecarboxylic acid, 3-[[(1,1-dimethylethoxy)carbonyl]amino]-
3-[[(1,1-Dimethylethoxy)carbonyl]amino]cyclobutanecarboxylic acid
3-[[[tert-Butoxy)carbonyl]amino]cyclobutane-1-carboxylic acid
3-((tert-Butoxycarbonyl)amino)cyclobutanecarboxylic acid