- Cobalt-Catalyzed, Directed Intermolecular C-H Bond Functionalization for Multiheteroatom Heterocycle Synthesis: The Case of Benzotriazine
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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.
- Wu, Weiping,Fan, Shuaixin,Li, Tielei,Fang, Lili,Chu, Benfa,Zhu, Jin
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supporting information
p. 5652 - 5657
(2021/08/01)
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- Rh(iii)-catalyzed, hydrazine-directed C-H functionalization with 1-alkynylcyclobutanols: A new strategy for 1: H -indazoles
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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
- Zhang, Lei,Chen, Junyu,Chen, Xiahe,Zheng, Xiangyun,Zhou, Jian,Zhong, Tianshuo,Chen, Zhiwei,Yang, Yun-Fang,Jiang, Xinpeng,She, Yuan-Bin,Yu, Chuanming
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p. 7415 - 7418
(2020/07/15)
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- N-Isocyanodialkylamines generated in situ for the Joullié–Ugi reaction with indolenines
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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.
- Golubev, Pavel,Krasavin, Mikhail
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p. 3532 - 3536
(2018/08/29)
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- An efficient synthesis of: N -nitrosamines under solvent, metal and acid free conditions using tert -butyl nitrite
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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.
- Chaudhary, Priyanka,Gupta, Surabhi,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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p. 2323 - 2330
(2016/05/19)
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- A Versatile, Traceless C-H Activation-Based Approach for the Synthesis of Heterocycles
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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.
- Zhou, Shuguang,Wang, Jinhu,Zhang, Feifei,Song, Chao,Zhu, Jin
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supporting information
p. 2427 - 2430
(2016/06/09)
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- Ruthenium(II)-Catalyzed Traceless C?H Functionalization Using an N?N Bond as an Internal Oxidant
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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.
- Zhou, Shuguang,Wang, Jinhu,Chen, Pei,Chen, Kehao,Zhu, Jin
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supporting information
p. 14508 - 14512
(2016/10/03)
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- Scandium(III) catalysis of transimination reactions. Independent and constitutionally coupled reversible processes
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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.
- Giuseppone, Nicolas,Schmitt, Jean-Louis,Schwartz, Evan,Lehn, Jean-Marie
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p. 5528 - 5539
(2007/10/03)
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- Synthesis and properties of amorphous hole transport materials of triphenylamine based trihydrazones
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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).
- Jiang, Ke Jian,Sun, Ya Li,Shao, Ke Feng,Yang, Lian Ming
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- 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
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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.
- Smith, Richard F.,Dennis, Lisa A.,Ryan, William J.,Rodriguez, George,Brophy, Keith A.
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p. 181 - 183
(2007/10/02)
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- Method for preparing indole carboxylic acid derivatives
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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.
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- Regioselective Synthesis of 1-Alkyl-1-phenylhydrazines, 2-Alkyl-1-phenylhydrazines, and 1,2-Dialkyl-1-phenylhydrazines
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1,2- and 1,1-disubstituted and 1,1,2-trisubstituted hydrazines are obtained by reaction of (2-phenylhydrazino)triphenylphosphonium bromide with butyllithium, followed by addition of alkyl halides and alkaline hydrolysis.
- Barluenga, Jose,Merino, Isabel,Vina, Sara,Palacios, Francisco
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p. 398 - 400
(2007/10/02)
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- SIMPLE PREPARATION OF N-ALKYL-N-ARYLHYDRAZINES FROM DIAZOTABLE N-ARYLAMINES
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Phase-Transfer-catalyzed N-alkylation of arylhydrazones 2, followed by hydrazinolysis with hydrazine hydrate in the presence of concentrated hydrochloric acid, provides a new access to N-alkyl-N-arylhydrazines 3.
- Gonzalez, Asensio
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p. 1225 - 1230
(2007/10/02)
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- AMIDRAZONES 9. CONVENIENT SYNTHESIS OF 1-ALKYL-1-PHENYLHYDRAZINES AND α,β-UNSATURATED AMIDRAZONES VIA BASE-PROMOTED REACTIONS OF 1,1-DISUBSTITUTED-3-AMNIO-4,5-DIHYDRO-1H-PYRAZOLIUM SALTS.
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A simple, efficient procedure for the conversion of phenylhydrazine to 1-alkyl-1-phenylhydrazines via base-promoted hydrolysis of 1-alkyl-3-amino-4,5-dihydro-1-phenyl-1H-pyrazolium iodides (2) is described.N',N'-disubstituted hydrazones of trans-cinnamamide and acrylamide are obtained by Hofmann-type ring openings of 1,1-disubstituted-3-amino-4,5-dihydro-5-phenyl (or 5-unsubstituted) -1H-pyrazolium halides (5,7).
- Smith, Richard F.,Olson, Laurie A.,Ryan, William J.,Coffman, Karen J.,Galante, Julienne M.,et al.
