- Palladium-catalyzed domino double n-arylations (inter- and intramolecular) of 1,2-diamino(hetero)arenes with o,o-dihalo(hetero)arenes for the synthesis of phenazines and pyridoquinoxalines
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Domino reactions for the synthesis of phenazines have been developed that start from 1,2-diaminoarenes and 1,2-dihaloarenes and proceed through palladium-catalyzed double N-arylations (inter- and intramolecular) followed by an in situ oxidation. A variety of functional groups, which include base-sensitive groups, were well tolerated under the optimized reaction conditions to afford phenazines in good to excellent yields. The protocol was extended to the synthesis of pyridoquinoxalines by employing either o-phenylenediamines and 2,3-dihalopyridines or 1,2-diaminopyridines and 1,2-dihaloarenes. Domino reactions for the synthesis of phenazines have been developed that start from 1,2-diaminoarenes and 1,2-dihaloarenes and proceed through palladium-catalyzed double N-arylations (inter- and intramolecular) followed by an in situ oxidation. The protocol was extended to the synthesis of pyridoquinoxalines. Copyright
- Laha, Joydev K.,Tummalapalli, K.S. Satyanarayana,Gupta, Ankur
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p. 8330 - 8335
(2014/01/06)
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- Efficient methods for the synthesis of 2-hydroxyphenazine based on the Pd-catalyzed N-arylation of aryl bromides
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(Chemical Equation Presented) Substituted diphenylamines can be synthesized by Pd(0)-catalyzed N-arylation using o-nitroanilines and nitro-substituted aryl bromides for a substrate. Cyclization of the diphenylamines by various methods, including the intramolecular Pd(0)-catalyzed N-arylation, produces 2-methoxyphenazine which can easily be deprotected to give 2-hydroxyphenazine. This phenazine is required to synthesize methanophenazine, a novel redoxactive cofactor isolated from methanogenic archaea.
- Tietze, Mario,Iglesias, Alberto,Merisor, Elena,Conrad, Juergen,Klaiber, Iris,Beifuss, Uwe
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p. 1549 - 1552
(2007/10/03)
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