Diethyl piperazine-1,4-diyldioxalate

Abstract

The ethyl oxamate group, N-C(O)-C(O)-OEt, in the title compound, alternatively called diethyl N,N':N,N'-bis(ethylene)dioxamate, C12H18N2O6, can be considered as being composed of two singly bonded amide and ester functionalities. The ethyl oxamate group is not planar. The two carbonyl groups are almost perpendicular, with an oxalyl O=C-C=O torsion angle of -111.34 (17) degrees. The molecule is located on an inversion centre. Infinite supramolecular tapes, propagating along the b axis, are formed through soft C-H...O interactions which form a centrosymmetric R(2)2(12) motif.

DiethylN,N′-cyclohexane-1,4-diyldioxalamate

“…The central cyclohexyl group adopts a chair conformation bearing the two ethyl oxalyl groups in equatorial position. The N4-C1 bond length is 1.457 (3) Å and the N4-C5 bond length is 1.321 (3) Å , this latter being significantly shorter than the values found in other aliphatic [1.3603 (19) Å ;Martínez-Martínez et al, 2004] or even aromatic [1.348 (3) Å ; García-Bá ez et al, 2003] ethyl oxalamates, suggesting a strong electron delocalization from atom N4 to the C5 O5 carbonyl group. This result is supported by the longer bond length exhibited by the amide O5 C5 carbonyl group of 1.221 (3) Å relative to that of the ester O6 C6 carbonyl group of 1.193 (3) Å , which makes the former carbonyl the best hydrogen-bonding acceptor (see below).…”

N,N′-Dibenzoylpiperazine

“…1). The piperazine ring exhibits a chair conformation with the usual bond lengths and angles (Table 1) (Martínez-Martínez et al, 2004;Yogavel et al, 2003). The sum of angles around atom N1 is 360.0 , and the N1-C7 bond length is 1.354 (18) Å , in accordance with the Nsp 2 -Csp 2 amide character [1.355 (14) Å ; Allen et al, 1987].…”