- Secondary phosphine oxides assisted palladium complexes catalyzed catellani reaction for the formation of carbazole derivatives
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Several secondary phosphine oxides (SPOs, 2a-2d) as well as 2a-chelated palladium complex 2a_Pd were employed in Catellani type reaction for the synthesis of 1-methyl-9H-carbazole (4) from 2-iodotoluene and N-(2-bromophenyl)acetamide (3). The application
- Chen, Ya-Chan,Chou, Hsueh-Min,Kao, I-Hsiang,Chang, Yu-Chang,Hong, Fung-E.
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- Synthesis of Carbazoles from 2-Iodobiphenyls by Palladium-Catalyzed C?H Activation and Amination with Diaziridinone
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A facile and efficient approach has been developed for the synthesis of carbazoles from 2-iodobiphenyls and diaziridinone under palladium catalysis. A wide range of carbazoles were synthesized in good to excellent yields, and indole derivatives were obtained by using styrenes as the substrate. The palladacycles obtained from 2-iodobiphenyls acted as the key intermediate, and the reaction should proceed via a tandem Pd-catalyzed C?H activation/dual C?N bond formation sequence. (Figure presented.).
- Shao, Changdong,Zhou, Bo,Wu, Zhuo,Ji, Xiaoming,Zhang, Yanghui
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- A versatile carbazole donor design strategy for blue emission switching from normal fluorescence to thermally activated delayed fluorescence
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The weak electron donating ability of carbazole is most suitable for constructing the donor-acceptor type blue emitters, but its low spatial requirements caused by the five-membered ring bridged structure is not favorable for spatial separation of frontier molecular orbitals. So many carbazole based compounds do not exhibit thermally activated delayed fluorescence (TADF). Herein, a more sterically demanding group was introduced at the 1-site of carbazole to form 1-methylcarbazole (1-MeCz), in order to construct a versatile donor for blue TADF materials. 1-MeCz was used as donor in combination with triazine and pyrimidine as acceptors to design novel compounds 1-MeCz-TRZ and 1-MeCz-Pm. It was observed that the presence of the methyl group at the 1-site of carbazole enhanced the twisted angles and reduced frontier molecular orbital overlapping, successfully switching the blue emission from the normal fluorescence of the methyl-free reference compounds (Cz-TRZ and Cz-Pm) to TADF of 1-MeCz-TRZ and 1-MeCz-Pm. The organic light-emitting diodes of 1-MeCz-TRZ and 1-MeCz-Pm exhibited blue emission at 450 and 458 nm with Commission Internationale de L'Eclairage (CIE) coordinates of (0.15, 0.11) and (0.17, 0.18), and external quantum efficiencies of 13.07% and 7.53%. This study provides a versatile, simple and practical design strategy with 1-MeCz to construct pure blue TADF emitters in combination with various acceptors.
- Dong, Ruizhi,Li, Jiuyan,Liu, Di,Niu, Rui,Shi, Chunlong,Tian, Houru,Wei, Wenkui
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- Stereospecific access to bridged [n.2.1] skeletons through gold-catalyzed tandem reaction of indolyl homopropargyl amides
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An efficient gold-catalyzed anti-Markovnikov cycloisomerization-initiated tandem reaction of Boc-protected indole tethered homopropargyl amides has been achieved. This method delivers a wide range of valuable bridged aza-[n.2.1] skeletons (n = 3–7) at room temperature with high diastereoselectivity and enantioselectivity by a chirality-transfer strategy. Moreover, the gold-catalyzed tandem reaction of homopropargyl alcohol is also achieved to produce the bridged oxa-[3.2.1] skeleton.
- Tan, Tong-De,Zhu, Xin-Qi,Jia, Mei,Lin, Yongjia,Cheng, Jun,Xia, Yuanzhi,Ye, Long-Wu
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supporting information
p. 1309 - 1312
(2019/11/26)
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- Copper(II) catalyzed aromatization of tetrahydrocarbazole: An unprecedented protocol and its utility towards the synthesis of carbazole alkaloids
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An efficient protocol for the aromatization of tetrahydrocarbazole is described by using catalytic copper(II) chloride dihydrate in DMSO. This newly established methodology has utilized towards the synthesis of naturally occurring carbazole alkaloids, namely 3-methylcarbazole, 3-formyl carbazole, glycozoline, glycozolicine and clauszoline-K. In addition, the protocol is generalized for the aromatization of N-substituted tetrahydrocarbazole, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydro β-carboline to give the corresponding heteroaromatic compounds from very good to excellent yield. Moreover, this method has been proven to be tolerant to a broad range of functional groups with excellent yields.
