- Approach to 5-substituted 6,7,8,9-tetrahydro-5H-pyrido[3,2-c]azepines
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An approach to 5-substituted 6,7,8,9-tetrahydro-5H-pyrido[3,2-c]azepines via the cyclization of 1-(2-(3-azidopropyl)pyridin-3-yl)alkanones under Staudinger–aza-Wittig reaction conditions is described. The overall reaction sequence includes eight steps and allows for the preparation of gram quantities of the title products. In some cases, the formation of 5,7,8,9-tetrahydrooxepino[4,3-b]pyridine derivatives was observed.
- Subota, Andrii I.,Artamonov, Oleksiy S.,Gorlova, Alina,Volochnyuk, Dmitriy M.,Grygorenko, Oleksandr O.
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p. 1989 - 1991
(2017/04/27)
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- Approach to 3-(Cyclo)alkylpiperidines through 'sp3-sp3 via sp2-sp3' Coupling
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The idea of introducing (cyclo)alkyl substituents at the C-3 atom of the piperidine ring, that is, formal sp3-sp3 retrosynthetic disconnection, is implemented through a two-step reaction sequence including directed ortho metalation of a pyridine derivative and the subsequent quenching with a carbonyl compound, followed by catalytic hydrogenation. This robust but very efficient method allows for multigram preparation of sp3-rich 3-(cyclo)alkylpiperidines, which are valuable building blocks for medicinal chemistry and other areas.
- Subota, Andrii I.,Grygorenko, Oleksandr O.,Valter, Yevheniia B.,Tairov, Maxim A.,Artamonov, Oleksiy S.,Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.
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supporting information
p. 408 - 411
(2015/02/19)
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- Generation and reactions of pyridyllithiums via Br/li exchange reactions using continuous flow microreactor systems
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A continuous flow microreactor method for generating and carrying out reactions on pyridyllithiums has been developed based on Br/Li exchange reactions of bromopyridines and dibromopyridines. The reactions can be carried out without using cryogenic conditions by virtue of short residence times and efficient heat transfer, while very low temperatures such as-78 or-110°C are required for conventional batch macro methods. Moreover, sequential introduction of two different electrophiles has been successfully achieved using dibromopyridines in an integrated flow microreactor system composed of four micromixers and four microtube reactors.
- Nagaki, Aiichiro,Yamada, Daisuke,Yamada, Shigeyuki,Doi, Masatomo,Ichinari, Daisuke,Tomida, Yutaka,Takabayashi, Naofumi,Yoshida, Jun-Ichi
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p. 199 - 207
(2013/03/28)
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- Flow microreactor synthesis of disubstituted pyridines from dibromopyridines via Br/Li exchange without using cryogenic conditions
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A flow microreactor method for the synthesis of disubstituted pyridines by generation of pyridyllithiums followed by reactions with electrophiles has been developed. By using a short residence time and efficient temperature control, the cryogenic conditions required for conventional batch macro processes can be avoided. Sequential introduction of two different electrophiles into dibromopyridines has been achieved using an integrated flow microreactor system composed of four micromixers and four microtube reactors, to obtain disubstituted pyridine compounds.
- Nagaki, Aiichiro,Yamada, Shigeyuki,Doi, Masatomo,Tomida, Yutaka,Takabayashi, Naofumi,Yoshida, Jun-Ichi
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supporting information; experimental part
p. 1110 - 1113
(2011/06/26)
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- Synthesis of 3-substituted indazoles and benzoisoxazoles via Pd-catalyzed cyclization reactions: application to the synthesis of nigellicine
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Syntheses of 3-substituted indazoles and benzoisoxazoles were efficiently accomplished with the aid of Pd-catalyzed intramolecular carbon-nitrogen and carbon-oxygen bond formations. The catalyst system described herein allows the cyclization to proceed under very mild conditions and thus could be applied to a wide range of substrates with acid- or base-sensitive functional groups. A total synthesis for the indazole ring-containing natural product nigellicine is also described.
- Inamoto, Kiyofumi,Katsuno, Mika,Yoshino, Takashi,Arai, Yukari,Hiroya, Kou,Sakamoto, Takao
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p. 2695 - 2711
(2007/10/03)
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- TRIAZOLE DERIVATIVES AS TACHYKININ RECEPTOR ANTAGONISTS
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This application relates to a compound of Formula (I) or a pharmaceutically acceptable salt thereof, pharmaceutical compositions thereof, and its use as an inhibitor of the NK-1 subtype of tachykinin receptors, as well as a process for its preparation and intermediates therefor. (I) wherein: D is a C1-C3 alkane-diyl; R1 is phenyl, which is optionally substituted with one to three substitutents indpendently selected from the group consisting of halo, C1-C4 alkyl, C1-C4 alkoxy, cyano, difluoromethyl, trifluoromethyl, and trifluoromethoxy; R4 is a radical selected from the group consisting of: (IA), (IB), (IC), (ID), (IE), (IF), (IG), (IH)
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Page/Page column 41
(2010/02/07)
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- New syntheses of substituted pyridines via bromine-magnesium exchange
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Bromine-magnesium exchange using iPrMgCl in THF at room temperature on 2-, 3- and 4-bromopyridines allowed the synthesis of various functionalized pyridines. The methodology was successfully used for the synthesis of 4- azaxanthone. Moreover, single exchange reactions observed on 2,6-, 3,5-, 2,3- and 2,5-dibromopyridines, with complete regioselectivity in the case of 2,3- and 2,5-dibromopyridines, afforded substituted bromopyridines, which were then involved in a second exchange step to provide difunctionalized pyridines. (C) 2000 Elsevier Science Ltd.
- Trécourt, Fran?ois,Breton, Gilles,Bonnet, Véronique,Mongin, Florence,Marsais, Francis,Quéguiner, Guy
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p. 1349 - 1360
(2007/10/03)
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- Pyridylmagnesium chlorides from bromo and dibromopyridines by bromine- magnesium exchange: A convenient access to functionalized pyridines
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Various bromopyridines were converted to the corresponding pyridylmagnesium chlorides at room temperature by treatment with iPrMgCl. The resulting Grignard reagents were quenched by various electrophiles to afford functionalized pyridines. The bromine-magnesium exchange of some dibromopyridines was also studied.
- Trecourt, Francois,Breton, Gilles,Bonnet, Veronique,Mongin, Florence,Marsais, Francis,Queguiner, Guy
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p. 4339 - 4342
(2007/10/03)
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- Preparation of Didehydropyridines from (Trimethylsilyl)pyridines
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Halogen-substituted (trimethylsilyl)pyridines 2, 3, 5-7 and trifluoromethylsulfonyloxy-substituted (trimethylsilyl)pyridines 9b, 11b are obtained from 2- and 3-halopyridines 1, 4 or hydroxypyridines 8, 10, and 12.Reactions of the 3- and 2-(trimethylsilyl)pyridines 2, 9b and 11b with bases in the presence of furans 15 give only protodesilylation or hydrolysis products but no indication is found for the formation of a 2,3-didehydropyridine. 3-Bromo-4-(trimethylsilyl)pyridine (5a) reacts with KOCMe3 in the presence of furan (15a) to give a mixture of products from which the isoquinoline derivative 20 and the tert-butoxypyridines 23, 24 are formed by addition to 3,4-didehydropyridine.Under comparable conditions far higher yields of 3,4-didehydropyridines are obtained by treatment of the 3-halo-2,4-bis(trimethylsilyl)pyridines 7 with strong bases. Key Words: Didehydropyridines, synthesis of
- Effenberger, Franz,Daub, Wolfgang
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p. 2119 - 2125
(2007/10/02)
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