Unraveling the sequence of electron flow along the cyclocondensation reaction between ciprofloxacin and thiosemicarbazide through the bonding evolution theory

Diels-Alder Reaction of C60 and C70 Fullerenes Confined in a Nanohoop: A Theoretical Study

The reactivity of the bonds in fullerenes is crucial for their chemical modification of their structures. Recent studies demonstrate that fullerenes can be encapsulated as guest molecule in conjugated [n]cyclodibenzopentalene nanohoop, forming intriguing host-guest systems with potential applications in organic material. In this study, the influence of encapsulating C60 and C70 fullerenes in a [4] cyclodibenzopentalene nanohoop on their bond reactivity is theoretically investigated. The binding energy of the complex of nanohoop and C60 is 2.7 kcal mol-1 higher than that of the nanohoop and C70, highlighting a substantial interaction. However, the differences in bond reactivity between encapsulated and isolated C60 and C70 is relatively small, due to interaction-induced effects from the nanohoop. To understand the origin of these observations, the distortion/interaction analysis was performed . These findings provide insight into how encapsulation affects fullerene reativity and contribute to the broader understanding of weak interactions in supramolecular systems. , The present study on fullerene-nanohoop host-guest system offers new insights into intermolecular weak interactions and enhances our understanding of structural and energetic aspects of molecular recognition and self-assembly in suppramolecular chemistry.

Identification of Potential Inhibitors of Plasmodium falciparum L-lactate Dehydrogenase From Selected African Compound Libraries: Virtual Screening, Molecular Mechanics-Generalized Born Surface Area, and Molecular Dynamics Studies

We evaluated 4,512 natural products from natural product library from Central African medicinal plants for drug discovery and South African natural compounds database libraries for the identification of potential Plasmodium falciparum L-lactate dehydrogenase inhibitors considering the virtual screening process. Extra precision virtual screening enabled the ranking of the top hundred hit molecules based on their docking properties. The selected hits were further shortened based on docking and molecular mechanics-generalized born surface area parameters in comparison with the reference. As a result, four hits were chosen: Mol1, Mol2, Mol3, and Mol4, all of them from the chalcone and quinone families. These molecules showed good predicted absorption, distribution, metabolism, and excretion, and toxicity properties. Finally, the molecular dynamics simulation results showed that the three chalcones, Mol1-4, formed an H-bond, hydrophobic interaction with key amino acids in the active site. This in silico study suggests that the chalcone compounds could serve as a potential source for developing new effective antimalarial drugs to combat malaria. Further in vitro or in vivo studies might be conducted to determine their actual effectiveness.

Decoding the reaction mechanism of the cyclocondensation of ethyl acetate2-oxo-2-(4-oxo-4H-pyrido [1.2-a] pyrimidin-3-yl) polyazaheterocycle and ethylenediamine using bond evolution theory

We investigated the flow of electron density along the cyclocondensation reaction between ethyl acetate 2-oxo-2-(4-oxo-4H-pyrido[1.2-a]pyrimidin-3-yl) polyazaheterocycle (1) and ethylenediamine (2) at the ωB97XD/6-311++G(d,p)computational method within of bond evolution theory (BET). The exploration of potential energy surface shows that this reaction has three channels (1-3) with the formation of product 3 via channel-2 (the most favorable one) as the main product and this is in good agreement with experimental observations. The BET analysis allows identifying unambiguously the main chemical events happening along channel-2. The mechanism along first step (TS2-a) is described by a series of four structural stability domains (SSDs), while five SSDs for the last two steps (TS2-b and TS2-c). The first and third steps can be summarized as follows, the formation of N1-C6 bond (SSD-II), then, the restoration of the nitrogen N1 lone pair (SSD-III), and finally, the formation of the last O1-H1 bond (SSD-IV). For the second step, the formation of hydroxide ion is noted, as a result of the disappearance of V(C6,O7) basin and the transformation of C6-N1 single bond into double one (SSD-IV). Finally, the appearance of V(O7,H2) basin lead to the elimination of water molecule within the last domain is observed.