Ligand-free Cu2O-catalyzed cross coupling of nitrogen heterocycles with iodopyridines

Teo, Yong‐Chua; Yong, Fui-Fong; Sim, Shirlyn

doi:10.1016/j.tet.2013.06.095

Cited by 33 publications

(17 citation statements)

References 32 publications

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“…In order to test the functionalization of the above synthesized aryl iodides through a subsequent transition-metal-catalyzed coupling reaction we subjected three of them to a copper-catalyzed N-arylation reaction. Thus, the iodides 3b , 3d and 4d were reacted with 2 equiv of imidazole in the presence of 0.1 equiv of copper(I) oxide, 2 equiv of caesium carbonate as the base in dimethylsulfoxide (DMSO) at 110 °C [ 47 ]. Under these conditions, the imidazole-substituted compounds 5b , 5d and 6d were generated in 85, 67 and 40% yield, respectively ( Scheme 8 , Fig.…”

Section: Resultsmentioning

confidence: 99%

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Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

Messaoud¹,

Bentabed‐Ababsa²,

Hedidi³

et al. 2015

Beilstein J. Org. Chem.

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SummaryThe synthesis of N-arylated pyrroles and indoles is documented, as well as their functionalization by deprotonative metallation using the base in situ prepared from LiTMP and ZnCl2·TMEDA (1/3 equiv). With N-phenylpyrrole and -indole, the reactions were carried out in hexane containing TMEDA which regioselectively afforded the 2-iodo derivatives after subsequent iodolysis. With pyrroles and indoles bearing N-substituents such as 2-thienyl, 3-pyridyl, 4-methoxyphenyl and 4-bromophenyl, the reactions all took place on the substituent, at the position either adjacent to the heteroatom (S, N) or ortho to the heteroatom-containing substituent (OMe, Br). The CH acidities of the substrates were determined in THF solution using the DFT B3LYP method in order to rationalize the experimental results.

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Section: Resultsmentioning

confidence: 99%

“…Procedure 7 for the N-arylation of imidazole [ 47 ] . A mixture of the prepared iodide (1.0 mmol), Cu 2 O (0.10 g, 0.10 mmol), Cs 2 CO 3 (0.65 g, 2.0 mmol), imidazole (0.14 g, 2.0 mmol) and DMSO (0.5 mL) was stirred for 24 h at 110 °C under argon.…”

Section: Methodsmentioning

confidence: 99%

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

Messaoud¹,

Bentabed‐Ababsa²,

Hedidi³

et al. 2015

Beilstein J. Org. Chem.

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“…To take advantage of the iodo group on 2b-I , C-N bond formation with azoles was attempted under copper catalysis as reported previously [41,42] (Table 4). Thus, by treating 2b-I with pyrrole (entry 1; see Figure 1), indole (entry 2), pyrazole (entry 3), imidazole (entry 4) or 1,2,4-triazole (entry 5), in the presence of catalytic copper(I) oxide, cesium carbonate, and dimethylsulfoxide (DMSO) at 110 °C for 24 h, the expected N -arylated azoles were obtained in 51 to 79% yields.…”

Section: Resultsmentioning

confidence: 99%

From Quinoxaline, Pyrido[2,3-b]pyrazine and Pyrido[3,4-b]pyrazine to Pyrazino-Fused Carbazoles and Carbolines

et al. 2018

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2,3-Diphenylated quinoxaline, pyrido[2,3-b]pyrazine and 8-bromopyrido[3,4-b]pyrazine were halogenated in deprotometalation-trapping reactions using mixed 2,2,6,6-tetramethyl piperidino-based lithium-zinc combinations in tetrahydrofuran. The 2,3-diphenylated 5-iodo- quinoxaline, 8-iodopyrido[2,3-b]pyrazine and 8-bromo-7-iodopyrido[3,4-b]pyrazine thus obtained were subjected to palladium-catalyzed couplings with arylboronic acids or anilines, and possible subsequent cyclizations to afford the corresponding pyrazino[2,3-a]carbazole, pyrazino[2′,3′:5,6] pyrido[4,3-b]indole and pyrazino[2′,3′:4,5]pyrido[2,3-d]indole, respectively. 8-Iodopyrido[2,3-b] pyrazine was subjected either to a copper-catalyzed C-N bond formation with azoles, or to direct substitution to introduce alkylamino, benzylamino, hydrazine and aryloxy groups at the 8 position. The 8-hydrazino product was converted into aryl hydrazones. Most of the compounds were evaluated for their biological properties (antiproliferative activity in A2058 melanoma cells and disease-relevant kinase inhibition).

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“…[78] Two years later, the same group again reported ligand-free N-1 heteroarylation of 1H-indazole (13 a) using Cu 2 O as a catalyst, Cs 2 CO 3 as a base in DMSO at 100°C for 24 h. The desired N-1 heteroarylated 1Hindazole product (13 b) was formed with 90% yield (Scheme 13). [79] Guillaumet's group reported an efficient and facile method for direct C-3 arylation of 1H-indazoles (14 a) using aryl iodide or bromide as a coupling partner, Pd (OAc) 2 as a catalyst, 1,10-phenanthroline as a ligand, K 2 CO 3 as base and DMA as the solvent. The desired C-3 arylated 1H-indazole (14 b) was obtained with good yield (Scheme 14).…”

Section: Arylationmentioning

confidence: 99%

Direct Catalytic Functionalization of Indazole Derivatives

2020

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Indazoles are a very important class of N‐containing heterocycles with a wide range of biological and medicinal properties. The presence of different functionalities on indazole moieties enhances its biological activities. Hence, the preparation of indazole compounds bearing functional groups has gained a significant interest to the organic synthetic chemists. A large effort has been made to develop efficient and new methods for the functionalization of indazoles. Direct catalytic functionalization is a very powerful tool for facile synthesis of important indazole derivatives due to its straightforwardness. This review summarizes developments on direct functionalizations of indazoles published in the last two decades.

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Ligand-free Cu2O-catalyzed cross coupling of nitrogen heterocycles with iodopyridines

Cited by 33 publications

References 32 publications

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

From Quinoxaline, Pyrido[2,3-b]pyrazine and Pyrido[3,4-b]pyrazine to Pyrazino-Fused Carbazoles and Carbolines

Direct Catalytic Functionalization of Indazole Derivatives

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