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1,1‐Diaminobenzalazine has been recently reported to catalyze different types of Michael addition reactions; this organic molecule has unique characteristic features for bifunctional organocatalysis. Organocatalysts were shown to be useful in different aldol/cyclization cascade reactions, it is important to establish whether 1,1‐diaminobenzalazine can be employed in the aldol/cyclization cascade reactions. In this work, the synthesis of oxazolines with the help of organocatalyst, 1,1‐diaminobenzalazine, has been reported. This method is relatively more efficient, cost‐effective, and environmentally safe as it avoids the use of metal oxides as co‐catalysts. [ABSTRACT FROM AUTHOR]

(NHC) → E coordination interactions are being explored in many chemical species, including carbones and nitreones. (NHC) → S interactions are rare, but increasing attention is being paid to the compounds containing such interactions. The electron deficiency at the S centre is responsible for triggering electron donation from the NHC unit in (NHC) → SR(+) systems. It is well known that the positive charge at the sulfur centre increases upon single oxidation and further increases upon double oxidation. This implies that (NHC) → S interactions may become explicit after S-oxidation in the (NHC) → SR(+) systems. To explore this hypothesis, we performed quantum chemical design and synthesis of (NHC) → SR(+), (NHC) → S(O)R(+), and (NHC) → S(O)2R(+) complexes in which the ligands are imidazol-2-ylidene derivatives. Eight derivatives of the (imidazol-2-ylidene) → SR(+) systems were generated, and their sulfoxide and sulfone derivatives were obtained by oxidation using urea–H2O2 and mCPBA, respectively. The crystal structures of three compounds belonging to a series were determined. A comparison of the geometric, energetic and electronic characteristics confirmed the hypothesis that the (NHC) → S coordination interaction becomes comparatively stronger with an increase in oxygen atoms at the sulfur centre. [ABSTRACT FROM AUTHOR]

This study focuses on the systematic exploration of the emodepside conformations bound to monovalent K+ ion using quantum mechanical density functional theory (DFT) calculations at the M06‐2X/6‐31+G(d,p) level of theory. Nine conformers of emodepside and their complexes with K+ ion were characterized as stationary points on the potential energy surface. The conformational isomers were examined for their 3D structures, bonding, energetics, and interactions with the cation. A cavitand‐like structure (CC) is identified to be the energetically most stable arrangement. To arrive at a better understanding of the K+ ion binding, calculations were initially performed on complexes formed by the K+ and Na+ ions with model ligands (methyl ester and N,N‐dimethyl acetamide). Both the natural bond orbital (NBO) method and the block‐localized wavefunction (BLW) energy decomposition approach was employed to assess the bonding and energetic contributions stabilizing the ion‐bound model complexes. Finally, the solvent effect was evaluated through complete geometry optimizations and energy minimizations for the model ion‐ligand complexes and the emodepside‐K+ bound complexes using an implicit solvent model mimicking water and DMSO. [ABSTRACT FROM AUTHOR]

(NHC)→E coordination interactions were known where NHC is an N‐heterocyclic carbene, and E is a main group element (B, C, N, Si, P). Recently, it was suggested that compounds with (NHC)→S coordination chemistry are also possible. This work reports quantum chemical analysis and synthesis of (NHC)→S‐R(+) complexes in which benzothiazol‐2‐ylidene acts as a ligand. A Density functional study established that (NHC)→S interaction can best be described as a coordination interaction. Synthetic efforts were made, initially, to generate divalent sulfur compounds containing benzothiazole substituents. N‐alkylation of the heterocyclic ring in these sulfides using methyl triflate led to the generation of the desired products with (NHC)→S coordination chemistry, which involves the in situ generation of NHC ring ligands. The observed changes in the 13C NMR spectra, before and after methylation, confirmed the change in the electronic character of the C−S bond from a covalent character to a coordination character. [ABSTRACT FROM AUTHOR]