Vicinal difluorination as a C=C surrogate: an analog of piperine with enhanced solubility, photostability, and acetylcholinesterase inhibitory activity

• Yuvixza Lizarme-Salas,
• Alexandra Daryl Ariawan,
• Ranjala Ratnayake,
• Hendrik Luesch,
• Angela Finch and
• Luke Hunter

Beilstein J. Org. Chem. 2020, 16, 2663–2670, doi:10.3762/bjoc.16.216

• feature of structures 2a,b (Figure 2) is that both, the α-fluorine and the β-fluorine atoms of each structure make close contacts with the hydrogen atoms on the piperidine ring (2.08–2.34 Å). This manifests in the observation of a through-space coupling (J = 1.9 Hz) between the α-fluorine and a piperidine

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• : DFT; F···H hydrogen bond; fluorinated phenylcoumarin; Pechmann reaction; through-space coupling; Introduction Coumarins constitute one of the big classes of naturally occurring compounds. The first coumarin was isolated from the tonka bean (Dipteryx odorata) in 1820 and, to date, more than 1300

• ). Examples of through-space coupling between fluorine and hydrogen atoms in organic molecules are reported in the chemical literature [46][47], with magnitudes as large as 7 Hz for 7JHF [46] One report of TS-coupling between F and H atoms comments that “...it appears that significant coupling only occurs