Abstract
The structure of zymonic acid (systematic name: 4-hydroxy-2-methyl-5-oxo-2,5-dihydrofuran-2-carboxylic acid), C6H6O5, which had previously eluded crystallographic determination, is presented here for the first time. It forms by intramolecular condensation of parapyruvic acid, which is the product of aldol condensation of pyruvic acid. A redetermination of the crystal structure of pyruvic acid (systematic name: 2-oxopropanoic acid), C3H4O3, at low temperature (90 K) and with increased precision, is also presented [for the previous structure, see: Harata et al. (1977). Acta Cryst. B33, 210–212]. In zymonic acid, the hydroxylactone ring is close to planar (r.m.s. deviation = 0.0108 Å) and the dihedral angle between the ring and the plane formed by the bonds of the methyl and carboxylic acid carbon atoms to the ring is 88.68 (7)°. The torsion angle of the carboxylic acid group relative to the ring is 12.04 (16)°. The pyruvic acid molecule is almost planar, having a dihedral angle between the carboxylic acid and methyl-ketone groups of 3.95 (6)°. Intermolecular interactions in both crystal structures are dominated by hydrogen bonding. The common R22(8) hydrogen-bonding motif links carboxylic acid groups on adjacent molecules in both structures. In zymonic acid, this results in dimers about a crystallographic twofold of space group C2/c, which forces the carboxylic acid group to be disordered exactly 50:50, which scrambles the carbonyl and hydroxyl groups and gives an apparent equalization of the C—O bond lengths [1.2568 (16) and 1.2602 (16) Å]. The other hydrogen bonds in zymonic acid (O—HO and weak C—HO), link molecules across a 21-screw axis, and generate an R22(9) motif. These hydrogen-bonding interactions propagate to form extended pleated sheets in the ab plane. Stacking of these zigzag sheets along c involves only van der Waals contacts. In pyruvic acid, inversion-related molecules are linked into R22(8) dimers, with van der Waals interactions between dimers as the only other intermolecular contacts.
Document Type
Article
Publication Date
6-2019
Digital Object Identifier (DOI)
https://doi.org/10.1107/S2056989019007072
Funding Information
We are thankful for research funding from the National Science Foundation under NSF CAREER award CHE-1255290 to MIG, and the MRI program, grants CHE-0319176 and CHE-1625732. An International Visiting Scholar grant from the College of Arts and Sciences at UK is gratefully acknowledged.
Related Content
Crystal structure: contains datablocks global, pyruvic, zymonic. DOI: https://doi.org//10.1107/S2056989019007072/hb7818sup1.cif
Structure factors: contains datablock zymonic. DOI: https://doi.org//10.1107/S2056989019007072/hb7818zymonicsup2.hkl
Structure factors: contains datablock pyruvic. DOI: https://doi.org//10.1107/S2056989019007072/hb7818pyruvicsup3.hkl
Supporting information file. DOI: https://doi.org//10.1107/S2056989019007072/hb7818zymonicsup4.cml
Supporting information file. DOI: https://doi.org//10.1107/S2056989019007072/hb7818pyruvicsup5.cml
Supplementary crystallographic information is available on the online version of the article.
Repository Citation
Heger, Dominik; Eugene, Alexis J.; Parkin, Sean R.; and Guzman, Marcelo I., "Crystal Structure of Zymonic Acid and a Redetermination of Its Precursor, Pyruvic Acid" (2019). Chemistry Faculty Publications. 147.
https://uknowledge.uky.edu/chemistry_facpub/147
Crystallographic Information File (CIF). Contains datablocks global, pyruvic, zymonic.
sendsupfiles1.txt (128 kB)
Structure factor file (CIF format). Contains datablock zymonic.
sendsupfiles2.txt (115 kB)
Structure factor file (CIF format). Contains datablock pyruvic.
sendsupfiles3 (2 kB)
Chemical Markup Language (CML) file. Supplementary material.
sendsupfiles4 (1 kB)
Chemical Markup Language (CML) file. Supplementary material.
Included in
Diagnosis Commons, Environmental Chemistry Commons, Food Chemistry Commons, Investigative Techniques Commons, Laboratory and Basic Science Research Commons, Organic Chemicals Commons, Organic Chemistry Commons, Physical Chemistry Commons
Notes/Citation Information
Published in Acta Crystallographica Section E: Crystallographic Communications, v. 75, part 6, p. 858-862.
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.