Crystal Structure of 1,3,5-Tri(4-chlorophenyl)carbamoylurea

2001 Analytical Sciences  
As promising chelating agents for the treatment of lead and mercury poisoning in humans, 1-4 we are currently working on the synthesis of 4,5-dicarbonyl exo-heterocyclic compounds, such as 1,3-di(p-chlorophenyl)imidazolidinetrione. During the preparation of this compound, an intermediate was obtained as shiny crystals; spectroscopic data (NMR, UV and IR) suggest its structure. The structure of this reaction intermediate was determined by X-ray analysis. 1,3,5-Tri(4-chlorophenyl)carbamoylurea
more » ... yl)carbamoylurea was easily synthesized from 2.5 equivalents of p-chlorophenylisocyanate and one equivalent of oxalic bis(cyclohexylidenehydrazide) in alkaline media using anhydrous triethylamine and Li2CO3 under a nitrogen atmosphere at 70˚C for 4 h. Purification by column chromatography (hexane:ethyl acetate, 9:1 v/v) provided the product in 70% yield. Colorless crystals of the title compound were grown by slow evaporation from an acetone-hexane solution. The X-ray data for the crystals of the title compound were collected with graphite-monochromatized Mo Kα radiation at 293 K. No absorption correction was applied. The compound is sufficiently stable, and no change in the crystalline appearance was observed during X-ray exposure. The structure was solved by direct methods and refined by full-matrix leastsquares with anisotropic temperature factors for the nonhydrogens atoms. The hydrogen atoms bonded to C atoms were assigned based on the expected bonding geometry, and those bonded to N atoms were found in a difference-Fourier map. The hydrogen atoms were refined isotropically in the final leastsquares cycles with a fixed U value of 0.06 Å 2 . The software used to prepare material for publication was PARST97. 5 Table 1 summarizes the crystal and experimental data. The molecular structure is shown in Fig. 2 . The bond lengths and angles are normal and the aromatic rings are planar within the 355 Formula: C20H14O2N3Cl3 Formula weight = 434.69 Crystal system: triclinic Space group: P1 -Z = 2 a = 9.259(1)Å b = 10.865(1)Å c = 11.007(1)Å = 61.93(1)˚ = 79.93(1)˚ = 88.24(1)V = 960.2(2)Å 3 Dx = 1.503 g/cm 3 Dm = 1.502 g/cm 3 (measured by flotation) (Mo Kα) = 0.499 mm -1 T = 293 K colorless F(0 0 0) = 444 0.40 × 0.20 × 0.18 mm Radiation: Mo Kα -2 scans with 2 max = 60R = 0.046 (on I) Rw = 0.097(on I) ( / )max = 0.001 (∆ )max = 0.256 eÅ -3 (∆ )min = -0.272 eÅ -3
doi:10.2116/analsci.17.355 pmid:11990556 fatcat:3zpkump24vby3pqsag7qvfgcza