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p. 585 - 596
(2007/10/02)
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- METHYLATION OF N-PHENYL-N'-ACETYLHYDRAZINE WITH DIMETHYL SULFATE
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The reaction of N-phenyl-N'-acetylhydrazine with dimethyl sulfate in benzene in the presence of a 40percent solution of sodium hydroxide leads to a mixture of N-methyl-N-phenyl-N'-acetylhydrazine (45percent), N,N'-dimethyl-N-phenyl-N'-acetylhydrazine (31percent), and N'-methyl-N-phenyl-N'acetylhydrazine (24percent).The dimethyl derivative is formed through the methylation of N-methyl-N-phenyl-N'-acetylhydrazine by dimethyl sulfate, whereas the other isomer does not react under these conditions.
- Barinova, V. N.,Voronin, V. G.,Zhestkov, V. P.,Portnov, Yu. N.
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p. 1609 - 1611
(2007/10/02)
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- Reduction of Nitrosamines with Aqueous Titanium Trichloride: Convenient Preparation of Aliphatic Hydrazines
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The reduction of selected nitrosamines by aqueous TiCl3 has been investigated.In general, aliphatic nitrosamines were converted in good yield to the corresponding hydrazines, with little overreduction to the amines.Reaction proceeded rapidly at room temperature in both alkaline and acidic media.A variety of N,N-dialkylhydrazines have been isolated by using the TiCl3 method, which compares favorably with previously reported procedures for preparatively converting nitrosamines to hydrazines.In the reduction of N-nitroso-N-methylaniline, the proportion of amine in the product increased significantly as the pH of the reaction mixture was lowered, presumably reflecting the known instability of arylalkylnitrosamines in strong acid, coupled with a ready reducibility of the corresponding Fischer-Hepp intermediates; some tendency toward reductive cleavage of the N-aryl-N-alkylhydrazine's N-N-bond was also noted.Reduction of an α-nitrosamino ether gave the monoalkylhydrazine as the major product, while all other reducing agents studied converted this starting material chiefly to a mixture of primary and secondary amines.
- Lunn, George,Sansone, Eric B.,Keefer, Larry K.
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p. 3470 - 3473
(2007/10/02)
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- STEREOSPECIFIC SYNTHESIS OF (E)- OR (Z)-α-STYLBAZOLE FROM 2-(TRIMETHYLSILYLMETHYL)PYRIDINE AND BENZALDEHYDE PHENYLHYDRAZONES
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In the presence of crown ethers, -cryptand, di-, tri-, or tetraglyme, lithiated 2-(trimethylsilylmethyl)pyridine reacts with benzaldehyde methylphenylhydrazone to give stereospecifically (E)- or (Z)-α-stylbazole in good yield.
- Konakahara, Takeo,Nishigaki, Hiromi,Watanabe, Atsuo,Sato, Kenji
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p. 2765 - 2768
(2007/10/02)
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- An efficient synthesis of 1,1-disubstituted hydrazines
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1,1-disubstituted hydrazines were prepared from the corresponding 1,1-disubstituted ureas by means of the Hofmann rearrangement reaction. The yields were fairly good, except from the ureas susceptible to oxidation, and thus the present method represents an additional and efficient procedure for the synthesis of 1,1-disubstituted hydrazines.
- Murakami,Yokoyama,Sasakura,Tamagawa
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p. 423 - 428
(2007/10/02)
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- METAL-ASSISTED REACTIONS-PART 11 RAPID REDUCTION OF N-NITROSOAMINES TO N,N-DISUBSTITUTED HYDRAZINES; THE UTILITY OF SOME LOW-VALENT TITANIUM REAGENTS
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The rapid reduction of N-nitrosoamines to N,N-disubstituted hydrazines by a low-valent titanium reagent is described.The reagent is selective in that many other functional groups are unaffected by it.The nature of the low-valent titanium reagent is discussed in terms of experimental results of comparisons of its reactivity and that of other low-valent titanium reducing agents.
- Entwistle, Ian D.,Johnstone, A. W.,Wilby, Anna H.
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p. 419 - 423
(2007/10/02)
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- Reactions of 4,5-Dihydro-5-methylpyranoindole-1,3-dione; a Synthesis of N-Methylisotryptophol
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Boiling 4,5-dihydro-5-methylpyranoindole-1,3-dione (7) with alcohols followed by decarboxylation of the half-esters so formed leads to esters of 1-methylindol-2-ylacetic acid; reduction of these esters then affords N-methylisotryptophol (10).Reaction of 3-carboxy-1-methylindol-2-ylacetic acid (6; R=H) with acetic acid-sodium acetate gives 3,5-dimethylpyranoindol-1(5H)-one (17); with dimethylformamide-phosphorus oxychloride, 4-(NN-dimethylaminomethylene)-4,5-dihydro-5-methylpyranoindole-1,3-dione (22) was obtained.
- Bahadur, Gulam A.,Baylei, A. Sydney,Middleton, Nigel W.,Peach, Josephine M.
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p. 1688 - 1692
(2007/10/02)
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