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The use of the di-(p-anisyl)methyl (DAM) group at N1 of 1,4-benzodiazepin-2-ones and 1,4-benzodiazepine-2,5-diones derived from enantiopure proteinogenic amino acids has allowed retentive replacement of the C3-proton through a deprotonation/trapping protocol. The DAM group is easily removed by acidic hydrolysis following the retentive substitution process, which allows the subsequent installation of diverse N1 functionality.

Multiple X-ray crystallography and H NMR spectroscopy reveal that the acyclic conformation, including antiperiplanar orientation of the geminal and vicinal hydrogens in their preferred conformations are strongly affected by 2, 6-disubstituted aryl groups. The results would prove useful for deducing the conformational preference of related acyclic molecules, and for conformational design of new hydrocarbon backbones.

The binding of the Huperzine A within the gorge of acetylcholinesterase in a bivalent way is described. It is concluded that this binding provides new insights into factors affecting protein-ligand complementarity within the gorge.

BACKGROUND Varroa destructor is among the greatest threats to honey bee health worldwide. Acaricides used to control Varroa are becoming increasingly ineffective due to resistance issues, prompting the need for new compounds that can be used for control purposes. Ideally, such compounds would exhibit high toxicity to Varroa while maintaining relatively low toxicity to bees and beekeepers. We characterized the lethal concentrations (LC50) of amitraz, matrine, FlyNap®, the experimental carbamates 2‐((2‐ethylbutyl)thio)phenyl methylcarbamate (1) and 2‐(2‐ethylbutoxy)phenyl methylcarbamate (2), and dimethoate (positive control) for Varroa using a glass vial assay. The test compounds also were applied to honey bees using an acute contact toxicity assay to determine the adult bee LD50 for each compound. RESULTS: Amitraz was the most toxic compound to Varroa, but carbamate 2 was nearly as active (within 2‐fold) and the most selective due to its lower bee toxicity, demonstrating its promise as a Varroa control. While carbamate 1 was less toxic to honey bees than was amitraz, it was also 4.7‐fold less toxic to the mites. Both matrine and FlyNap® were relatively ineffective at killing Varroa and were moderately toxic to honey bees. CONCLUSION: Additional testing is required to determine if carbamate 2 can be used as an effective Varroa control. As new chemical treatments are identified, it will be necessary to determine how they can be utilized best alongside other control techniques as part of an integrated pest management program. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Research has been conducted on tryptophan regioisomers. The catalytic asymmetric syntheses of these regioisomers have been carried out in expanding the tryptophan-like amino acid toolbox and the details are reported.

Research has been conducted on the lithiated nitriles. The structure of the lithiated phenylacetonitrile has been investigated and the position of aggregation state and metalation has been established via X-ray crystallography and via (super)6 Li- (super)15 N scalar coupling.

THF and HMPA-THF solution was used to study the structures of lithiated phenylacetonitrile and 1-naphthylacetonitrile.

Studies have been undertaken to further optimize and define the structural limitations of the nitrile aldol reaction. Lithaited phenylacetronitrile showed diastereoselectivity for addition to benzaldehyde. Secondary aldehydes yielded reasonable amounts of recrystallized anti-aldols at 0.1 M concentrations, and pivalaldehyde showed good results at up to 0.3 M concentrations. Aldol diastereoselectivity of aliphatic nitriles was found not to be uniformly anti-selective.

The Aldol reactions of seven benzylic nitriles and four aldehydes were examined. The results showed that the benzylic nitriles undergo anti-selective aldol reaction. Aldehydes with bulky secondary or tertiary substituents exhibited good to excellent stereoselectivities. The formed aldols were used to prepare the corresponding gamma-amino alcohols, which are being evaluated for antidepressant properties.

Electronic and steric factors regulated regioselectivity during sulfonation of leuco xanthene dyes. Sulfonation improved water solubility of inorganic substrates in single- and multiphase aqueous chemical systems to enhance performance. Sulfonated xanthene dyes improved color correction in color instant integral film products.

A unique sulfonated enedione exhibiting spectroscopic and chemical properties inconsistent with a hydroquinone has been discovered. The enedione has a strong C=O stretch at 16,90 cm(super -1), lacks an O-H stretch and does not react towards NaOCl. Nuclear magnetic resonance spectroscopy indicates a 2,6-substitution of the phenyl and tosyl groups in the starting enedione.

NMR spectra and HPLC studies of the stereoselective and regioselective addition of a nitrile anion to aldehydes reveals that the reaction involves an intermediate that is a ketenimine-like N-lithiated-nitrile anion. Concentration studies optimize the reaction between benzaldehyde and lithiated phenylacetonitrile.

Glycine-derived 1H-benzo[e][1,4]diazepin-2(3H)-ones (BZDs) featuring C9- and N1-substitution has displayed enantiomerization barriers too high to be measured by [super 1]H NMR coalescence experiments. The studies have shown the highest enantiomerization barriers ever determined for a BZD.

Computational studies on ion-pair separation (IPS) of THF-solvated fluorenyl, diphenylmethyl, and trityl lithium is are presented. The detailed study results provide insight into energy equilibrium geometries, enthalpies, and exothermicity of IPS.

Enantiopure amino-acid derived 1H-benzo[e][1,4]diazepin-2(3H)-ones (BZDs) have undergone highly retentive deprotonation/alkylation reactions and a new alanine-derived BZD is prepared for determining their stereochemical course. Minimization of torsional effects at the BZD ring fusion and maximization of imine and amide resonance are described that are in favor of concave-face alkylation.