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Chemistry of the phenoxathiins and isosterically related heterocycles. XXX. The crystal and molecular structure of 2-AZA-phenoxathiin 2-oxide: Further evidence in support of the relationship between the 13C-NMR chemical shift of C-10a resonance and the molecular dihedral angle |
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| Authors: | S R Caldwell J C Turley G E Martin C A Dwiggins M B Hossain J V Mendenhall D Van Der Helm |
| Institution: | 1. Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Houston, Houston, Texas 77004;2. Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Houston, Houston, Texas 77004
G. E. Martin, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Houston, Houston, Texas 77004 D. Van Der Helm, Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73019;3. Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73019;4. Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73019 G. E. Martin, Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Houston, Houston, Texas 77004 D. Van Der Helm, Department of Chemistry, University of Oklahoma, Norman, Oklahoma 73019 |
| Abstract: | The synthesis of 2-azaphenoxathiin 2-oxide ( 4 ) and the total assignment of the 13C-nmr spectrum is described. Facile assignment was obtained from the assigned spectrum of 2-azaphenoxathiin with additivities obtained from a comparison of 1-azaphenoxathiin and its N-oxide. The crystal structure has also been determined from three dimensional X-ray diffraction data. The compound crystallizes in the monoclinic space group P21/n with a = 17.50(2)Å, b = 7.147(3)Å, c = 16.044(7)Å, β = 110.60(5) and Z = 8. Intensity data were collected at - 135 ± 2°C on an automatic diffractometer using nickel-filtered CuKα radiation. The structure was solved by direct methods and was refined by least-squares techniques to give a final R-value of 0.045 for all 3831 independent reflections. |
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