Distinct Molecular Structures and Hydrogen Bond Patterns of a, a-diethyl-substituted Cyclic Imide, Lactam, and Acetamide-derivatives in the Crystalline Phase




Krivoshein, Arcadius

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Journal of Molecular Structure


α,α-Dialkyl- and α-alkyl-α-aryl-substituted cyclic imides, lactams, and acetamides show promising anticonvulsant, anxiolytic, and anesthetic activities. While a number of crystal structures of various α-substituted cyclic imides, lactams, and acetamides were reported, no in-depth comparison of crystal structures and solid-state properties of structurally matched compounds have been carried out so far. In this paper, we report molecular structure and intermolecular interactions of three α,α-diethyl-substituted compounds – 3,3-diethylpyrrolidine-2,5-dione, 3,3-diethylpyrrolidin-2-one, and 2,2-diethylacetamide – in the crystalline phase, as studied using single-crystal X-ray diffraction and IR spectroscopy. We found considerable differences in the patterns of H-bonding and packing of the molecules in crystals. These differences correlate with the compounds’ melting points and are of significance to physical pharmacy and formulation development of neuroactive drugs.



Cyclic imides Lactams Acetamides Antiepileptic X-Ray diffraction IR spectroscopy


3. Krivoshein, A. V., Ordonez, C., Khrustalev, V. N., and Timofeeva, T. V. (2016) Distinct molecular structures and hydrogen bond patterns of a,a-diethyl-substituted cyclic imide, lactam, and acetamide derivatives in the crystalline phase, Journal of Molecular Structure, 1121, 196-202.