- Synthesis of diverse 2,3-dihydroindoles, 1,2,3,4-tetrahydroquinolines, and benzo-fused azepines by formal radical cyclization onto aromatic rings
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(Chemical Equation Presented) 2,3-Dihydroindoles, 1,2,3,4- tetrahydroquinolines, and 2,3,4,5-tetrahydrobenzo[b]azepines are available by a process that represents formal radical cyclization onto aromatic rings. Optically pure benzo-fused heterocycles are also accessible by this method. p-Iodophenols, especially those with the phenolic oxygen protected as a MOM-ether, can be coupled with amino alcohols to produce N-aryl amino alcohols, which can be converted into the corresponding alkyl iodides in which the nitrogen is protected as a carbamate. These compounds give cross-conjugated ketones after removal of the phenolic protecting group and oxidation with PhI(OAc)2 in the presence of MeOH. The ketones undergo 5-, 6- or 7-exo-trigonal radical cyclization, and then exposure to acid, or sequential treatment with a Grignard reagent and then acid, effects rearomatization to produce the benzo-fused nitrogen heterocycles.
- Clive, Derrick L. J.,Peng, Jianbiao,Fletcher, Stephen P.,Ziffle, Vincent E.,Wingert, David
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p. 2330 - 2344
(2008/09/19)
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- Oxidation of p-aminophenols and formal radical cyclization onto benzene rings: Formation of benzo-fused nitrogen heterocycles
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(Chemical Equation Presented) p-Iodophenol and its O-MOM-protected ether can be converted into iodoamines 2. These give cross-conjugated ketones 3 on oxidation with hypervalent iodides in the presence of methanol, and the ketones undergo radical cyclization. Exposure of the products to acid or sequential treatment with a Grignard reagent and acid effects rearomatization to produce benzo-fused nitrogen heterocycles 4.
- Fletcher, Stephen P.,Clive, Derrick L. J.,Peng, Jianbiao,Wingert, David A.
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- Studies on Cytotoxicity Associated with Melanin Pigmentation: Attempted Synthesis of N-4-Hydroxyphenylaziridine
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In an attempt to synthesise N-4-hydroxyphenylaziridine (II), a derivative of II in which the hydroxyl group is protected has been prepared.However, removal of protective group without concomitant opening of the aziridine ring has not been successful.
- Fayadh, J. M.,Swan, G. A.
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p. 222 - 224
(2007/10/02)
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