ethyl 4-{4-[bis(tert-butoxycarbonyl)amino]-3-[(2,4-dichlorobenzyl)amino]-5-methylphenoxy}butanoate

4-(4-amino-3-methyl-5-nitrophenoxy)butanoic acid

ethyl 4-(4-amino-3-methyl-5-nitrophenoxy)butanoate

ethyl 4-[4-(acetylamino)-3-methyl-5-nitrophenoxy]butanoate

ethyl 4-{4-[bis(tert-butoxycarbonyl)amino]-3-methyl-5-nitrophenoxy}butanoate