TFA-promoted direct C–H sulfenylation at the C2 position of non-protected indoles

Hostier, Thomas; Ferey, Vincent; Ricci, Gino; Pardo, Domingo Gomez; Cossy, Janine

doi:10.1039/c5cc05421d

Cited by 111 publications

(59 citation statements)

References 35 publications

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“…An unanticipated side reaction of DTNP with the INSL5 tryptophan was observed (SI, Figure S40). This modification has not been previously observed, although an analogous sulfenylation of indole at the C2‐position with N ‐(thio)succinimides as mediated by TFA has been reported . To circumvent this issue a two‐step synthetic strategy was adopted.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of the R27S Genetic Variant of Insulin‐like Peptide 5

et al. 2018

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We report the synthesis and in vitro bioactivity assessment for an insulin-like peptide 5 (INSL5) analogue that was recently discovered as a genetic mutation in an Amish population. The mutation was associated with improved metabolic status, and receptor-based antagonism was proposed as a potential mechanism for the altered phenotype. We determined the specific peptide analogue to be fully potent and of maximal efficacy at the human relaxin family peptide receptor 4 (RXFP4), suggesting an alternative basis for the observed effect. In preparation of this synthetically challenging hormone, we have introduced several improvements such as implementation of isoacyl chemistry for high-efficiency preparation of INSL5 B-chain and selective intramolecular A6-11 disulfide formation as a first step in sequential disulfide assembly.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of the R27S Genetic Variant of Insulin‐like Peptide 5

et al. 2018

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“…We started by studying the reaction of δ‐Toc‐SNPht with δ‐Toc under different conditions following literature reports. Actually, results obtained by using protic acids like TFA and MsOH, or Lewis acids like BF 3 OEt 2 , AlCl 3 , MgBr 2 , and CeCl 3 /NaI were frustrating, giving the expected sulfide ( δ , δ‐Toc ) 2 S in poor yields (5–20 %) and typically accompanied by variable amounts (3–10 %) of the corresponding symmetrical disulfide [( δ , δ‐Toc ) 2 S 2 vide infra)]. However, ortho ‐hydroxy‐ N ‐thiophthalimides can be used as sulfur transfer reagents also under mild basic conditions, through the formation of the corresponding transient electrophilic ortho ‐thioquinones .…”

Section: Resultsmentioning

confidence: 99%

Ditocopheryl Sulfides and Disulfides: Synthesis and Antioxidant Profile

Viglianisi

Vasa

Tanini

et al. 2019

Chemistry A European J

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Symmetrical ditocopheryl disulfides (Toc)2S2 and symmetrical and unsymmetrical ditocopheryl sulfides (Toc)2S were simply prepared under remarkably mild conditions with complete control of the regiochemistry by using δ‐, γ‐, and β‐tocopheryl‐N‐thiophthalimides (Toc‐NSPht) as common starting materials. The roles of sulfur atom(s), H‐bond and aryl ring substitution pattern on the antioxidant profile of these new compounds, which were assembled by linking together two tocopheryl units, are also discussed.

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“…), the product 2 a was obtained in 59% yield after 2 h, at room temperature (Table 1, entry 6). Control experiments indicated that the solvents directly influenced the yields of 2 a, whereas the best yield was obtained by using THF as the solvent (Table 1, entries [10][11][12][13][14][15][16][17][18][19]. ; however, the yields decreased with 1.0 equiv.…”

Section: Resultsmentioning

confidence: 99%

“…; however, the yields decreased with 1.0 equiv. [18] In addition, the use of diphenyl diselenide (1.5 equiv.) [16] Based on these results, we chose 1.1 equiv.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles

2019

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The intramolecular electrophilic cyclization of 3-organoselanyl-2-alkynylindoles providing the synthesis of 3-iodo-selenophene-fused indoles is reported herein. The strategy was extended to the preparation of 3-iodo-thiophene-fused indoles in a one-pot iodine-promoted thiolation of 2-alkynylindoles, followed by an electrophilic cyclization sequence. Besides, the synthesis of 3-butylselanyl-selenophene-fused indoles from 3butylselanyl-2-alkynylindoles was also developed using iron(III) chloride and dibutyl diselenide to promote the cyclization and functionalization of the heterocycle. The identification of the alkyl halide intermediate afforded evidence to the proposed mechanism, which indicated that the reactions proceed through the formation of an iodonium ion, followed by a selenium 5-endo-dig cyclization, to afford the indole derivatives. The 3-iodo-selenonophene-fused indoles prepared were applied as substrates in copper-catalyzed crosscoupling reactions with thiols to give the Ullmann type products in good yields. Scheme 2. General strategy for the preparation of 3-organoselanyl-2-alkynylindoles. Scheme 3. 3-Organoselanyl-2-alkynylindoles prepared.

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TFA-promoted direct C–H sulfenylation at the C2 position of non-protected indoles

Abstract: A simple, efficient and practical metal-free C-H sulfenylation process at the C2 position of non-protected indoles has been developed. 2-Thioindoles were obtained in moderate to high yields using stable and readily available N-(thio)succinimides at room temperature in the presence of TFA.

Cited by 111 publications

References 35 publications

Synthesis and Characterization of the R27S Genetic Variant of Insulin‐like Peptide 5

Synthesis and Characterization of the R27S Genetic Variant of Insulin‐like Peptide 5

Ditocopheryl Sulfides and Disulfides: Synthesis and Antioxidant Profile

Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles

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