179729-49-8Relevant academic research and scientific papers
Photoinduced DNA cleavage by atomic oxygen precursors in aqueous solutions
Korang, James,Emahi, Ismaila,Grither, Whitney R.,Baumann, Sara M.,Baum, Dana A.,McCulla, Ryan D.
, p. 12390 - 12397 (2013/09/02)
Reactive oxygen species are known to induce DNA strand cleavage and have been explored as treatments for cancer. The development of aqueous-soluble dibenzothiophene-S-oxide (DBTO) derivatives has made it possible to investigate the mechanism of DNA cleavage by these photoactivatable precursors of atomic oxygen. In addition to the release of atomic oxygen, DBTO can also undergo other processes such as α-cleavage. An objective of this work was to establish whether the extent of strand scission could be attributed to a direct reaction between atomic oxygen and DNA. To accomplish this aim, the extent of strand cleavage upon irradiation of three different DBTO derivatives was measured by the conversion of circular pUC19 plasmid (Form I) to nicked (Form II) as monitored by gel electrophoresis. The interaction of the sulfoxides with DNA was systematically studied by optical melt and fluorescence anisotropy experiments. Thiols are susceptible to rapid oxidation by atomic oxygen, and thus, glutathione was used as a ROS scavenger to determine if DNA cleavage was induced by the release of atomic oxygen. The results from these experiments indicated atomic oxygen was at least partially responsible for the observed strand scission. The Royal Society of Chemistry 2013.
Photodeoxygenation of dibenzothiophene S-oxide derivatives in aqueous media
Korang, James,Grither, Whitney R.,McCulla, Ryan D.
scheme or table, p. 4466 - 4476 (2010/06/13)
The use of atomic oxygen (O(3P)) as potent oxidant In water has suffered from the lack of a facile, efficient source. The photodeoxygenatlon of aromatic sulfoxides to the corresponding sulfides in organic solvents has been suggested to produce O(3P) in low quantum yields. The photolysis of 4,6-dihydroxymethyldibenzothiophene S-oxide and 2,8- dihydroxymethyldibenzothiophene S-oxide in water results in deoxygenation at significantly higher quantum yields than In organic solvents. Depending upon conditions, a variable amount of oxidation of the hydroxymethyl substituent into an aldehyde was observed to accompany deoxygenation. Analysis of the photoproducts Indicated the deoxygenation occurred by at least two different pH-sensitive mechanisms. Under basic conditions, photoinduced electron transfer yielding a hydroxysulfuranyl radical that decomposed by heterolytlc S-O cleavage was thermodynamically feasible. The thermodynamics of photoinduced electron transfer were expected to become increasingly unfavorable as the pH of the solution decreased. Thus, at neutral and acidic pH, an S-O bond scission mechanism was suspected. The observed increase In the photodeoxygenation quantum yields was consistent with charge separation accompanying S-O bond scission. Oxidative cleavage of alkenes In aerobic conditions suggested O(3P) was produced during photolysis In these conditions; however, the formation of discrete O-/HO may occur, particularly at low pH.
Conformationally restricted diamines as spacers for parallel β-sheet formation
Skar, Merete L.,Svendsen, John S.
, p. 17425 - 17440 (2007/10/03)
The dibenzofuran-based diamide 4,6-bis(N-acyl-aminomethyl)dibenzofuran is shown by 1H NMR and IR to have favourable geometry for intramolecular hydrogen bonding. The corresponding dibenzothiophene-based diamide 4,6-bis(N-acyl-aminomethyl)dibenzothiophene does not fulfill the geometric requirements for intramolecular hydrogen bonding. The intramolecularly hydrogen bonded state of the dibenzofuran-based diamide la is found to be 1 ± 0.5 kcal/mol more favoured enthalpically and 4 ± 2 cal/(K·mol) disfavoured entropically than the non-hydrogen bonded state.
