Abstract
The crystal structures of (E)-1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-benzyl-oxime, C12H12N4O3, (I), (E)-1-methyl-5-nitro-1H-imidazole-2-carb-alde-hyde O-(4-fluoro-benz-yl) oxime, C12H11FN4O3, (II), and (E)-1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-(4-bromo-benz-yl) oxime, C12H11BrN4O3, (III), are described. The dihedral angle between the ring systems in (I) is 49.66 (5)° and the linking Nm-C-C=N (m = methyl-ated) bond shows an anti conformation [torsion angle = 175.00 (15)°]. Compounds (II) and (III) are isostructural [dihedral angle between the aromatic rings = 8.31 (5)° in (II) and 5.34 (15)° in (III)] and differ from (I) in showing a near-syn conformation for the Nm-C-C=N linker [torsion angles for (II) and (III) = 17.64 (18) and 8.7 (5)°, respectively], which allows for the occurrence of a short intra-molecular C-H⋯N contact. In the crystal of (I), C-H⋯N hydrogen bonds link the mol-ecules into [010] chains, which are cross-linked by very weak C-H⋯O bonds into (100) sheets. Weak aromatic π-π stacking inter-actions occur between the sheets. The extended structures of (II) and (III) feature several C-H⋯N and C-H⋯O hydrogen bonds, which link the mol-ecules into three-dimensional networks, which are consolidated by aromatic π-π stacking inter-actions. Conformational energy calculations and Hirshfeld fingerprint analyses for (I), (II) and (III) are presented and discussed.
Highlights
The crystal structures of (E)-1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-benzyloxime, C12H12N4O3, (I), (E)-1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-(4-fluorobenzyl) oxime, C12H11FN4O3, (II), and (E)-1-methyl-5nitro-1H-imidazole-2-carbaldehyde O-(4-bromobenzyl) oxime, C12H11BrN4O3, (III), are described
In the crystal of (I), C—HÁ Á ÁN hydrogen bonds link the molecules into [010] chains, which are cross-linked by very weak C—HÁ Á ÁO bonds into (100) sheets
We report the crystal structures, Hirshfeld surface analyses and conformational energy calculations for three compounds from that study, viz. (E)-1methyl-5-nitro-1H-imidazole-2-carbaldehyde O-benzyloxime, C12H12N4O3 (I), (E)-1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-(4-fluorobenzyl) oxime C12H11FN4O3 (II) and (E)1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-(4-bromobenzyl) oxime, C12H11BrN4O3 (III)
Summary
Trypanosomes infect a variety of hosts and cause various serious illnesses, including sleeping sickness (transmitted by Trypanosoma brucei) and Chagas’ disease. New effective drugs are urgently required for the treatment of Chagas’ disease, which infects an estimated 6.6 million people worldwide (Rassi et al, 2010): benznidazole and nifurtimox have been the only recognised treatments for over 40 years and both drugs present variable results and undesirable side effects (Soeiro & Castro, 2011). While active, has serious side effects (Poli et al 2002). We have recently described (Carvalho et al, 2017) the syntheses and biological activities of a family of 5-nitroimidazolyl-O-benzyloxime ethers, which displayed moderate. We report the crystal structures, Hirshfeld surface analyses and conformational energy calculations for three compounds from that study, viz. (E)-1methyl-5-nitro-1H-imidazole-2-carbaldehyde O-benzyloxime, C12H12N4O3 (I), (E)-1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-(4-fluorobenzyl) oxime C12H11FN4O3 (II) and (E)1-methyl-5-nitro-1H-imidazole-2-carbaldehyde O-(4-bromobenzyl) oxime, C12H11BrN4O3 (III)
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