Conformation of N-methyl-4-piperidyl 2,4-dinitrobenzoate

The crystal structure of N-methyl-4-piperidyl 2,4-dinitrobenzoate, C(13)H(15)N(3)O(6), (I), at 130 (2) K reveals that, in the solid state, the molecule exists in the equatorial conformation, (Ieq). Thus, the through-bond interaction present in the axial conformation, (Iax), is not strong enough to overcome the syn-diaxial interactions between the axial methyl substituent and the axial H atoms on the two piperidyl ring C atoms either side of the ester-linked ring C atom. The carboxylate group in (I) is orthogonal to the aromatic ring, in contrast with other 2,4-dinitrobenzoates, which are coplanar. The piperidyl-ester C-O bond distance is 1.467 (3) A, which is actually shorter than other equatorial cyclohexyl-ester C-O distances. This shorter piperidyl-ester C-O bond distance is due to the reduced electron demand of the orthogonal ester group.