Structure–Retention Relationship in a Series of Chiral 1,4-Disubstituted Piperazine Derivatives on Carbohydrate Chiral Stationary Phases

Tf2O-Promoted Intramolecular Schmidt Reaction of the ω-Azido Carboxylic Acids

“…Therefore, further protection of 2a with acetic anhydride was applied for better purification of the product. The amide 3a was obtained with 80% yield for two steps, and the 1 H NMR and 13 C NMR of 3a were congruent with those previously reported. 6 If more Tf 2 O (4.0 equiv) was used, triflamide 4a would be delivered with 64% yield, whose structure was confirmed by X-ray analysis.…”

“…Purification of the synthetic compounds by flash column chromatog-raphy employed neutral silica gel (200−300 mesh or 300−400 mesh), which was purchased from Qingdao Haiyang Chemical Co. Ltd. The NMR spectra were recorded on a Bruker 400 MHz spectrometer, and tetramethylsilane (δ = 0 and δ = 7.26) was used as an internal standard for 1 H NMR (400 MHz) and CDCl 3 (δ = 77.16) for 13 C NMR(100 MHz). 13 C NMR was performed with the APT [methyl and methine (down), methylene and quaternary carbon (up)].…”

“…The NMR spectra were recorded on a Bruker 400 MHz spectrometer, and tetramethylsilane (δ = 0 and δ = 7.26) was used as an internal standard for 1 H NMR (400 MHz) and CDCl 3 (δ = 77.16) for 13 C NMR(100 MHz). 13 C NMR was performed with the APT [methyl and methine (down), methylene and quaternary carbon (up)]. The IR spectra were recorded on a Perkin Elmer spectrometer with a potassium bromide crystal optic rectangle.…”

Synthesis of 6‐Fluoro‐7‐cyclic Amino‐substituted Dicarboxylic Acid Quinolones and their Antibacterial Activity

“…θ‐Phenylene diamine is reacted with ethyl‐piperidine‐4‐carboxylic acid in refluxing HCl solution furnished 2‐(piperidin‐4‐yl)‐1 H ‐benzo[ d ] imidazole . 2‐(Piperazin‐1‐yl)pyrimidine was prepared from the condensation of 2‐chloropyrimidine and piperazine , and 2‐(piperazin‐1‐yl) ethanol was obtained from ethylene oxide and piperazine .…”

“…The 3D structures of selected proteins [ Escherichia coli (1XDQ), Pseudomonas aeruginosa (3R6W, 3OCN, 3OCL, 3JVV), Staphylococcus aureus (3ITP), Klebsiella pneumoniae (3GFX), Homo sapiens (3V2B,3SE2), and Notoc punctiforme (2J68), were selected from Protein Data Bank (PDB) RCSB with an X‐ray resolution in the range of 1.75 to 3.10 Å. Among the aforementioned proteins, 1XDQ and 3SE2 were screened on the basis of the fitness score.…”