Current Search: Anarchism. (x) » info:fedora/fau:smc (x) » Department of Chemistry and Biochemistry (x) » Parkanyi, Cyril (x)
View All Items
- Title
- Photodegradation of bromacil and terbacil by ultraviolet radiation.
- Creator
- Johnson, Hannah Kalyani, Florida Atlantic University, Parkanyi, Cyril, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
The photodegradation of bromacil (5-bromo-3-sec-butyl-6-methyluracil) and terbacil (5-chloro-3-tert-butyl-6-methyluracil) by ultraviolet radiation has been investigated. Irradiation of aerated aqueous solutions of the title compounds (25 ppm), led to fast degradation of both. The reactions were found to follow first order kinetics with rate constants 5.77x10^-1 hr^-1 in the case of bromacil and 8.45x10^-2 hr^-1 in the case of terbacil. Degradation in ethanol and cyclohexane was also studied,...
Show moreThe photodegradation of bromacil (5-bromo-3-sec-butyl-6-methyluracil) and terbacil (5-chloro-3-tert-butyl-6-methyluracil) by ultraviolet radiation has been investigated. Irradiation of aerated aqueous solutions of the title compounds (25 ppm), led to fast degradation of both. The reactions were found to follow first order kinetics with rate constants 5.77x10^-1 hr^-1 in the case of bromacil and 8.45x10^-2 hr^-1 in the case of terbacil. Degradation in ethanol and cyclohexane was also studied, but the solutions were not analyzed for photoproducts. The photoreaction mixture of both the herbicides in water showed four peaks on GC, indicating four photoproducts. Loss of halogens from the heterocyclic ring has been observed as shown by the presence of Br- in the case of bromacil and Cl- in the case of terbacil in the photoreaction solution. 6-Methyluracil which was isolated from the aqueous fraction of the photoreaction mixture was the common photoproduct from both bromacil and terbacil. From the organic fractions 3-sec-butyl-5-acetyl-5-hydroxyhydantoin was identified in the case of bromacil and 3-tert-butyl-5-acetyl-5-hydroxyhydantoin in the case of terbacil. The other two photoproducts were left unidentified.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14929
- Subject Headings
- Ultraviolet radiation, Photochemistry--Deterioration, Herbicides, Uracil
- Format
- Document (PDF)
- Title
- Synthesis and In Vitro Evaluation of Some Novel Nucleoside analogs and DNA lntercalators as Potential Anticancer or Antiviral Agents.
- Creator
- Zhao, Yuxiang, Florida Atlantic University, Parkanyi, Cyril, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Thiadiazoles can be considered as analogs of pyrimidines because of the well known analogy between a -CH=CH- group in benzenoid hydrocarbons and bivalent sulfur, -S-, in aromatic heterocycles. Therefore, 5-amino-2H-1 ,2,4-thiadiazole-3-one and 5-amino-3H-1 ,3,4-thiadiazole-2-one are the analogs of cytosine. In our first project, the preparation of six thiadiazole nucleoside analogs is reported: 5-diacetylamino-1 ,2,4- thiadiazol-3-one (1), 5-amino-2-(tetrahydrofuran-2-yl)-1 ,2,4-thiadiazol-3...
Show moreThiadiazoles can be considered as analogs of pyrimidines because of the well known analogy between a -CH=CH- group in benzenoid hydrocarbons and bivalent sulfur, -S-, in aromatic heterocycles. Therefore, 5-amino-2H-1 ,2,4-thiadiazole-3-one and 5-amino-3H-1 ,3,4-thiadiazole-2-one are the analogs of cytosine. In our first project, the preparation of six thiadiazole nucleoside analogs is reported: 5-diacetylamino-1 ,2,4- thiadiazol-3-one (1), 5-amino-2-(tetrahydrofuran-2-yl)-1 ,2,4-thiadiazol-3-one (2), 5- amino-3-((2' -hydroxyethoxy)methyl)-1 ,3,4-thiadiazol-2-one (3), 5-amino-3-( 4' -hydroxy- 2' -hydroxyrnethyl-butyl)-1 ,3,4-thiadiazole-2-thione ( 4), (R)-5-am ino-3-(2' ,3' - dihydroxypropyl)-1 ,3,4-thiadiazole-2-thione (5), and (S)-5-amino-3-(2' ,3 ' - dihydroxypropyl )-1 ,3,4-thiadiazole-2-thione (6). (R)-5-amino-3-(2' ,3' -dihydroxypropyl)-1,3,4-thiadiazole-2-thione (5) and (S)-5-amino-3-(2' ,3' -dihydroxypropyl)-1 ,3,4- thiadiazole-2-thione (6) are stereoisomers. Their racemic mixture 7 was also prepared and tested. The synthesis, characterization, and properties of these new synthesized thiadiazole derivatives are discussed. A dimerization of 5-amino-3H-1 ,3 ,4-thiadiazole-2- thione (18) to produce di-(5-amino-1 ,3,4-thiadiazol-2-yl) disulfide (23) by sodium nitrite with either acetic acid or stannic chloride is also reported. Preliminary results indicate that 3 and 23 possess antimicrobial activity. In the second project, the synthesis of three series of bis-aminochloropyrimidine derivatives with different types of linkers as potential DNA intercalators is described. The first series are aminochloropyrimidines bridged by polyrnethylene chain linkers with various lengths. The second series are bridged by polyether linkers to lower the lipophilicity. The third series are bridged by linkers containing benzene rings to limit the flexibility. The spectral data and other physical properties of the new compounds are discussed. The preliminary screening results indicate that many new synthesized bisintercalators are biologically active. The relationship between bioactivity and structure is discussed as well.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000886
- Subject Headings
- Biopharmaceutics, Antineoplastic agents--Pharmacodynamics, Nucleosides--Metabolism, Pharmaceutical chemistry, Antiviral agents--Synthesis
- Format
- Document (PDF)