- New singlet oxygen donors based on naphthalenes: Synthesis, physical chemical data, and improved stability
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Singlet oxygen donors are of current interest for medical applications, but suffer from a short half-life leading to low singlet oxygen yields and problems with storage. We have synthesized more than 25 new singlet oxygen donors based on differently substituted naphthalenes in only a few steps. The influence of functional groups on the reaction rate of the photooxygenations, thermolysis, half-life, and singlet oxygen yield has been thoroughly studied. We determined various thermodynamic data and compared them with density functional calculations. Interestingly, remarkable stabilities of functional groups during the photooxygenations and stabilizing effects for some endoperoxides during the thermolysis have been found. Furthermore, we give evidence for a partly concerted and partly stepwise thermolysis mechanism leading to singlet and triplet oxygen, respectively. Our results might be interesting for "dark oxygenations" and future applications in medicine.
- Klaper, Matthias,Linker, Torsten
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- Photooxidation of methylnaphthalenes
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(Chemical Equation Presented). Studies on the photooxidation of methyl-substituted aromatic hydrocarbons have revealed that whereas electron density is a determinant of endoperoxide formation, steric factors are most important in influencing the stability of the endoperoxide. Additional information on the energetics of the reactions and on the magnitude of the steric interactions was obtained using calculations at the B3LYP/6-311+G* level of theory.
- Wasserman, Harry H.,Wiberg, Kenneth B.,Larsen, David L.,Parr, Jonathan
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p. 105 - 109
(2007/10/03)
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- Naphthalenes via microwave irradiation induced rearrangement on montmorillonite K-10
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Irradiation of 4-aryl-4-alkylhex-5-en-2-ones (e.g. la) or 5-aryl-4-alkylhex-5-en-2-ones (e.g. 2a) adsorbed on montmorillonite K-10 in a commercial microwave oven furnishes the multialkylated naphthalenes (e.g. 3).
- Srikrishna,Praveen Kumar
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p. 6313 - 6316
(2007/10/02)
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- Acid induced rearrangement of α,γ-unsaturated ketones
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The molecular rearrangement of the ketones (1), (10) and (19) to phenanthrene derivative (3) and decalin derivative (11) and (12) is respectively described.
- Banerjee, Ajoy K.,Acevedo, Julio C.,Gonzalez, Rosana,Rojas, Anibal
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p. 2081 - 2086
(2007/10/02)
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- INTRODUCTION OF METHYL GROUPS INTO POLYCYCLIC COMPOUNDS THROUGH THE PHOSPHONIUM SALTS OF METHYLNAPHTHALENE AND 9-METHYLPHENANTHRENE
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Chloromethyl derivatives synthesized by the chloromethylation of naphthalene and methylnaphthalenes were converted into the corresponding triphenylphosphonium salts.Alkaline hydrolysis of the latter gave 1-methylnaphthalene and some di-, tri-, and tetramethylnaphthalenes. 9-Methylphenanthrene was obtained similarly from phenanthrene.The corresponding diarylethenes were synthesized from the phosphonium salts by the Wittig reaction.
- Listvan, V. N.,Stasyuk, A. P.
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p. 354 - 359
(2007/10/02)
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