Brønsted Acid Catalyzed (3+2)‐Cycloaddition of Thioketones and Indole‐2‐Carbinols Toward Thiazolo[3,4‐a]indoles

Sachse, Florian; Schneider, Christoph

doi:10.1002/adsc.202101168

Cited by 9 publications

(4 citation statements)

References 49 publications

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“…When incorporated into indole derivatives, this combination not only introduces structural diversity but also often results in compounds with enhanced bioactivity. The 2-aryl-4H- [1,3]thiazolo [4,5-b] a class of compounds that hold great potential for the medicinal applications, unveiling a balance between synthetic accessibility and biological relevance [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Antimicrobial Activity and Molecular Docking of Some Novel 2-Aryl-4H-[1,3]-thiazolo[4,5-b]indoles

Bhargavi Posinasetty,

Kumarachari,

Chitrapu

et al. 2024

ajc

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In present study, six novel 2-aryl-4H-[1,3]-thiazolo[4,5-b]indoles (4a-f) were synthesized by integrating thiazole and indole motifs through a three-component one-pot condensation involving isatin, ammonium thiocyanate and arylaldehydes. Structural confirmation was achieved using IR, 1H NMR and mass spectrometric techniques. Molecular targets, bioactivity scores, drug-likeness, anti- tuberculosis and antibacterial properties and toxicity were all predicted using various computational techniques. To calculate binding affinities to Mycobacterium tuberculosis enoyl-ACP reductase and Escherichia coli Topoisomerase IV, in vitro bioactivity studies were performed and Schrödinger docking simulations were performed. Anti-tubercular efficacy was evaluated using the MABA method, while antibacterial effectiveness against both Gram-positive and Gram-negative bacteria was assessed through the agar plate method. The results highlight the potential of these heterocyclic molecular hybrids, positioning them as promising candidates for further lead optimization in the development of more potent and safer pharmaceutical agents.

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Section: Introductionmentioning

confidence: 99%

Synthesis, Antimicrobial Activity and Molecular Docking of Some Novel 2-Aryl-4H-[1,3]-thiazolo[4,5-b]indoles

Bhargavi Posinasetty,

Kumarachari,

Chitrapu

et al. 2024

ajc

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“…In this context, indolylmethanols have been recognized as versatile platform molecules for a variety of transformations, and their involved reactions have provided efficient methods for the synthesis of indole-based heterocycles. − Particularly, 2-indolylmethanol has exhibited great potential in the synthesis of indole derivatives and construction of indole-fused rings based on its unique property of C3-umpolung under the catalysis of Brønsted acid (B–H) (Scheme a). ,, Specifically, in the presence of B–H, 2-indolylmethanol undergoes dehydration to generate a series of carbocation, vinyliminium, and delocalized carbocation intermediates exhibiting C3-electrophilicity, thus undergoing regioselective substitutions and (3+n) cycloadditions , to generate indole derivatives and indole-fused rings.…”

Section: Introductionmentioning

confidence: 99%

Cooperative Catalysis-Enabled (4 + 3) Cycloaddition of 2-Indolylmethanols with In Situ-Generated ortho-Naphthoquinone Methides

Lai,

Qu,

Yin

et al. 2024

J. Org. Chem.

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A cooperative catalysis-enabled (4 + 3) cycloaddition of 2-indolylmethanols with ortho-naphthoquinone methides (o-NQMs), which were in situ-generated from enynones, has been established in the presence of silver/Brønsted acid cocatalysts. In the reaction pathway, the key o-NQM intermediates were formed through Ag(I)-catalyzed cyclization of enynones, while the indole-based carbocation intermediates were generated via Brønsted acid-catalyzed dehydration of 2-indolylmethanols. By this approach, a wide range of seven-membered cyclohepta[b]indoles were synthesized in good yields with high efficiency under mild reaction conditions, which serves as a useful strategy toward constructing indole-fused seven-membered rings. Moreover, the catalytic asymmetric version of this (4 + 3) cycloaddition has been realized under the cooperative catalysis of Ag(I) with chiral phosphoric acid, which offered chiral cyclohepta[b]indole with a good enantioselectivity (75% ee). This work not only represents the first cooperative catalysis-enabled (4 + 3) cycloaddition of 2-indolylmethanols but also provides a good example for o-NQM-involved cycloadditions, which will contribute to the chemistry of 2-indolylmethanols and enrich the research contents of cooperative catalysis.

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“…Thiazoloindoles, [1] such as isothiazolo[5,4‐ b ]indole alkaloids brassilexin and sinalexin, [2] thiazolo[3,2‐ a ]indole alkaloid brassicanal B, [3] thiazolo[3,4‐ a ]indoles, [4] thiazolo[5,4‐ e ]indoles, [5] thiazolo[5,4‐ b ]indoles, [6] and thiazolo[4,5‐ b ]indoles, [7] are important thiazole‐fused indole derivatives present in a large number of naturally occurring and artificial heterocycles with significant biological activities (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Concise Synthesis of Thiazolo[4,5‐b]indoles via Ring Switch/Cyclization Sequences

Yamada,

Tsubogo,

Kanazawa

et al. 2023

Eur J Org Chem

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The unexpected reactions of indoline hemiaminals affords 2,5‐diaryl‐4‐hydroxythiazolines through a thioamidation/ring switch sequence. The key to success of this transformation is to use a thioamide as a thiazoline precursor under transient tautomeric control. This transformation features mild reaction conditions and good yields with broad functional group tolerance (17 examples, up to 99 % yield). Further transformations of the thiazolines provide a direct entry to dihydrothiazolo[4,5‐b]indoles and thiazolo[4,5‐b]indoles.

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Brønsted Acid Catalyzed (3+2)‐Cycloaddition of Thioketones and Indole‐2‐Carbinols Toward Thiazolo[3,4‐a]indoles

Cited by 9 publications

References 49 publications

Synthesis, Antimicrobial Activity and Molecular Docking of Some Novel 2-Aryl-4H-[1,3]-thiazolo[4,5-b]indoles

Synthesis, Antimicrobial Activity and Molecular Docking of Some Novel 2-Aryl-4H-[1,3]-thiazolo[4,5-b]indoles

Cooperative Catalysis-Enabled (4 + 3) Cycloaddition of 2-Indolylmethanols with In Situ-Generated ortho-Naphthoquinone Methides

Concise Synthesis of Thiazolo[4,5‐b]indoles via Ring Switch/Cyclization Sequences

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