Update on the Synthesis of N‐Heterocycles via Cyclization of Hydrazones (2017–2021)

Lv, Yunhe; Meng, Jianping; Li, Chen; Wang, Xin; Ye, Yong; Sun, Kai

doi:10.1002/adsc.202101184

Cited by 52 publications

(17 citation statements)

References 139 publications

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“…It must been noted that α,β-alkynic hydrazones are an important class with practical value, they have been emanated as powerful synthons for constructing diverge ranges of cyclic compounds through transition metal catalyzed or transition metal free reactions [ 47 , 48 , 49 ].…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Anti-Inflammatory Spirostene-Pyrazole Conjugates by a Consecutive Multicomponent Reaction of Diosgenin with Oxalyl Chloride, Arylalkynes and Hydrazines or Hydrazones

et al. 2021

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Steroid sapogenin diosgenin is of significant interest due to its biological activity and synthetic application. A consecutive one-pot reaction of diosgenin, oxalyl chloride, arylacetylenes, and phenylhydrazine give rise to steroidal 1,3,5-trisubstituted pyrazoles (isolated yield 46–60%) when the Stephens–Castro reaction and heterocyclization steps were carried out by heating in benzene. When the cyclization step of alkyndione with phenylhydrazine was performed in 2-methoxyethanol at room temperature, steroidal α,β-alkynyl (E)- and (Z)-hydrazones were isolated along with 1,3,5-trisubstituted pyrazole and the isomeric 2,3,5-trisubstituted pyrazole. The consecutive reaction of diosgenin, oxalyl chloride, phenylacetylene and benzoic acid hydrazides efficiently forms steroidal 1-benzoyl-5-hydroxy-3-phenylpyrazolines. The structure of new compounds was unambiguously corroborated by comprehensive NMR spectroscopy, mass-spectrometry, and X-ray structure analyses. Performing the heterocyclization step of ynedione with hydrazine monohydrate in 2-methoxyethanol allowed the synthesis of 5-phenyl substituted steroidal pyrazole, which was found to exhibit high anti-inflammatory activity, comparable to that of diclofenac sodium, a commercial pain reliever. It was shown by molecular docking that the new derivatives are incorporated into the binding site of the protein Keap1 Kelch-domain by their alkynylhydrazone or pyrazole substituent with the formation of more non-covalent bonds and have higher affinity than the initial spirostene core.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Anti-Inflammatory Spirostene-Pyrazole Conjugates by a Consecutive Multicomponent Reaction of Diosgenin with Oxalyl Chloride, Arylalkynes and Hydrazines or Hydrazones

et al. 2021

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“…On the other hand, heterocyclic chemistry is one of the most sought out areas of organic chemistry research [23][24][25][26]. Heterocycles have been primarily used in many bioactive compounds [27].…”

Section: Introductionmentioning

confidence: 99%

Chalcones: Versatile intermediates in heterocyclic synthesis

Nayak

Gaonkar

Sabu

2023

Journal of Heterocyclic Chem

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Chalcones are a fascinating and well‐studied group of organic molecules. Synthesis of chalcones has been one of the essential areas of organic synthesis over the last few decades because of their immense therapeutic and excellent photophysical properties. Furthermore, these chalcone derivatives can be utilized to make a variety of heterocyclic compounds, especially five‐ and six‐membered heterocycles. Heterocyclic compounds have a long history in chemistry, primarily in pharmaceuticals. However, synthesizing some specific heterocyclic molecules remains challenging and requires multistep processes with few possible intermediates. Chalcones can be considered as one of the most useful, readily available intermediates in heterocyclic synthesis. Herein, the synthesis of various potential heterocyclic compounds using chalcones as an intermediate is elaborated. This review shows the untapped potential of chalcones in organic synthesis. Also, it will assist the chemist in designing new heterocycles by adopting these strategies.

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“…While there are some literature reviews of the synthetic strategies that may be applied in the preparation of pyrazolines, [7a,b] there is not a single, comprehensive review article covering all synthetic aspects and advancements in this growing field. As a subclass of pyrazolines, spirocyclic derivatives have been described previously [7c] . The conventional methods have also been described adequately [6b] .…”

Section: Introductionmentioning

confidence: 99%

Strategies and Methods for the Synthesis of 2‐Pyrazolines: Recent Developments (2012–2022)

Matiadis

2023

Adv Synth Catal

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2‐Pyrazolines are important five‐membered heterocycles, containing two adjacent nitrogen atoms. They can incorporate various functional groups and possess unique biological properties. Moreover, they have been used as useful building blocks. In recent years, the field of 2‐pyrazoline synthesis has experienced enormous progress. Novel strategies have been developed, and many studies reporting improvements or adaptations of existing protocols have been published, giving access to new functionalizations, unexplored structures, and/or enantioselective synthesis. This review summarizes the progress made in synthetic methodologies during the period from 2012 to 2022. The functionalization challenges and capabilities, scopes and limitations of the reactions, substitution patterns, and mechanisms of the reactions, where appropriate, will be discussed.

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Update on the Synthesis of N‐Heterocycles via Cyclization of Hydrazones (2017–2021)

Cited by 52 publications

References 139 publications

Synthesis of Anti-Inflammatory Spirostene-Pyrazole Conjugates by a Consecutive Multicomponent Reaction of Diosgenin with Oxalyl Chloride, Arylalkynes and Hydrazines or Hydrazones

Synthesis of Anti-Inflammatory Spirostene-Pyrazole Conjugates by a Consecutive Multicomponent Reaction of Diosgenin with Oxalyl Chloride, Arylalkynes and Hydrazines or Hydrazones

Chalcones: Versatile intermediates in heterocyclic synthesis

Strategies and Methods for the Synthesis of 2‐Pyrazolines: Recent Developments (2012–2022)

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