Synthesis and conformational analysis of pyran inter-halide analogues of ᴅ-talose

• Olivier Lessard,
• Mathilde Grosset-Magagne,
• Paul A. Johnson and
• Denis Giguère

Beilstein J. Org. Chem. 2024, 20, 2442–2454, doi:10.3762/bjoc.20.208

• orbitals. Keywords: organofluorine; pyran inter-halide; solid-state conformation; solution-state conformation; Introduction Polyfluorinated pyran analogues of carbohydrates have attracted attention over the years. This class of glycomimetics has great biological potential with useful applications [1][2

• ][25][26][27][28][29][30], such as the solution-state conformation of diastereomeric polyfluorohexitols [31]. Herein, we report the synthesis of pyran inter-halide analogues of ᴅ-talopyranose 6, integrating also the 2,3-cis, 3,4-cis relationship for the halogens, from known intermediate 5 (Figure 1b

Inversion symmetry and local vs. dispersive interactions in the nucleation of hydrogen bonded cyclic n-mer and tape of imidazolecarboxamidines

• Sihui Long,
• Venkatraj Muthusamy,
• Peter G. Willis,
• Sean Parkin and
• Arthur Cammers

Beilstein J. Org. Chem. 2008, 4, No. 23, doi:10.3762/bjoc.4.23

• high densities of 9b1–9b3 and the low, per molecule, gas-phase energies, and the low-energy θ parameters. From these observations we make the following hypothesis. The solution states of 9b did not completely desolvate during the nucleation process thereby maintaining near solution-state conformation

• . This allowed the low calculated energies, and allowed the low-energy θ parameters. Disordered solvent molecules in the crystalline phase of 9 occupied voids at the faces of the two hydrogen-bound imidazole rings thereby increasing the densities of 9 and preserving near solution-state conformation for

• hydrogen bonds like those in Figure 6 for tetramer 9a, over the less linear hydrogen bonds in 5c and 11a in Figure 5 and Figure 7 [14][15][16]. Figure 11 also supports the hypothesis that inter-dimer dispersive forces edited the optimum solution state conformation and n-mer molecularity. The low-energy Ci

The vicinal difluoro motif: The synthesis and conformation of erythro- and threo- diastereoisomers of 1,2-difluorodiphenylethanes, 2,3-difluorosuccinic acids and their derivatives

• David O'Hagan,
• Henry S. Rzepa,
• Martin Schüler and
• Alexandra M. Z. Slawin

Beilstein J. Org. Chem. 2006, 2, No. 19, doi:10.1186/1860-5397-2-19

• erythro- and threo- 2,3-difluorosuccinic acids were then prepared. The solid and solution state conformation of these compounds was assessed by X-ray crystallography and NMR. Ab initio calculations were also carried out to model the conformation of erythro- and threo- 1,2-difluoro-1,2-diphenylethane as

• of the phenyl group to act as a latent carboxylic acid [17]. This paper describes these studies and we report the solid and solution state conformation of the erythro- and threo- diastereoisomers of 13 and the resultant 2,3-difluorosuccinic acid stereoisomers and some of their derivatives. Some of