- Dalvi, Bhakti A.,Lokhande, Pradeep D.
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supporting information
p. 2145 - 2149
(2018/05/08)
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- Visible-light-promoted intramolecular C-H amination in aqueous solution: Synthesis of carbazoles
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An effective and operationally simple protocol is reported for the synthesis of versatile carbazoles. With water as a co-solvent, visible-light rather than various metals is used to facilitate the conversion of readily available 2-azidobiphenyls under mild conditions. Various functionalized bioactive natural alkaloids, such as glycoborine, clausine C, clausine L, clausine H and clauszoline K, were synthesized efficiently with nitrogen as a sole byproduct. The reaction could be performed in water, acidic or alkaline buffer solutions, showing its potential for applications in biochemistry.
- Yang, Lizheng,Zhang, Yipin,Zou, Xiaodong,Lu, Hongjian,Li, Guigen
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p. 1362 - 1366
(2018/03/26)
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- Photochemical intramolecular amination for the synthesis of heterocycles
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Polycyclic heterocycles can be formed in good to excellent yields via photochemical conversion of the corresponding substituted aryl azides under irradiation with purple LEDs in a continuous flow reactor. The experimental set-up is tolerant to UV-sensitive functional groups while affording diverse carbazoles, as well as an indole and pyrrole framework, in short reaction times. The photochemical method is presumed to progress through a mechanism differing from the other methods of azide activation involving transition metal catalysis.
- Parisien-Collette, Shawn,Cruché, Corentin,Abel-Snape, Xavier,Collins, Shawn K.
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p. 4798 - 4803
(2017/10/23)
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- Preparation of Secondary Phosphine Oxide Ligands through Nucleophilic Attack on Imines and Their Applications in Palladium-Catalyzed Catellani Reactions
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Several new amino-type secondary phosphine oxide (SPO) pre-ligands (3a–3h) that contain P–N bonds were synthesized and characterized. SPOs 3a–3h can tautomerize to phosphinous acids (PA, 3a–3h) as genuine ligands. The formation of SPOs 3a–3h occurred first through nucleophilic attack on the imine carbon atom, then by the addition of RPCl2(R = Ph, Cy, tBu, or iPr), and work-up under acidic conditions. The P–N bond in the newly prepared SPOs is evident from the crystal structures of SPOs 3d and 3h. Reactions of SPOs 3f, 3g, or 3h with Pd(COD)Cl2(COD = cyclooctadiene) yielded palladium complexes 6f, 6g, or 6h. In these crystal structures, PAs 3f, 3g, and 3h act as didentate ligands through P and N donors. Intriguingly, the reaction of SPO 3f with Pd(COD)Cl2also gave rise to palladium complexes 7fa, 7fb, and 8f. The crystal structures of 7fa and 7fb show that the palladium atom is chelated by PA 3f and coordinated by a phosphine-like ligand fragmented from SPO 3f through C–N bond dissociation. Finally, the syntheses of carbazole derivatives were pursued in Catellani reactions with SPOs 3g and 3h as pre-ligands. A mechanism is proposed to account for the catalytic reaction (see the Supporting Information). The optimized conditions for Suzuki reactions using selected SPO ligands are also reported.
- Hu, Chan-Yu,Chen, Ya-Qian,Lin, Guan-Yu,Huang, Ming-Kai,Chang, Yu-Chang,Hong, Fung-E
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supporting information
p. 3131 - 3142
(2016/07/14)
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- Palladium-Catalyzed Intramolecular C–H Amination in Water
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Palladium(II) catalysis was found to be effective for intramolecular C–H amination in water. With 2-azidobiphenyls as substrates, the reaction efficiently provided various carbazoles with N2as the sole byproduct. The reaction showed high functional-group tolerance and could be used in the synthesis of several natural carbazole alkaloids. The catalytic process was promoted by water, and the reaction was inefficient in the organic solvents that were investigated.
