- Preparation of Hexahydrocarbazole Derivatives by Reductive Indolization
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The reductive indolization is a two-step protocol performed in one flask: First, the acid-mediated Fischer indolization of a cyclic ketone with phenylhydrazine forms an iminium ion which is subsequently reduced by a hydrido borate reagent to the indoline as the final product. We utilized this new strategy for the preparation of hexahydrocarbazole derivatives with a side chain in the quaternary C4a-position. Starting materials were several N1- and aryl-substituted phenylhydrazines and a cyclic ketone with propanoic ester moiety, which is the product of the conjugated addition of cyclohexanone to ethyl acrylate. Furthermore, benzannulated congeners as well as a pyrido[4,3-b]indole derivative were accessed. The hexahydrocarbazole defines a molecular scaffold with two points of diversification. Therefore, several derivatives at N9 and at the C4a-side chain were prepared.
- Christoffers, Jens,Dierks, Anna,Fliegel, Lukas,Schmidtmann, Marc
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p. 7164 - 7175
(2020/11/30)
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- Domino reaction of a gold catalyzed 5-: Endo-dig cyclization and a [3,3]-sigmatropic rearrangement towards polysubstituted pyrazoles
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Pyrazoles are important heterocyclic compounds with a broad range of biological activities. A new procedure toward tri- or tetrasubstituted pyrazoles has been developed, via a one-pot gold catalyzed synthesis from hydrazines with alkynyl aldehydes or keto
- Verlee, Arno,Heugebaert, Thomas,Van Der Meer, Tom,Kerchev, Pavel,Van Breusegem, Frank,Stevens, Christian V.
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p. 9359 - 9363
(2019/01/03)
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- Formation of enehydrazine intermediates through coupling of phenylhydrazines with vinyl halides: Entry into the Fischer indole synthesis
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Cut to the chase: Direct formation of an enehydrazine, an intermediate in the classic Fischer indole synthesis, solves the regioselectivity problem associated with indolization. This approach not only achieves selective synthesis of indoles through proper selection of the vinyl halide, but also leads to quick construction of desoxyeseroline and esermethole, as well as the key structural motif in the Akuammiline alkaloid vincorine. Copyright
- Zhan, Fuxu,Liang, Guangxin
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supporting information
p. 1266 - 1269
(2013/03/13)
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- Discovery of ectoparasiticidal hydrazonotrifluoromethanesulfonanilides
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A series of hydrazonotrifluorosulfonanilide derivatives were synthesized and evaluated for in vitro activity against the ectoparasites Ctenocephalides felis and Rhipicephalus sanguineus. Some compounds with excellent activity against tick were identified.
- Ali, Abdelselam,Fisara, Petr,Freemont, Jamie A.,Kyi, Stella,Meyer, Adam G.,Riches, Andrew G.,Sargent, Roger M.,Sawutz, David G.,Turner, Kathleen A.,Winzenberg, Kevin N.,Yang, Qi
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scheme or table
p. 649 - 652
(2010/06/12)
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- Investigation of the Potential of Molybdenum(VI) Hydrazido(2-) Complexes as Sources of Nitrenium Ions: Cleavage of the N-N Bond and Incorporation of the β-Nitrogen Group into Solvent Molecules
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Photolyis or thermolysis of bis(N,N-dimethyldithiocarbamato)bismolybdenum(VI) complexes in 1,1,2,2-tetrachloroethane results predominantly in transfer of the hydrazido group to the solvent with formation of dichloroacetohydrazides.A small amount of the corresponding dichloroacetamides are produced by N-N cleavage and N(R)Ph transfer.In contrast, the latter process dominates the reaction of dichlorobis(N,N-dimethyldithiocarbamato)mono-molybdenum(VI) complexes with silver nitrate in alcohols occuring concomitantly with ring methoxylation and nitration and N-nitrosation.Neither transfer of N(R)Ph appears to involve free nitrenium ions.
- Baum, Marc M.,Smith, Edward H.
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p. 2513 - 2520
(2007/10/02)
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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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- MASS SPECTRA OF ORGANIC DERIVATIVES OF HYDRAZINE. IV. SKELETAL REARRANGEMENTS IN THE MOLECULAR IONS OF ALLYLHYDRAZONES
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The fragmentation of the molecular ions of allyl-, alkylallyl-, methylpropargyl-, and phenylallylhydrazones of aliphatic carbonyl compounds is accompanied by migration of the allyl group, similar to a thermal 3,3-sigmatropic process.Five previously unknow
- Zenkevich, I. G.,Isidorov, V. A.,Ioffe, B. V.
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p. 1613 - 1621
(2007/10/02)
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