Synthesis of Pyrrole-Fused <i>C</i>,<i>N</i>-Cyclic Azomethine Imines and Pyrazolopyrrolopyrazines: Analysis of Their Aromaticity Using Nucleus-Independent Chemical Shifts Values

Özer, Merve Sinem; Mengeş, Nurettin; Keskin, Selbi; Şahin, Ertan; Balcı, Metin

doi:10.1021/acs.orglett.5b03434

Cited by 23 publications

(6 citation statements)

References 66 publications

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“…Initially, based on our previous works on the synthesis of azaheterocyclic compounds, [15] we chose N ‐propargyl‐C‐2‐substituted‐pyrroles as the starting material, synthesized as described in our previous report [16a–e] . Reaction of 13a with a base provided the indolizine derivative 15a in relatively good yield beside the allene 16 and the hydrolysis compound 17 .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

et al. 2021

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Ten different N‐propargyl pyrrole derivatives having various substituents at the C‐2 position were synthesized. These derivatives were converted into indolizine derivatives by the [2+2] cycloaddition reaction of pyrrole N‐allene, forming in situ, by heating in PrOH in basic medium. The structures were characterized by NMR and X‐ray crystallography. The N‐propargylated derivatives smoothly underwent intermolecular cyclizations to produce indolizine derivatives in good yields. We proposed a radical mechanism for the dimerization. Reaction of an allene product with butylated hydroxytoluene (BHT), a radical scavenger, did not give any dimerization product. This result supports the radical reaction.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

et al. 2021

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“…4` b c d For example, Özer and co-workers reported that the reaction of pyrrole hydrazones having an N -propargyl group with different dipolarophiles in the presence of catalytic amounts of silver triflate or gold(III) chloride afforded the corresponding cycloadducts with a pyrazolopyrrolopyrazine skeleton via sequential 1,3-dipolar cycloaddition and intramolecular rearrangement. 4e The use of DMAD in the silver(I)-catalyzed sequential reaction of N ′-(2-alkynylbenzylidene)hydrazides ( I ) led to the preparation of the corresponding ( Z )-2-(isoquinolin-2-ium-2-yl)-1,4-dimethoxy-1,4-dioxo-3-(tosylimino)butan-2-ide derivatives ( II ) (Scheme 1 ). This transformation required a three-step reaction involving 6- endo -cyclization, cycloaddition, and intramolecular rearrangement.…”

Section: Table 1 Optimization Of the Reaction Condition...mentioning

confidence: 99%

NIS-Mediated Oxidation of Hydrazones: A Rapid Access to Fused Lactones and Tosylhydrazides

Takallou

Al-Shidhani

Al-Siyabi

et al. 2023

Synlett

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A tandem one-pot strategy for the synthesis of 4-iodo-3-aryl(alkyl)-1H-pyrano[4,3-b]quinolin-1-ones and (E)-3-(iodo(phenyl)methylene)isobenzofuran-1(3H)-ones from 2-alkynylhydrazones is developed through oxidation and regioselective 6-endo- and 5-exo-iodocyclization pathways using NIS as an iodinating reagent. This approach tolerates a variety of in-situ generated alkynyl containing tosylhydrazones and affords the corresponding products in high yields. This protocol has also been applied for the synthesis of different derivatives in good to excellent yields.

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“…Recently, we developed new synthetic methodologies for the synthesis of various pyrrole-fused new heterocycles using alkyne cyclization reactions [15–22]. In this article, we demonstrate for the first time the concept of the cyclization of N- alkyne-substituted pyrrole esters 7 (Fig.…”

Section: Introductionmentioning

confidence: 98%

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

Yenice¹,

Başçeken²,

Balcı³

2017

Beilstein J. Org. Chem.

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Intramolecular nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole esters is described. Efficient routes towards the synthesis of pyrrolopyrazinone, pyrrolotriazinone and pyrrolooxazinone have been developed. First, N-alkyne-substituted pyrrole ester derivatives were synthesized. Introduction of various substituents into the alkyne functionality was accomplished by a copper-catalyzed cross-coupling reaction. Nucleophilic cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with hydrazine afforded the 6-exo-dig/6-endo-dig cyclization products depending on the electronic nature of the substituents attached to the alkyne. On the other hand, cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with iodine only resulted in the formation of the 6-endo-dig cyclization product regardless of the substitution of the alkyne functionality.

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Synthesis of Pyrrole-Fused C,N-Cyclic Azomethine Imines and Pyrazolopyrrolopyrazines: Analysis of Their Aromaticity Using Nucleus-Independent Chemical Shifts Values

Cited by 23 publications

References 66 publications

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

Synthesis of Indolizines by Dimerization of N‐Propargylated Pyrroles via Allene Intermediates

NIS-Mediated Oxidation of Hydrazones: A Rapid Access to Fused Lactones and Tosylhydrazides

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

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