Crystal structures of substituted imidazolidine derivatives

The crystal structures of isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]methyl-5-phenyl-,N-oxide] (C13H13N5O3) (I), isoxazole,3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(4-methylphenyl)-,N-oxide] (C14H15N5O3) (II) and isoxazole, 3-[[dihydro-2-[(Z)-2-oxohyrazono]-1H-imidazol-1-(3H)-yl]-methyl-5-(2-methoxyphenyl)-,N-oxide] (C14H15N5O4) (III) have been determined by X-ray diffraction studies. The compound I, crystallized in triclinic space group P(1) over bar with unit cell dimensions a = 7.2405(7) angstrom, b = 7.9936(8) angstrom, c = 11.6573(11) angstrom, alpha = 97.801(2)degrees, beta = 90.884(2)degrees, gamma = 96.250(2)degrees and Z = 2. Compound II crystallized in orthorhombic space group Pna2(1) with unit cell dimensions a = 10.1778(10) angstrom, b = 28.228(3) angstrom, c = 5.1206(5) angstrom, and Z = 4. Compound III crystallized in monoclinic space group P2(1)/n with unit cell dimensions a = 7.8439(9) angstrom, b = 7.8544(9) angstrom, c = 23.534(3) angstrom, beta = 99.464(2)degrees and Z = 4. For all three compounds, the five-membered imidazolidine ring adopts an envelope conformation. The crystal structures are stabilized by both the intramolecular N-H center dot center dot center dot O and intermolecular N-H center dot center dot center dot N hydrogen bonding.