Acta Cryst. (2001). E57, o1179-o1182  [ doi:10.1107/S1600536801018657 ]

Hydrogen bonding patterns in trimethoprim sulfate trihydrate [trimethoprim = 2,4-diamino-5-(3,4,5-methoxybenzyl)pyrimidine]

P. T. Muthiah, B. Umadevi, N. Stanley, X. Shui and D. S. Eggleston

Abstract: Trimethoprim sulfate trihydrate, 2C₁₄H₁₉N₄O₃⁺·SO₄^2-·3H₂O [(TMPH⁺)₂(SO₄)^2-·3H₂O, TMPH⁺ = 2,4-diamino-5-(3,4,5-methoxybenzyl)pyrimidin-1-ium], is an antibacterial agent. In its N1-protonated form, it inhibits the bacterial dihydrofolate reductase enzyme. The asymmetric unit contains two TMPH cations, a sulfate anion and three water molecules. The TMPH cations are each paired about their respective inversion centres via N-HN hydrogen bonds. These pairs are further bridged by a network of hydrogen bonds involving the sulfate anion and water molecules. Both the TMPH cations make hydrogen bonds with water molecules through the 2-amino groups, reminiscent of TMP-dihydrofolate reductase complexes. The pyrimidine plane makes a dihedral angle of 75.89  (8)° with the phenyl ring in one TMPH cation, the corresponding angle in the other moiety being 69.96  (8)°.

Online 17 November 2001

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