Study of the structure of besulpamide, 1‐[(4‐chloro‐3‐sulfamoylbenzoyl)amino]2,4,6‐trimethylpyridinium hydroxide inner salt, and related compounds, using X‐Ray crystallography and 1 H and 13 C nuclear magnetic resonance spectroscopy

The diuretic and antihypertensive drug Besulpamide, 1‐[(4‐Chloro‐3‐sulfamoylbenzoyl)amino]‐2,4,6‐trimethylpyridinium hydroxide inner salt, and related compounds have been investigated by nmr spectroscopy and mass spectrometry. A mechanism for the formation of the salt 5 is proposed. The tautomerism of hydroxy derivatives of Besulpamide is discussed on the basis of nmr spectroscopy. The single‐crystal X‐ray investigation of Besulpamide, R = 0.038 (R w = 0.041), showed two crystallographically independent molecular conformations in the crystal structure, space group P \documentclass{article}\pagestyle{empty}\begin{document}$\bar 1$\end{document} , a = 8.485(3), b = 14.282(2), c = 15.312(6), α = 69.41(2), β = 82.22(4), γ = 72.78(3).