- Transition-Metal-Free Synthesis of Pyridine Derivatives by Thermal Cyclization of N -Propargyl Enamines
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A transition-metal-free synthesis of pyridine derivatives by 6- endo - dig cyclization of N -propargyl enamines was developed. This method is environmentally friendly and is a high atom economy reaction that is easily accessed to provide pyridine derivatives in moderate to good yield by heating N -propargyl enamines in solvent without additives. The total synthesis of onychine was achieved in 51% yield in only two steps by using this method.
- Chikayuki, Yuya,Higashiyama, Kimio,Kirita, Akiko,Matsuo, Natsuko,Miyashige, Takakane,Sasaki, Shigeru,Teramoto, Hiroyoshi,Yamauchi, Takayasu,Yonekawa, Shiori
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p. 1113 - 1121
(2020/04/01)
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- Synthesis of 3-Keto Pyridines from the Conjugated Allenone – Alkynylamine Oxidative Cyclization Catalyzed by Supported Au Nanoparticles
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Recyclable supported Au nanoparticles on TiO2 catalyze the cyclization of N-propargyl or N-homopropargyl β-enaminones followed by dehydrogenation (aromatization) leading to substituted 3-keto pyridines or 4-picolines in very good yields. This pathway is in contrast to their known cyclization in the presence of Au(I) or Au(III) catalysts which provides 1,4-oxazepines, instead. The enaminones are formed in situ upon mixing a conjugated allenone or allenyl ester with the alkynylamine, thus the pyridine-forming transformation is typically a one pot process. (Figure presented.).
- Fragkiadakis, Michael,Kidonakis, Marios,Stratakis, Manolis,Zorba, Leandros
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supporting information
p. 964 - 968
(2020/01/28)
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- Synthesis of 3-Acylpyrroles, 3-(Alkoxycarbonyl)pyrroles, 1,5,6,7-Tetrahydro-4H-indol-4-ones and 3-Benzoylpyridines Based on Staudinger-Aza-Wittig Reactions of 1,3-Dicarbonyl Compounds with 2- and 3-Azido-1,1-dialkoxy- alkanes
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The Staudinger-aza-Wittig reaction of 1,3-dicarbonyl compounds with 2-azido-1,1-diethoxyethane and subsequent cy- clization allowed an efficient synthesis of a variety of pyrroles, 1,5,6,7-tetrahydro-4H-indol-4-ones, and of a pyridine. Georg Thieme Verlag
- Bellur, Esen,Yawer, Mirza A.,Hussain, Ibrar,Riahi, Abdolmajid,Fatunsin, Olumide,Fischer, Christine,Langer, Peter
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experimental part
p. 227 - 242
(2009/06/24)
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