engleski

Chemistry of torasemide. Molecular and crystal structure of new polymorph N

It is known from literature that torasemide, generic name for N-1 isopropyl-N-3-[4-(3-methylphenylamino)-3-pyridylsulphonyl]urea can have two polymorphic forms, denoted as T-I and T-II. A novel, third polymorph N of torasemide, T-N has been discovered and fully characterised. It crystallises in the centrosymmetric monoclinic space group P2(1)/c with two crystallographically independent molecules, which differ primarily in their different phenyl ring and N-1-isopropyl side chain orientations. Both independent molecules, i.e. conformations, can adopt a zwitter-ionic structure. The new polymorph of torasemide is characterised by a considerably complex three-dimensional hydrogen-bonding network that spans all over the crystal unit cell. The crystal packing of T-N is rather crowded, dense and compact. It is pointed out that the degree of crystal structure diversity of the existing torasemide polymorphs is considerably high, with different conformational properties of distinct torasemide molecules in its asymmetric unit.

torasemide; pyridylsulphonylurea; polymorphism; X-ray diffraction; conformation

nije evidentirano