Resumen

LEON-NEGRETE, Ariana et al. Six-Membered Heterocyclic Boronate Esters. Synthesis and Structural Analysis. J. Mex. Chem. Soc [online]. 2022, vol.66, n.4, pp.421-432.  Epub 10-Abr-2023. ISSN 1870-249X.  https://doi.org/10.29356/jmcs.v66i4.1718.

Nine heterocyclic zwitterionic boronate esters derived from carbonylphenylboronic acids and amino-diols are described. Compounds were prepared by direct condensation reaction between 3- or 4-formyl/acetylphenylboronic acids with 2-amino-2-methyl-1,3-propanediol (1a-1d) or serinol (2-amino-1,3-propanediol) (1e-1h). Compound 2e was obtained by reaction between 4-formylphenylboronic acid and serinol using a solvent mixture methanol/acetone, an aldol condensation reaction was observed. All compounds were characterized by common spectroscopic techniques such as FT-IR, mass spectrometry, and multinuclear 1H, 13C and 11B NMR spectroscopy. 11B NMR spectra showed signals between δ = 1.9 to 7.3 ppm for all compounds, indicating a tetracoordinated environment for the boron atoms in solution. X-ray diffraction analysis showed that boronates are contained in six-membered heterocycles, which have a chair conformation with -OH and -NH3 + substituents in syn disposition. The formation of channels in the crystal lattice that are filled with water and supported by hydrogen bonding interactions is noteworthy.

Palabras llave : Arylboronic acids; zwitterionic species; boronate esters; hydrogen bonds; crystallographic analysis.