Azole. 44

The structure analyses of racemic 3-chloro-1-(4-morpholino-5-nitroimidazol-1-yl)propan-2-ol, C 1 0H 1 5CIN 4 O 4 , (II), and 3-chloro-1-(5-morpholino-4-nitroimidazol-1-yl)propan-2-ol, C 1 0H 1 5CIN 4 O 4 , (III), have been undertaken in order to determine the position of the morpholine residue in these two isomers. The morphine residue in (II) is connected at the 4-position, while in (III), it is connected at the 5-position of the imidazole ring. The morpholine mean planes and nitro groups in the two compounds deviate from the imidazole planes to different extents. The nitro groups in (II) and (III) take part in the conjugation system of the imidazole rings. In consequence, the exocyclic C−N bonds are significantly shorter than the normal single Csp 2 −NO 2 bond and the nitro groups in (II) and (III) show an extraordinary stability on treatment with morpholine and piperidine [Gzella, Wrzeciono & Pοppel (1999). Acta Cryst. C55, 1562-1565]. In the crystal lattice, the molecules of both compounds are linked by O−H...N and C−H...O intermolecular hydrogen bonds.