Catalyst free cyclocondensation of β-ethylthio-β-indolyl-α, β-unsaturated ketones with hydrazines: Efficient synthesis of 3-pyrazolyl indoles

Yu, Haifeng; Wang, Wenju

doi:10.1080/00397911.2019.1681001

Cited by 10 publications

(1 citation statement)

References 41 publications

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“…A variety of N-unsubstituted pyrazoles bearing indole units have been synthesized from the cyclocondensation reaction of β-ethyltho-β-indolyl-α, β-unsaturated ketones and hydrazine hydrate or semicarbazide Considering the importance of pyrazoles, our recent research interests have focused on the synthesis of pyrazoles. A variety of N-unsubstituted pyrazoles bearing indole units have been synthesized from the cyclocondensation reaction of β-ethyltho-β-indolyl-α, β-unsaturated ketones and hydrazine hydrate or semicarbazide hydrochlorides as a hydrazine equivalent in organic solvent or water [31][32][33]. Furthermore, by controlling the reaction conditions, the regioselective synthesis of isomeric 3-(1-substituted pyrazol-3(5)yl) indoles was also successfully realized when βethyltho-β-indolyl-α, β-unsaturated ketones reacted with monosubstituted hydrazines [34].…”

Section: Introductionmentioning

confidence: 99%

Regio- and Stereoselective Switchable Synthesis of (E)- and (Z)-N-Carbonylvinylated Pyrazoles

Zhang

et al. 2023

Molecules

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Regio- and stereoselective switchable synthesis of (E)- and (Z)-N-carbonylvinylated pyrazoles is first developed by using the Michael addition reaction of pyrazoles and conjugated carbonyl alkynes. Ag2CO3 plays a key role in the switchable synthesis of (E)- and (Z)-N-carbonylvinylated pyrazoles. Ag2CO3-free reactions lead to thermodynamically stable (E)-N-carbonylvinylated pyrazoles in excellent yields whereas reactions with Ag2CO3 give (Z)-N-carbonylvinylated pyrazoles in good yields. It is noteworthy that (E)- or (Z)-N1-carbonylvinylated pyrazoles are obtained with high regioselectivity when asymmetrically substituted pyrazoles react with conjugated carbonyl alkynes. The method can also extend to the gram scale. A plausible mechanism is proposed on the basis of the detailed studies, wherein Ag+ acts as coordination guidance.

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Section: Introductionmentioning

confidence: 99%

Regio- and Stereoselective Switchable Synthesis of (E)- and (Z)-N-Carbonylvinylated Pyrazoles

Zhang

et al. 2023

Molecules

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Recent Developments in the Synthesis of Indole‐Pyrazole Hybrids

et al. 2022

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Indole and pyrazole are two important scaffolds in the field of medicinal chemistry. Compounds bearing indole and/or pyrazole moiety have been extensively investigated for a wide range of biological applications. Of them, compounds containing both indole and pyrazole moieties (also termed as indole‐pyrazole hybrids) are of particular interest since synergistic pharmacological activities may be gained comparing to those with each individual pharmacophore. Indole‐pyrazole hybrids can be classified into two general classes of direct‐linked hybrids and spacer‐linked hybrids. For each class, it can be sub‐divided into indole‐C2 pyrazole hybrids, indole‐C3 pyrazole hybrids and indole‐C4/5/6/7 pyrazole hybrids based on the substitution position of pyrazole on the indole moiety. Many types of indole‐pyrazole hybrids have been reported with good antimicrobial, anticancer, antitumor, anti‐inflammatory, anti‐oxidant activities etc. However, no papers have been noted to comprehensively summarize the chemical synthesis of these important indole‐pyrazole hybrids as bioactive compounds except for a few reviews focusing on the synthesis of each individual indole‐ and pyrazole‐containing derivatives. Thus, we here present a comprehensive and updated review focusing on the progress of chemical synthesis of all types of indole‐pyrazole hybrids in order to provide a better understanding of the indole‐pyrazole hybrids to researchers in the fields of synthetic chemistry and to facilitating drug development.

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A new and efficient approach to 2-hydroxybenzophenone derivatives via [5C + 1C] annulation of α-alkenoyl-α-aroyl ketene dithioacetals and nitroalkanes

Zhao

Wang

et al. 2021

Tetrahedron

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Catalyst free cyclocondensation of β-ethylthio-β-indolyl-α, β-unsaturated ketones with hydrazines: Efficient synthesis of 3-pyrazolyl indoles

Cited by 10 publications

References 41 publications

Regio- and Stereoselective Switchable Synthesis of (E)- and (Z)-N-Carbonylvinylated Pyrazoles

Regio- and Stereoselective Switchable Synthesis of (E)- and (Z)-N-Carbonylvinylated Pyrazoles

Recent Developments in the Synthesis of Indole‐Pyrazole Hybrids

A new and efficient approach to 2-hydroxybenzophenone derivatives via [5C + 1C] annulation of α-alkenoyl-α-aroyl ketene dithioacetals and nitroalkanes

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