- Yang, Lizheng,Li, Hao,Zhang, Haifei,Lu, Hongjian
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p. 5611 - 5615
(2016/12/14)
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- One-pot synthesis of carbazoles via tandem C-C cross-coupling and reductive amination
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We have developed a highly efficient synthetic route to carbazoles that employs sequential C-C/C-N bond formation via Suzuki cross-coupling and Cadogan cyclization using commercially available or easily preparable starting materials. The developed method is compatible with electron neutral, rich or deficient substrates. The synthetic utility of this method was demonstrated by the concise syntheses of four natural products (glycozoline, glycozolicine, glycozolidine and clausenalene).
- Goo, Deuk-Young,Woo, Sang Kook
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supporting information
p. 122 - 130
(2015/12/30)
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- Synthesis of carbazoles by copper-catalyzed intramolecular C-H/N-H coupling
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A Cu-catalyzed intramolecular C-H amination for the synthesis of carbazoles has been developed. The key to success is the installation of the picolinamide-based directing group, which is spontaneously removed after the coupling event. The Cu catalysis proceeded smoothly under Pd- and I(III)-free conditions, and its mild oxidation aptitude enables the rapid and concise construction of heteroatom-incorporated carbazole core π-systems.
- Takamatsu, Kazutaka,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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p. 2892 - 2895
(2014/06/23)
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- A tandem reduction-oxidation protocol for the conversion of 1-keto-1,2,3,4-tetrahydrocarbazoles to carbazoles via tosylhydrazones through microwave assistance: Efficient synthesis of glycozoline, clausenalene, glycozolicine, and deoxycarbazomycin B and the total synthesis of murrayafoline A
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A novel and efficient methodology for the synthesis of carbazoles from 1-keto-1,2,3,4-tetrahydrocarbazoles via the corresponding tosylsulfonhydrazones by a one-pot tandem reduction-oxidation protocol using a combination of NaBH4 and Pd-C on MgSO4·7H2O, a solid support, under microwave is developed. The reaction is successfully extended toward the synthesis of several naturally occurring carbazole alkaloids, namely 3-methylcarbazole, glycozoline, clausenalene, glycozolicine, murrayafoline A, and deoxycarbazomycin B, a carbazole derivative that is known to have a promising antimicrobial activity.
- Chakraborty, Suchandra,Chattopadhyay, Gautam,Saha, Chandan
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- Reactions of arynes with nitrosoarenes - An approach to substituted carbazoles
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No transition metals are necessary in the reaction of in situ generated arynes with nitrosoarenes to give substituted carbazoles. Depending on the fluoride source and the solvent, either N-arylated carbazoles or NH-carbazoles are obtained (see scheme; DME=dimethoxyethane, OTf=trifluoromethanesulfonate). In these cascades a C-C and one or two C-N bonds are formed. The reactions are easy to conduct and proceed under mild conditions. Copyright
- Chakrabarty, Shyamal,Chatterjee, Indranil,Tebben, Ludger,Studer, Armido
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p. 2968 - 2971
(2013/03/29)
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- Recyclable copper catalyzed nitrogenation of biphenyl halides: A direct approach to carbazoles
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A novel A21-CuI catalyzed direct nitrogenation of biphenyl halides for the direct synthesis of carbazoles via a direct C-H amination process has been developed. A recyclable and inexpensive Cu-catalyst was successfully employed in N-heterocyclic compound synthesis via tandem azidation and C-H amination, which makes this protocol very practical and easy to handle.
- Ou, Yang,Jiao, Ning
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supporting information
p. 3473 - 3475
(2013/05/22)
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- Palladium-catalyzed direct synthesis of carbazoles via one-pot N-arylation and oxidative biaryl coupling: Synthesis and mechanistic study
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(Chemical Equation Presented) An efficient catalytic system has been developed for the synthesis of carbazoles by one-pot N-arylation and oxidative biaryl coupling. A significant substituent effect of the diarylamine intermediate on oxidative coupling was observed. Mechanistic studies of oxidative coupling, including trapping of reaction intermediates and kinetic isotope effect experiments, are also presented.
- Watanabe, Toshiaki,Oishi, Shinya,Fujii, Nobutaka,Ohno, Hiroaki
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experimental part
p. 4720 - 4726
(2009/10/02)
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- Palladium-catalyzed direct arylation-based domino synthesis of annulated N-heterocycles using alkenyl or (hetero)aryl 1,2-dihalides
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A palladium-catalyzed reaction sequence consisting of an intermolecular amination and an intramolecular direct arylation enabled highly regioselective syntheses of functionalized indoles or carbazoles and proved to be amenable to the use of inexpensive 1,2dichloroarenes as electrophiles.
