618-40-6Relevant academic research and scientific papers
Cobalt-Catalyzed, Directed Intermolecular C-H Bond Functionalization for Multiheteroatom Heterocycle Synthesis: The Case of Benzotriazine
Wu, Weiping,Fan, Shuaixin,Li, Tielei,Fang, Lili,Chu, Benfa,Zhu, Jin
supporting information, p. 5652 - 5657 (2021/08/01)
Transition-metal-catalyzed, directed intermolecular C-H bond functionalization is synthetically useful but heavily underexplored in multiheteroatom heterocycle synthesis. Herein we report a cobalt catalytic method for the formation of a three-nitrogen-bearing benzotriazine scaffold via the coupling of arylhydrazine and oxadiazolone. This synthetic protocol features a low-cost base metal catalyst, a maximum number of heteroatoms built into a heterocycle, a distinct synthetic logic for benzotriazines, a superior step economy, and a broad substrate scope.
Rh(iii)-catalyzed, hydrazine-directed C-H functionalization with 1-alkynylcyclobutanols: A new strategy for 1: H -indazoles
Zhang, Lei,Chen, Junyu,Chen, Xiahe,Zheng, Xiangyun,Zhou, Jian,Zhong, Tianshuo,Chen, Zhiwei,Yang, Yun-Fang,Jiang, Xinpeng,She, Yuan-Bin,Yu, Chuanming
supporting information, p. 7415 - 7418 (2020/07/15)
Rh(iii)-catalyzed coupling of phenylhydrazines with 1-alkynylcyclobutanols was realized through a hydrazine-directed C-H functionalization pathway. This [4+1] annulation, based on the cleavage of a Csp-Csp triple bond in alkynylcyclobutanol, provides a new pathway to prepare diverse 1H-indazoles under mild reaction conditions. This journal is
N-Isocyanodialkylamines generated in situ for the Joullié–Ugi reaction with indolenines
Golubev, Pavel,Krasavin, Mikhail
supporting information, p. 3532 - 3536 (2018/08/29)
N-Isocyanodialkylamines are rare isocyanide surrogates for the Ugi-type reactions. To avoid problems with instability and the obnoxious smell of these reagents, we optimized and employed a convenient protocol for in situ dehydration of N,N-dialkyl-N′-formyl hydrazines to give the respective N-isocyanodialkylamines which were utilized in the reaction with indolenines and acetic acid. The reaction was demonstrated to give modest to excellent yields of products incorporating the N-isocyanodialkylamine but not the carboxylic acid component.
A Versatile, Traceless C-H Activation-Based Approach for the Synthesis of Heterocycles
Zhou, Shuguang,Wang, Jinhu,Zhang, Feifei,Song, Chao,Zhu, Jin
supporting information, p. 2427 - 2430 (2016/06/09)
A versatile, traceless C-H activation-based approach for the synthesis of diversified heterocycles is reported. Rh(III)-catalyzed, N-amino-directed C-H alkenylation generates either olefination products or indoles (in situ annulation) in an atom- and step-economic manner at room temperature. The remarkable reactivity endowed by this directing group enables scale-up of the reaction to a 10 g scale at a very low catalyst loading (0.01 mol %/0.1 mol %). Ex situ annulation of olefination product provides entry into an array of heterocycles.
An efficient synthesis of: N -nitrosamines under solvent, metal and acid free conditions using tert -butyl nitrite
Chaudhary, Priyanka,Gupta, Surabhi,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
supporting information, p. 2323 - 2330 (2016/05/19)
Synthesis of various N-nitroso compounds from secondary amines is reported using tert-butyl nitrite (TBN) under solvent free conditions. Broad substrate scope, metal and acid free conditions, easy isolation procedure and excellent yields are few important features of this methodology. The acid labile protecting groups such as tert-butyldimethylsilyl (TBDMS) and tert-butyloxycarbonyl (Boc) as well as sensitive functional groups such as phenols, olefins and alkynes are found to be stable under the standard reaction conditions. Besides N-nitrosation, TBN is also found to be an efficient reagent in few other transformations including aryl hydrazines to aryl azides and primary amides to carboxylic acids under mild conditions.
