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Crystal and Molecular Structures of Hydroxamic Acid Derivatives

<p align="justify">Hydroxamic acids are weak organic acids with various applications in pharmaceuticals, food additives, and extractive metallurgy.^[1-4] Their importance and applications originate primarily from their ability to form stable metal-ion binding sites.^[4] Desferrioxamine B, a tris-hydroxamic acid, and hydroxyurea and its derivatives^[5] are the most important compounds containing the hydroxamate group, due to their use in medicine (thalasaemia major, melanoma, resistant chronic myelocytic leukaemia, and recurrent, metastatic, or inoperable carcinoma of the ovary, and recently in the treatment of HIV).</p> <p align="justify">Diffracted intensities were collected on the Oxford Diffraction Xcalibur 3 diffractometer using graphite-monochromated MoK_&#945; radiation at 100 K. Data reductions were performed using the CrysAlis software package.^[6] The structures were solved by direct methods (SHELXS) and refined by the full-matrix least-squares method based on <i>F</i>² against all reflections (SHELXL).^{[7, 8]}</p> <p>Crystallographic data for the compounds 1, 2 and 3: <p>1) Monoclinic, P21/a, <i>a</i> = 7.511(12) &Aring ; ; , <i>b</i> = 11.924(17) &Aring ; ; , <i>c</i> = 8.179(12) &Aring ; ; , <i>&#946; </i> = 98.41(13)&ordm ; ; , <i>V</i> = 724.70(14) &Aring ; ; ³, <i>Z</i> = 4, <i>R</i> = 0.0313</p> <p>2) Triclinic, P-1, <i>a</i> = 7.765(21) &Aring ; ; , <i>b</i> = 12.139(33) &Aring ; ; , <i>c</i> = 12.783(31) &Aring ; ; , <i>&#945; </i> = 66.36(24)&ordm ; ; , <i>&#946; </i> = 76.78(22)&ordm ; ; , <i>&#947; </i> = 82.79(22)&ordm ; ; , <i>V</i> = 1073.77(13) &Aring ; ; ³, <i>Z</i> = 2, <i>R</i> = 0.0493</p> <p>3) Triclinic, P-1, <i>a</i> = 8.995(17) &Aring ; ; , <i>b</i> = 13.820(3) &Aring ; ; , <i>c</i> = 18.714(3) &Aring ; ; , <i>&#945; </i> = 100.76(14)&ordm ; ; , <i>&#946; </i> = 90.45(14)&ordm ; ; , <i>&#947; </i> = 107.23(16)&ordm ; ; , <i>V</i> = 2177.9(8) &Aring ; ; ³, <i>Z</i> = 4, <i>R</i> = 0.0479</p> <p>Above mentioned compounds were synthesized in the course of developing new derivatives of hydroxamic acids and hydroxyureas to evaluate their chemical and metal-binding properties. In addition, we have recently published the structure of the chloride salt of betainohydroxamic acid^[9] in order to investigate the correlation between the electronic properties of the hydroxamate substituents and the hydroxamate C&#8211; N bond length.</p> <p>[1] C. Hersko et al., J. Inorg. Biochem. 47 (1992) 267&#8211; 277.</p> <p>[2] H. J. Rogers, Iron Transport in Microbes, Plants and Animals, VCH Publishers, New York, 1987, pp. 223&#8211; 233.</p> <p>[3] A. J. Ghio et al., Am. J. Physiol. 263 (1992) 511&#8211; 518.</p> <p>[4] A. L. Crumbliss, Handbook of Microbial Iron Chelates, CRC Press, Boca Raton, 1991, pp. 177&#8211; 233.</p> <p>[5] S. J. Chung and D. H. Kim, Bioorg. Med. Chem. 9 (2001) 185&#8211; 189.</p> <p>[6] Oxford Diffraction (2003). CrysAlis CCD and CrysAlis RED. Versions 1.170.</p> <p>[7] G. M. Sheldrick, Acta Cryst. A46 (1990) 467&#8211; 473.</p> <p>[8] G. M. Sheldrick, SHELXL97 (1997) University of Göttingen, Germany.</p> <p>[9] D. Matković-Čalogović et al., Acta Cryst. C59 (2003) o694&#8211; o695.</p>

crystal and molecular structure; hydroxamic acid derivatives

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