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. 2024 Oct 4;80(Pt 11):1130-1134.
doi: 10.1107/S205698902400954X. eCollection 2024 Oct 1.

N, N'-Di-benzyl-ethyl-enedi-ammonium dichloride

Mary Helene Marmande  1 , Bailey N Baxter  1 , Matthias Zeller  2 , David C Forbes  1
Affiliations

N, N'-Di-benzyl-ethyl-enedi-ammonium dichloride

Mary Helene Marmande et al. Acta Crystallogr E Crystallogr Commun. .

Abstract

The isolation and crystalline structure of N,N'-di-benzyl-ethyl-enedi-ammonium dichloride, C16H22N2 2+·2Cl-, is reported. This was obtained as an unintended product of an attempted Curtius rearrangement that involved benzyl-amine as one of the reagents and 1,2-di-chloro-ethane as the solvent. Part of a series of reactions of a course-based undergraduate research experience (CURE), this was not the intended reaction outcome. The goal of the course was to engage students as active participants in a laboratory experience which applies the foundational techniques of a synthetic organic laboratory, using the Curtius rearrangement as a tool for the assembly of medicinally significant scaffolds. The isolation of the title compound, N,N'-di-benzyl-ethyl-enedi-ammonium dichloride, the result of the 1,2-di-chloro-ethane solvent outcompeting the Curtius iso-cyanate inter-mediate in the reaction with the nucleophilic amine, confirms the importance of conducting research at the undergraduate level where the outcome is not predetermined. The solid-state structure of N,N'-di-benzyl-ethyl-enedi-ammonium dichloride was found to feature an all-trans methyl-ene-ammonium backbone. Strong N-H⋯Cl hydrogen bonds and C-H⋯Cl inter-actions lead to a layered structure with pseudo-translational symmetry emulating a C-centered setting. Different phenyl torsion angles at each end of the mol-ecule enable a more stable packing by allowing stronger hydrogen-bonding inter-actions, leading to a more ordered but lower symmetry and modulated structure in P21/n.

Keywords: crystal structure; hydrogen bonding; modulation; pseudo-translation; side reaction.

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Figures

Figure 1
Figure 1
The synthesis showing the intended product (top) and the product actually formed (bottom).
Figure 2
Figure 2
The title compound with the atom-labelling scheme and 50% probability ellipsoids. Unlabeled chloride anions are symmetry equivalent [1 − x, 2 − y, 1 − z for Cl1 (top), −x, 1 − y, 1 − z for Cl2 (bottom)].
Figure 3
Figure 3
Packing of the title compound showing N—H⋯Cl and C—H⋯Cl hydrogen bonds, the formation of layers and modulation of the phenyl rings. View down slightly angled from [1formula image0] (the modulation direction). 50% probability ellipsoids.
Figure 4
Figure 4
Hypothetical structure in C2/c. Unlabeled atoms are symmetry created (for C and N atoms: by inversion at the center of the ethyl­ene C—C-bond).
See this image and copyright information in PMC

References

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    1. Curtius, T. (1890). Ber. Deutsch. Chem. Ges. zu Berlin, 23(2), 3023–3033.
    1. Curtius, T. (1894). J. Prakt. Chem.50, 275–294.

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