- Ackermann, Lutz,Althammer, Andreas,Mayer, Peter
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experimental part
p. 3493 - 3503
(2010/02/28)
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- Reactive 4a-alkyl-4aH-carbazoles by catalytic dearomatisation, and their unusual dimerisation and dealkylation reactions
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Despite their intrinsic instability, 4a-alkyl-4aH-carbazoles can be generated by a catalytic dearomatisation process; their reactivity is demonstrated by facile dealkylation and highly unusual cyclodimerisation processes.
- Bedford, Robin B.,Butts, Craig P.,Haddow, Mairi F.,Osborne, Robert,Sankey, Rosalind F.
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scheme or table
p. 4832 - 4834
(2009/12/08)
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- Rh2(II)-catalyzed synthesis of carbazoles from biaryl azides
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An array of carbazoles (23 examples) can be synthesized from substituted biaryl azides at 60 °C using substoichio-metric quantities of Rh 2(O2CC3F7)4 or Rh 2(O2CC7H15)4.
- Stokes, Benjamin J.,Jovanovic, Brankica,Dong, Huijun,Richert, Kathleen J.,Riell, Ryan D.,Driver, Tom G.
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supporting information; experimental part
p. 3225 - 3228
(2009/08/07)
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- One-pot synthesis of carbazole via tandem Suzuki-Miyaura and amination reaction
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One-pot synthesis of carbazole from two aromatic rings was accomplished by a tandem Suzuki-Miyaura and amination reaction. Our novel phosphine ligand for both reactions efficiently mediates a sequential intermolecular biaryl formation and ring-closing amination. Georg Thieme Verlag Stuttgart.
- Kitamura, Yuki,Yoshikawa, Seiji,Furuta, Takumi,Kan, Toshiyuki
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p. 377 - 380
(2008/04/01)
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- A direct palladium-catalyzed route to selectively substituted carbazoles through sequential C-C and C-N bond formation: Synthesis of carbazomycin A
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The present paper offers a synthetically simple one-pot procedure for the catalytic preparation of the biologically interesting class of carbazoles. The new procedure is based on the combined catalysis of palladium and norbornene starting from o-substituted iodoarenes and N-sulfonylated or N-acetylated o-bromoanilines. A well-known member of this class, carbazomycin A, has been successfully prepared.
- Della Ca', Nicola,Sassi, Giovanni,Catellani, Marta
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supporting information; experimental part
p. 2179 - 2182
(2009/10/02)
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- N-H carbazole synthesis from 2-chloroanilines via consecutive amination and C-H activation
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(Chemical Equation Presented) N-H carbazoles can be produced from 2-chloroanilines and aryl bromides via consecutive catalytic amination and C-H activation. In many instances, this can be done in a tandem manner in one pot. The methodologies developed can be used in the synthesis of a range of carbazoles, including the natural products Clausine P and glycozolidine and a precursor in the synthesis of Clausines H, K, O, and 7-methoxy-O-methylmukonal, and can be extended to the synthesis of indoles.
- Bedford, Robin B.,Betham, Michael
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p. 9403 - 9410
(2007/10/03)
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- Synthesis of carbazoles from o-cyclohex-2-enylanilines
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Several carbazoles (4a-f) have been synthesised from o-cyclohex-2- enylanilines by treatment with pyridine hydrotribromide in methylene chloride at 05 °C for 2 h followed by refluxing with Pd-C in diphenyl ether for 1 h.
- Majumdar,Das,Kundu
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p. 1593 - 1600
(2007/10/03)
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- Reactions of Pyranoindol-3-ones with Dienophiles: Consecutive Cycloaddition/Cycloreversion/1,2 Elimination
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Methylpyranoindol-3-ones 1 react with selected dienophiles (as acetylene equivalents) in a consecutive Diels-Alder/cycloreversion/1,2 elimination reaction sequence to furnish the 1-methyl- and 1,4-dimethylcarbazoles 4.
