Base-Mediated Hydroamination of Propargylamine: A Regioselective Intramolecular 5-<i>exo-dig</i> Cycloisomerization en Route to Imidazole-2-thione

Ranjan, Alok; Yerande, Ragini; Wakchaure, Prasad B.; Yerande, Swapnil G.; Dethe, Dattatraya H.

doi:10.1021/ol502871r

Cited by 64 publications

(32 citation statements)

References 48 publications

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“…Earlier we reported that, in the presence of base, propargylamine reacts with isothiocyanate, and hydroamination product imidazolidine‐2‐thione 5a is exclusively formed . But under the current optimized solvent‐free conditions, hydrothiolation product thiazolidine 4a was exclusively formed through not isolated propargylthiourea intermediate 3a .…”

Section: Resultsmentioning

confidence: 79%

Thiol–Yne Coupling of Propargylamine under Solvent‐Free Conditions by Bond Anion Relay Chemistry: An Efficient Synthesis of Thiazolidin‐2‐ylideneamine

et al. 2017

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Thiol–yne coupling of propargylamine with isothiocyanate has been developed under metal‐ and solvent‐free conditions. The addition of propargylamine to isothiocyanate gives propargylthiourea. This intermediate in situ undergoes intramolecular 5‐exo‐dig cyclization to give thiazolidin‐2‐ylideneamine. A through‐bond anion relay reaction occurs by attack of the sulfur (not the nitrogen) atom on the alkyne in a highly regioselective manner at ambient temperature. Wide varieties of thiazolidin‐2‐ylideneamine derivatives were formed in excellent yields.

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Section: Resultsmentioning

confidence: 79%

Thiol–Yne Coupling of Propargylamine under Solvent‐Free Conditions by Bond Anion Relay Chemistry: An Efficient Synthesis of Thiazolidin‐2‐ylideneamine

et al. 2017

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“…[8] Various nitrogen-and sulfur-containing heterocycles have been synthesized from isothiocyanate substrates. [9] In particular, o-alkynylphenyl isothiocyanates have been used to construct fused-ring compounds via cascade reactions, [10] which show higher overall efficiency than traditional stepwise syntheses because multiple CÀC and CÀX bonds can be formed in one pot. [11] For example, in 2014, Cai et al reported the formation of 5H-benzo [d]imidazo [5,1-b] [1,3]thiazines by means of copper-catalyzed [3 + 2] cascade cycloaddition reactions between o-alkynylphenyl isothiocyanates and isocyanides (Scheme 1a).…”

Section: Abstract: Biologically Active; Copper; Cyclization; Heterocymentioning

confidence: 99%

One‐Pot Copper‐Catalyzed Cascade Bicyclization Strategy for Synthesis of 2‐(1H‐Indol‐1‐yl)‐4,5‐dihydrothiazoles and 2‐(1H‐Indol‐1‐yl)thiazol‐5‐yl Aryl Ketones with Molecular Oxygen as an Oxygen Source

et al. 2018

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An atom-economical method for synthesizing N-heterocyclic indoles from readily available o-alkynylphenyl isothiocyanates and propargylamine derivatives is reported. This method involves a copper-catalyzed cascade bicyclization process consisting of an intramolecular 5-exo-dig hydrothiolation reaction and an intramolecular hydroamination reaction and, depending on whether or not molecular oxygen is present, selectively affords Z-isomers of 2-(1H-indol-1-yl)-4,5-dihydrothiazoles or 2-(1H-indol-1-yl)thiazol-5-yl aryl ketones in satisfactory yields. Mechanistic studies indicate that molecular oxygen acts as the oxygen source for the ketone moiety in the products.

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“…The steric and electronic effects of the phenyl ring substituents on the propargylamine ( 38 ) backbone affected the selectivity of the reaction (Table ). The reaction of compound 38 (R 1 =Ph) with different isothiocyanates ( 35 ) resulted in the imidazole thione derivatives ( 41) as a sole product in moderate yield …”

Section: Synthesis Of Thiazolesmentioning

confidence: 99%

An Overview of Recent Developments in the Synthesis of Substituted Thiazoles

et al. 2020

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Thiazole frame work represents a vital pharmacophore in several areas of chemistry. Consequently, several synthetic protocols to construct and functionalize this core, in an attempt to generate diverse thiazole containing architectures have been developed by various researchers across the globe. These wide range of methodologies developed will allow the access to fully decorated thiazole containing new chemical entities that can find various application in the field of medicinal chemistry, agrochemicals and material science. This review will provide an insight in to the various synthons used in construction and diversification of this core. Diversely functionalized thiazole analogs are considered as a vital azole framework present in many natural products. This prominent heterocycle also constitutes an important pharmacophore in medicinal chemistry, in agrochemicals and in molecules for material science applications. All these above‐mentioned features of thiazole necessitates the continuous development of efficient methods to access this heterocycle. Accordingly, various researchers across the globe have come up with efficient synthetic protocols in an attempt functionalize different positions of this important scaffold. This review aims at highlighting some of the latest synthetic approaches to di/tri‐substituted thiazole analogs which are known to possess a wide spectrum of biological activities.

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Base-Mediated Hydroamination of Propargylamine: A Regioselective Intramolecular 5-exo-dig Cycloisomerization en Route to Imidazole-2-thione

Cited by 64 publications

References 48 publications

Thiol–Yne Coupling of Propargylamine under Solvent‐Free Conditions by Bond Anion Relay Chemistry: An Efficient Synthesis of Thiazolidin‐2‐ylideneamine

Thiol–Yne Coupling of Propargylamine under Solvent‐Free Conditions by Bond Anion Relay Chemistry: An Efficient Synthesis of Thiazolidin‐2‐ylideneamine

One‐Pot Copper‐Catalyzed Cascade Bicyclization Strategy for Synthesis of 2‐(1H‐Indol‐1‐yl)‐4,5‐dihydrothiazoles and 2‐(1H‐Indol‐1‐yl)thiazol‐5‐yl Aryl Ketones with Molecular Oxygen as an Oxygen Source

An Overview of Recent Developments in the Synthesis of Substituted Thiazoles

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