Date of Award
Dapsone is a drug which has recently been discovered as a potential treatment for the disease of leprosy. Many of the derivatives of dapsone have been sent to the United States by Dr. M. Muhundam and Professor M.S.R. Naidu of the Department of Chemistry, S.V. University, Tirupati, India, for structure analysis. One such derivative is (E)-3-[2-[(4-Chlorophenyl) sulphonyl] ethenyl]-4H-l-benzopyran-4-one, which will hereafter be referred to as MM3. MM3 was synthesized and the initial data for the structural analysis taken in the departments of Physics and Chemistry at S.V. University, Tirupati, India. The drug has been found to have a high antibacterial activity and hence may become a treatment for the cure of leprosy. However, to understand the full potential of the drug, the structural and conformational study needs to be performed. The "structural formula and geometric details ... [are] of primarv interest, to the chemist and biochemist who are concerned with the relation of the structural features to chemical properties" (Glusker and Trueblood 5). These chemical properties may help the chemist and biochemist to determine what functional groups need to be added to the drug to make it more effective by increasing the activity of the drug.
The author of this work has determined the crystal structure of MM3 by X-ray diffraction analysis. X-ray crystallography has become standard in structure determination since 1913 when W.L. 1 2 Bragg first used X-ray diffraction to determine the crystalline structure of sodium chloride, ordinary table salt. The X-ray diffraction technique had been first discovered just a year before by Max von Laue, a physicist interested in X-rays. Von Laue suggested that "Friedrich and Knipping try diffracting X rays by crystals in order to test the hypothesis that X rays are wavelike with wavelengths of the order of 1 ..." angstrom (10**-10 m) (Glusker and Trueblood 9). X-rays are used for structural study since the wavelength is comparable to the interatomic dimensions. He used surmises of Kepler (1611) and Hooke (1665) and logical conclusions by Bergman (1773) and Hauy (1782) "that crystals have an internal structure that is periodic (regularly repeating) in three dimensions ..." (Glusker and Trueblood 8). The experiment was surprisingly successful and led to the technique for determining crystal structure employed by Bragg. Von Laue guessed that X-rays have wavelengths near the dimensions of atomic bonds and nuclei in a crystal. The determination of the structure of crystals has become increasingly popular to chemists and physicists because of the relationship between structure and activity of all kinds of crystallized materials. From simple sodium chloride to complex proteins and viruses, the crystal structure has greatly contributed in an essential way to the understanding of biochemistry and molecular biology (Glusker and Trueblood 9).
This study finds the exact bond angles and lengths between atoms in the molecule, the unit cell (basic regular repeating 3 block) in a crystal of MM3, and the symmetrical way in which the molecules are packed together in this cell.
Heltcel, Tommie L., "The Crystalline Structure of MM3, A Derivative of Dapsone" (1994). McCabe Thesis Collection. 9.