- Pindur, Ulf,Erfanian-Abdoust, Houshang
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p. 1275 - 1276
(2007/10/02)
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- Improved Syntheses of Substituted Carbazoles and Benzocarbazoles via Lithiation of the (Dialkylamino)methyl (Aminal)Derivatives
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The lithiation of N-carbazoles occurs readily and exclusively at the protonated carbon adjacent to the nitrogen atom.Reaction with a variety of electrophiles produces good to excellent yields of monosubstituted derivatives.Removal of the lithio-directing and nitrogen-protecting function is readily achieved by mild acid-catalyzed hydrolysis during workup of the reaction.Thus, carbazole undergoes lithiation at the 1-position, dibenzocarbazole at the analogous 6-position, and benzocarbazole at both the 6-and 8-positions, with the former predominating. 1,2,3,4-Tetrahydrocarbazole undergoes lithiation at the 8-position, but with 2,3-dimethylindole reaction occurs at the 2-methyl group.Benzocarbazole fails to form an aminal derivative, but on direct lithiation in ether it can be substituted exclusively at the 1-position of the fused benzene ring.
- Katritzky, Alan R.,Rewcastle, Gordon W.,Vazquez de Miguel, Luis M.
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p. 794 - 799
(2007/10/02)
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- Exploratory Routes to Carbazole Derivatives Prelusive to 6H-Pyridocarbazole synthesis.
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Synthetic approaches to 3-acyl substituted carbazoles are explored.Diels-Alder additions of 2-methyl-3-trimethylsilyloxybuta-1,3-diene (7) with crotononitrile or methyl vinyl ketone gave stereoisomeric 5-cyano (or acetyl) 1-methyl-2-trimethylsilyloxy-cyclohex-1-enes.The former were readily hydrolysed to the corresponding cyclohexanones which failed to undergo Borsche cyclisation under the conditions used.The latter were reduced and then hydrolysed to a stereoisomeric mixture of 4-(1-hydroxyethyl)-2-methyl- cyclohexanones (14).The Borsche cyclisation of (14) with phenylhydrazine was attempted under a wide variety of conditions followed by attempted dehydrogenation of the intermediate tetrahydrocarbazoles with chloranil, but loss of the hydroxyethyl side chain took place giving 1-methylcarbazole as the sole isolable carbazole.In the second approach a number of N-acyl substituted diphenylamines are synthesised by the Goldberg reaction.Those lacking a 4-substituent undergo a photo-anilide rearrangement which is accompanied by carbazole formation.Diphenylamides with a 4- substituent, after hydrolysis to the diphenylamines, undergo photochemical cyclisation to 3- carbazoles but in low yield.The Goldberg synthesis of 4-formyldiphenylamides affords substantial amounts of the 4-formyldiphenylamines after work-up.These, on reaction with palladium(II) acetate in acetic acid give a mixture of products including the required 3-formyl (or carboxyl) carbazoles.
- Hewlins, Michael J. E.,Jackson, Anthony H.,Long, Anthony,Oliveira-Campos, Ana,Shannon, Patrick V. R.
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p. 2645 - 2696
(2007/10/02)
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- One-step Conversion of Oxotetrahydrocarbazole into Carbazole
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Oxotetrahydrocarbazoles (Ia-e) when heated with a 1:1 mixture of KOH + NaOH furnish the corresponding carbazoles (IIa-e) in good yields (ca. 80percent).The method appears to be of general applicability.
- Bhattacharyya, P.,Jash, S. S.
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- Generation and Rearrangement of 4aH-carbazoles
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The benzotriazoles (12a-c) bearing ortho-blocked 1-aryl substituents have been decomposed thermally by flash vacuum pyrolysis, and photochemically by irradiation in acetonitrile at 254 nm.The pyrolyses are complex giving mainly mono- and di-methylcarbazoles from (12a), di- and trimethylcarbazoles from (12b), and a tetra- and a penta-methylcarbazole from (12c).All of these products could be formed by generation of 4aH-carbazole intermediates (24) with subsequent thermally-allowed sigmatropic rearrangements (Scheme 6).The photolyses give a different set of products consisting mainly of the cyclopentaquinolines (27a-c) from (12a-c), respectively.These products could be formed from the same 4aH-carbazoles (24) which now undergo photochemical, aza-di-?-methane, rearrangements to give intermediates (29) and hence products (27) (Scheme 7).The 4a-methyl intermediate (29c) is intercepted as the adduct (30) in an extended cycloaddition reaction with acrylonitrile.Key reaction products were synthesized by independent methods.
- Kulagowski, Janusz J.,Moody, Christopher J.,Rees, Charles W.
