A Synthetic Route to Chiral Dihydrobenzothiazines through Ring Opening of Activated Aziridines with 2‐Halothiophenols/Copper‐Powder‐Mediated C−N Cyclization

Ghorai, Manas K.; Sayyad, Masthanvali; Nanaji, Yerramsetti; Jana, Sourita

doi:10.1002/asia.201500153

Cited by 25 publications

(5 citation statements)

References 102 publications

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“…The authors proposed a Lewis acid-catalyzed S N 2-type ring-opening with thiophenol as proposed in an earlier study published same year. 52 The ring-opening product 69 undergoes C-N cyclization under influence of copper powder to give product 70. The Cu(I)-mediated generation of radical cation 71 from product 70, followed by its desulfonylation gives a cationic intermediate 72 which undergoes aromatization to give the final product.…”

Section: Scheme 21mentioning

confidence: 99%

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

Singh¹,

Sudheesh²,

Keroletswe³

2017

Arkivoc

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The inherent reactivity of the aziridine ring due to ring-strain makes it valuable building blocks for the synthesis of other heterocyclic motifs of biological relevance. Of particular significance is the generation of azomethine ylides from them and cycloaddition of ylides with alkenes, alkynes, and heterocumulenes. The ring undergoes opening followed by cyclization with a variety of reagents either in the presence of a catalyst or without any catalyst. This review article discusses the recent applications of aziridines in syntheses of four-to seven-membered heterocycles of biological relevance such as azetidines, 2

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Section: Scheme 21mentioning

confidence: 99%

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

Singh¹,

Sudheesh²,

Keroletswe³

2017

Arkivoc

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“…Ghorai et al developed a strategy for forming dihydrobenzothiazines through ring-opening of aziridines with 2-halothiophenols. [28] Liu et al demonstrated the synthesis of dihydrobenzothiazines from alkenes with sulfonamides and N-sulfanylsuccinimides. [29] Taking cues from the reliable methods for the synthesis of 1,4-oxathiin [19c] and 2,3-dihydrobenzothiazine, [28] we have chosen the reaction conditions for the ring-closing reaction of βhydroxysulfides and β-aminosulfides as shown in Scheme 3.…”

Section: Resultsmentioning

confidence: 99%

“…Taking cues from the reliable methods for the synthesis of 1,4‐oxathiin [19c] and 2,3‐dihydrobenzothiazine, [28] we have chosen the reaction conditions for the ring‐closing reaction of β‐hydroxysulfides and β‐aminosulfides as shown in Scheme 3.…”

Section: Resultsmentioning

confidence: 99%

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Regioselective Ring‐Opening of Epoxide and N‐Tosylaziridine with 4‐Hydroxydithiocoumarin: Key Precursors for 2,3‐Dihydro‐1,4‐oxathiin and 2,3‐Dihydro‐1,4‐thiazine Derivatives

et al. 2022

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Regioselective ring‐opening reaction between 4‐hydroxydithiocoumarins with various epoxides and N‐tosylaziridines is achieved for the synthesis of β‐hydroxysulfides and β‐N‐tosylaminosulfides. The present protocols showed high regioselectivity, broad substrates scope compatibility, and mild reaction conditions. In addition, some of the ring‐opening products are utilized for the conversion of 2,3‐dihydro‐1,4‐oxathiin and 2,3‐dihydro‐1,4‐thiazine derivatives in presence of 10 mol% CuI in DMF at 120°C. Moreover, the antiproliferative activity study of the newly synthesized compounds, namely β‐hydroxysulfides (3 d, 3 i & 3 m) and β‐aminosulfides (5 a & 5 e), have been investigated. Furthermore, flow cytometry analysis‐based measurements of elevated reactive oxygen species (ROS) upon treatment of MCF‐7 and HeLa cells with 3 d, 3 i, and 3 m are commensurate with their anti‐cancer properties.

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“…The mechanism of the reaction possibly follows the copper-powder-mediated C-N cyclization as described in Ghorai's earlier report, 16 with the final aromatization step involving Cu(I)-mediated desulfonylation via the formation of cationic thioether intermediate XIV (Scheme 18).…”

Section: Scheme 17 Synthesis Of 2-alkylindolesmentioning

confidence: 90%

Recent Advances in the Regioselective Synthesis of Indoles via C–H Activation/Functionalization

Kumar

Sharma

2018

Synthesis

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Indole is an important heterocyclic motif that occurs ubiquitously in bioactive natural products and pharmaceuticals. Immense efforts have been devoted to the synthesis of indoles starting from the Fisher indole synthesis to the recently developed C–H activation/functionalization-based methods. Herein, we have reviewed the progress made on the regioselective synthesis of functionalized indoles, including 2-substituted, 3-substituted and 2,3-disusbstituted indoles, since the year 2010.1 Introduction2 Metal-Catalyzed Synthesis of 2-Substituted Indoles3 Metal-Catalyzed Synthesis of 3-Substituted Indoles4 Metal-Free Synthesis of 3-Substituted Indoles5 Metal-Catalyzed 2,3-Disubstituted Indole Synthesis5.1 Metal-Catalyzed Intramolecular 2,3-Disubstituted Indole Synthesis5.2 Metal-Catalyzed Intermolecular 2,3-Disubstituted Indole Synthesis6 Metal-Free 2,3-Disubstituted Indole Synthesis6.1 N-Protected 2,3-Disubstituted Indole Synthesis6.2 N-Unprotected 2,3-Disubstituted Indole Synthesis7 Applications8 Summary and Outlook

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A Synthetic Route to Chiral Dihydrobenzothiazines through Ring Opening of Activated Aziridines with 2‐Halothiophenols/Copper‐Powder‐Mediated C−N Cyclization

Cited by 25 publications

References 102 publications

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

Recent applications of aziridine ring expansion reactions in heterocyclic synthesis

Regioselective Ring‐Opening of Epoxide and N‐Tosylaziridine with 4‐Hydroxydithiocoumarin: Key Precursors for 2,3‐Dihydro‐1,4‐oxathiin and 2,3‐Dihydro‐1,4‐thiazine Derivatives

Recent Advances in the Regioselective Synthesis of Indoles via C–H Activation/Functionalization

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