{'fraction_non_alphanumeric': 0.041474654377880185, 'fraction_numerical': 0.014483212639894667, 'mean_word_length': 5.608695652173913, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Ab Initio and DFT Conformational Studies of Propanal, 2-Butanone, and Analogous Imines and Enamines.

The potential energy surfaces (PES) of 2-butanone, 2-butanimine, 1-butenamine, propanal, and propanimine have been explored with ab initio and DFT calculations at the RHF/6-311G**, MP2/6-311G**, and B3LYP/6-311G** levels of theory. In agreement with previous experimental and computational results, the PES provides two minima for each of the above molecules with the exception of 2-butanone, which clearly shows three distinct minima. Factors influencing the conformational preferences are also elaborated. Our calculations suggest that for 2-butanone and propanal, the steric and the bond dipole interactions are primarily responsible for the conformational preferences of these compounds. Additional charge-charge interactions might also play an important role in determining the imine conformations. For enamines, however, steric interactions play a critical role, with bond dipole interactions exerting some influence. Our results also suggest that for imine formation from butanone and/or propanal, the imine is the predominant product, not the enamine, which is consistent with experimental observations. Therefore, these calculations should provide a better understanding of the ketone/aldehyde to imine and enamine transformations. This transformation may introduce an important imine moiety for the analogues of trans-N-methyl-4-(1-naphthylvinyl)pyridine (NVP), a choline acetyltransferase (ChAT) inhibitor.