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p. 2725 - 2732
(2007/10/02)
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- The Pyrolysis of 2-Azidobenzoates. A New Synthesis of Carbazoles and Other N-Heterocycles
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The spray pyrolysis of aryl 2-azidobenzoates yields carbazoles, involving a rearrangement whereby the nitrogen of the product is attached to the aryl 1-carbon, a process involving a spiro 6-membered intermediate.When the aryl ortho-positions were both alkyl substituted the product was ab acridan instead.With an ortho-carboxylate, acridone formation competed with that of carbazole.When the CO-O group of the substrate was replaced by O-CO, CO-S, CO-NPh, or SO2-O the pyrolysis was ineffective.Benzyl 2-azidobenzoates, however, pyrolysed to yield 1-benzyl-2,1-benzisoxazolones by an unprecedented C-O insertion reaction of the intermediate nitrene.
- Clancy, Michael G.,Hesabi, Massoud M.,Meth-Cohn, Otto
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p. 429 - 434
(2007/10/02)
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- Generation and Rearrangement of 4aH-Carbazoles
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Thermal and photochemical decomposition of benzotriazoles (3) gives carbazoles (4) and (5), and cyclopentaquinolines (6), the formation of these products being rationalised by rearrangements in 4aH-carbazole intermediates (7); one proposed intermediate (11c) has been intercepted in an extended cycloaddition reaction with acrylonitrile.
- Kulagowski, Janusz J.,Moody, Christopher J.,Rees, Charles W.
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p. 548 - 550
(2007/10/02)
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- Synthesis of Girinimbine Isomers - Pyranocarbazole Derivatives
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Title compounds (XIV), isomeric with girinimbine (I), have been synthesized.Aromatization of 1-oxo-1,2,3,4-tetrahydrocarbazoles (VIII) in diphenyl ether in the presence of 5percent Pd/C gives 1-hydroxycarbazole derivatives (IX).Condensation of IX with 3,3-dimethylacrylic acid affords indolochromanones (XI) which are reduced to the corresponding alcohols (XIII) by NaBH4.In situ elimination of the tosylate of XIII yields the requisite pyranocarbazole derivatives (XIV).During the formation of XI from IX, the corresponding C-acylated products, 2-acryloyl-1-hydroxycarbazoles (XII) have been isolated.XII are shown to be intermediates during the formation of XI as these (XII) could be converted into XI.The condition for the reaction IX -> XI has been optimised.
- Patel, B. P. J.
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- The Chemistry of Carbazoles. VII. Syntheses of Methylcarbazoles
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Thirty-six methylcarbazoles were prepared, and their synthetic methods were critically described.
- Kuroki, Masanate,Tsunashima, Yutaka
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p. 709 - 714
(2007/10/02)
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- "1,4" Alkyl Migrations in Fischer Indole Cyclizations
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The product from Fisher indole cyclization and dehydrogenation of cyclohexanone 2,4,6-trimethylphenylhydrazone (1) was determined to be 2,3,4-trimethylcarbazole (3) resulting from a formal 1,4-methyl migration, as previously proposed.To determine the destinations of migrating groups in these rearrangements, the Fischer indole cyclization and dehydrogenation of cyclohexanone 2-ethyl-6-methylphenylhydrazone (17) were studied.The products obtained were 1-ethylcarbazole, 1-methylcarbazole, 2-ethyl-1-methylcarbazole (18), and an apparent mixture of 1-ethyl-4-methylcarbazole (21) and 4-ethyl-1-methylcarbazole (22).However, no 1-ethyl-2-methylcarbazole (19), which would have been obtained by a "1,4"-methyl migration, was obtained.Analysis of the product ratios suggested that the apparent ethyl shift in formation of 18 actually proceeded by a formal shift of either an ethyl or a methyl group, followed by a ethyl shift.Cyclization of 3-pentanone 2,4,6-trimethylphenylhydrazone (26) proceeded to give the product of "1,4" methyl migration, demonstrating that such reactions can occur with phenylhydrazones of ketones other than cyclohexanone.It is proposed that steric factors play a major role in determining whether migrating groups undergo or "1,4" shifts during Fischer indole cyclizations.
- Miller, Bernard,Matjeka, Edward R.
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p. 4772 - 4780
(2007/10/02)
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3,4-Dihydrocarbazol-(2H)-1-ones are transformed by boiling pyridine hydrochloride into corresponding carbazoles.
- Bisagni, Emile,Ducrocq, Claire,Hung, Nguyen Chi
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p. 1327 - 1330
(2007/10/02)
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