ChemInform Abstract: Synthesis and Cytotoxicity of Acetyl‐4H, 9H‐Naphto[2,3‐b]thiophene‐4,9‐diones.

Huang, Li‐Jiau; Kuo, Sheng‐Chu; Perng, C.‐Y.; Chao, Yu-Hua; Wu, Tong; McPhail, Andrew T.; Mauger, Anthony B.; Cheng, H.‐H.; Lee, K.‐H.

doi:10.1002/chin.199906105

Cited by 3 publications

(3 citation statements)

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“…Polycyclic thiophene and benzothiophene-based heterocycles are key intermediates and relevant targets in the fields of synthetic, medicinal, and materials chemistry. − In modern drug discovery, polysubstituted thiophenes are important because they constitute a bioisosteric replacement for the phenyl ring. Thiophene-containing derivatives are often characterized by reduced toxicity and better pharmacokinetic properties .…”

Section: Introductionmentioning

confidence: 99%

Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions

et al. 2020

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Scaffolds of thiophene and benzothiophene are the important class of bioactive compounds found abundant in nature. The Diels–Alder reactions of 2-(1′-cycloalkenyl)thiophenes and 2-(1′-cycloalkenyl)benzo[b]thiophenes having the alkene groups present in five-, six-, seven-, eight-, and twelve-membered rings with substituted N-phenylmaleimides are characterized. The size of the cycloalkene rings plays a critical role in dictating the product distributions of expected and isomerized Diels–Alder adducts. 2D NMR studies indicate that the isolated isomers for 2-(1′-cycloalkenyl)thiophenes having five-, six-, and seven-membered rings are aromatized benzothiophene products, whereas eight- and twelve-membered rings are un-rearranged adducts. In addition, the product of subsequent ene-reaction with the N-phenylmaleimide is isolated for the five- and six-membered ring cases. Interestingly, in the 2-(1′-cycloalkenyl)benzo[b]thiophene having five-, six-, seven-, eight-, and twelve-membered rings, the un-rearranged dibenzothiophene Diels–Alder adduct is isolated in every instance. Molecular mechanics and density functional theory (M06-2X and PBE0-D3) calculations are performed to understand the differential reactivity of the various dienes for both the initial Diels–Alder reaction and a possible, subsequent ene reaction.

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Section: Introductionmentioning

confidence: 99%

Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions

et al. 2020

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“…Naphtho[2,3- b ]thiophene-4,9-dione (NT) derivatives are investigated in medicinal chemistry as bioactive synthetic products possessing anticancer, − antiprotozoal, − and antipsoriatic properties. − In materials chemistry, NTs are promising precursors for the synthesis of electron-deficient compounds − and the preparation of building blocks for air-stable organic semiconductors. − …”

Section: Introductionmentioning

confidence: 99%

One-Pot Synthesis of 2-R-Naphtho[2,3-b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na₂S₂O₃

et al. 2021

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The concise and efficient one-pot synthesis of 2-Rnaphtho [2,3-b]thiophene-4,9-diones from 2-bromo-1,4-naphthoquinone and alkynes has been developed. The reaction proceeds through the formation of 2-(R-ethynyl)-1,4-naphthoquinones, which undergo transformation with Na 2 S 2 O 3 to 2-R-naphtho[2,3b]thiophene-4,9-diones via C−H sulfuration, accompanied by the formation of the aromatic Bunte salt, followed by its air oxidation and 5-endo-dig cyclization. The protocol is characterized by simplicity, good tolerance for functional groups, relatively mild conditions, and commercially available starting compounds.

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“…Thiophenes that are acylated at the 2- and 4-positions are especially important structural motifs in numerous bioactive molecules (Figure ). The traditional approach to obtaining 2-acylthiophenes relies on late-stage modification via the Friedel–Crafts acylation of thiophenes using specific Lewis acid promoters combined with acyl anhydrides or acid chlorides, which often provides poor atom economy and/or deleterious environmental effects . However, the synthesis of 2-acylthiophenes has received little attention and, to the best of our knowledge, there have been no reports to date concerning the straightforward synthesis of 2,4-diacylthiophenes from alkynes …”

Section: Introductionmentioning

confidence: 99%

One-Pot Synthesis of 2,4-Diacyl Thiophenes from α-Oxo Ketene Dithioacetals and Propargylic Alcohols

et al. 2020

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Although thiophenes having various functionalities are the basic structural units in numerous bioactive compounds and optoelectronic materials, synthetic routes to acylated thiophenes from aliphatic sulfur-containing starting materials are still rare. In particular, there have been no reports concerning the straightforward synthesis of 2,4-diacylthiophenes from alkynes. Herein, we describe a highly efficient and metal-free three-step one-pot synthetic approach to tetrasubstituted 2,4-diacylthiophenes from propargylic alcohols and α-oxo ketene dithioacetals. This research features a relay catalysis system that integrates Brønsted acid-catalyzed propargylation, molecular iodine-mediated electrophilic cyclization, and visible light-induced deiodinative oxygenation. The 2,4-diacylthiophenes serving as the key starting materials are readily synthesized, enabling facile construction of analogues of related biologically active compounds and the modular assembly of tetrasubstituted thienothiophenes.

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ChemInform Abstract: Synthesis and Cytotoxicity of Acetyl‐4H, 9H‐Naphto[2,3‐b]thiophene‐4,9‐diones.

Cited by 3 publications

References 1 publication

Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions

Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions

One-Pot Synthesis of 2-R-Naphtho[2,3-b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na₂S₂O₃

One-Pot Synthesis of 2,4-Diacyl Thiophenes from α-Oxo Ketene Dithioacetals and Propargylic Alcohols

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ChemInform Abstract: Synthesis and Cytotoxicity of Acetyl‐4H, 9H‐Naphto[2,3‐b]thiophene‐4,9‐diones.

Cited by 3 publications

References 1 publication

Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions

Diels–Alder/Ene Reactivities of 2-(1′-Cycloalkenyl)thiophenes and 2-(1′-Cycloalkenyl)benzo[b]thiophenes with N-Phenylmaleimides: Role of Cycloalkene Ring Size on Benzothiophene and Dibenzothiophene Product Distributions

One-Pot Synthesis of 2-R-Naphtho[2,3-b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na2S2O3

One-Pot Synthesis of 2,4-Diacyl Thiophenes from α-Oxo Ketene Dithioacetals and Propargylic Alcohols

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One-Pot Synthesis of 2-R-Naphtho[2,3-b]thiophene-4,9-diones via Cyclization of 2-(R-Ethynyl)-1,4-naphthoquinones with Na₂S₂O₃