These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: A 2:1 sulfamethazine-theophylline cocrystal exhibiting two tautomers of sulfamethazine.
    Author: Lu J, Cruz-Cabeza AJ, Rohani S, Jennings MC.
    Journal: Acta Crystallogr C; 2011 Aug; 67(Pt 8):o306-9. PubMed ID: 21817798.
    Abstract:
    In the title cocrystal, 4-amino-N-(4,6-dimethylpyrimidin-2-yl)benzenesulfonamide-4-amino-N-(4,6-dimethyl-1,2-dihydropyrimidin-2-ylidene)benzenesulfonamide-1,3-dimethyl-7H-purine-2,6-dione (1/1/1), C(7)H(8)N(4)O(2)·2C(12)H(14)N(4)O(2)S, two sulfamethazine molecules cocrystallize with a single molecule of theophylline. Each molecule of sulfamethazine forms a hydrogen-bonded ribbon along the b axis crosslinked by further hydrogen bonding. The two sulfamethazine molecules exhibit a hydrogen-shift isomerization so that the crystal structure contains both tautomeric forms. Calculation of their relative energies showed that the tautomer protonated at the chain N atom is considerably more stable than the one where an N atom in the aromatic ring is protonated. The latter, here observed for the first time, is stabilized through strong intermolecular interactions with the theophylline molecules.
    [Abstract] [Full Text] [Related] [New Search]