Ruthenium(II)-Catalyzed Traceless C?H Functionalization Using an N?N Bond as an Internal Oxidant
Zhou, Shuguang,Wang, Jinhu,Chen, Pei,Chen, Kehao,Zhu, Jin
supporting information, p. 14508 - 14512 (2016/10/03)
A previously elusive RuII-catalyzed N?N bond-based traceless C?H functionalization strategy is reported. An N-amino (i.e., hydrazine) group is used for the directed C?H functionalization with either an alkyne or an alkene, affording an indole derivative or olefination product. The synthesis features a broad substrate scope, superior atom and step economy, as well as mild reaction conditions.
Scandium(III) catalysis of transimination reactions. Independent and constitutionally coupled reversible processes
Giuseppone, Nicolas,Schmitt, Jean-Louis,Schwartz, Evan,Lehn, Jean-Marie
, p. 5528 - 5539 (2007/10/03)
Sc(OTf)3 efficiently catalyzes the self-sufficient transimination reaction between various types of C=N bonds in organic solvents, with turnover frequencies up to 3600 h-1 and rate accelerations up to 6 × 105. The mechanism of the crossover reaction in mixtures of amines and imines is studied, comparing parallel individual reactions with coupled equilibria. The intrinsic kinetic parameters for isolated reactions cannot simply be added up when several components are mixed, and the behavior of the system agrees with the presence of a unique mediator that constitutes the core of a network of competing reactions. In mixed systems, every single amine or imine competes for the same central hub, in accordance with their binding affinity for the catalyst metal ion center. More generally, the study extends the basic principles of constitutional dynamic chemistry to interconnected chemical transformations and provides a step toward dynamic systems of increasing complexity.
Synthesis and properties of amorphous hole transport materials of triphenylamine based trihydrazones
Jiang, Ke Jian,Sun, Ya Li,Shao, Ke Feng,Yang, Lian Ming
, p. 50 - 51 (2007/10/03)
A novel class of amorphous state triphenylamine-based trihydrazones were synthesized by condensation reaction of tris(p-formylphenyl)amine with N-methyl-N-phenyl hydrazine, N,N-diphenylhydrazine, N-1-naphthyl-N-phenyl- hydrazine, and N-2-naphthyl-N-phenyl-hydrazine, respectively, and characterized using different scanning calorimetry (DSC) and cyclic voltammetry (CV).
Amidrazones. 14. The Formation of 1,1-Disubstituted Hydrazines from the Base-promoted Hydrolysis of 1,1-Disubstituted-3-amino-4,5-dihydro-1H-pyrazolium Halides: Mechanistic Considerations
Smith, Richard F.,Dennis, Lisa A.,Ryan, William J.,Rodriguez, George,Brophy, Keith A.
, p. 181 - 183 (2007/10/02)
Three mechanistic pathways are considered for the hydroxide-promoted conversion of 1,1-disubstituted-3-amino-4,5-dihydro-1H-pyrazolium halides 1 to 1,1-disubstituted hydrazines, ammonia and sodium 3-hydroxypropanoate.Evidence presented in this paper supports a hydrolysis mechanism c that is initiated by hydroxide ion addition to the 3-position of 1 to form a tetrahedral intermediate 7.
Method for preparing indole carboxylic acid derivatives
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, (2008/06/13)
A method of preparing indole carboxylic acid derivatives from aniline derivatives is described which can be carried out in a single reaction vessel without any isolation of intermediate products. The method involes reacting an aniline derivative with a soluble nitrite in an acid medium, reducing the resulting nitrosamine by treating the acidic nitrosamine containing reaction solution with zinc in the presence of sufficient acid, optionally with addition of additional acid and/or a solvent such as a lower alcohol, reacting the resulting hydrazine derivative containing solution with a lower alkyl ester of pyruvic acid to obtain a corresponding hydrazone which cyclizes to yield an indole carboxylic acid ester, and if desired, hydrolyzing the ester to obtain the corresponding carboxylic acid.
