Ethyl 4-(tert-butyl-amino)-3-nitro-benzoate.

In the title compound, C(13)H(18)N(2)O(4), intra-molecular N-H⋯O, N-H⋯N and C-H⋯O (× 3) hydrogen bonds generate S(6) and S(5) ring motifs. There are two crystallographically independent mol-ecules (A and B) in the asymmetric unit. The nitro group is coplanar with the benzene ring, with O-N-C-C torsion angles of -0.

Ethyl 3-nitro-4-(propyl-amino)benzoate.

In the title compound, C(12)H(16)N(2)O(4), intra-molecular N-H⋯O and C-H⋯O hydrogen bonds generate S(6) and S(5) ring motifs, respectively. The nitro group is almost coplanar with the benzene ring, forming a dihedral angle of 6.2 (2)°.