A novel approach to bz-substituted tryptophans via Pd-catalysed coupling / annulation.

Jeschke, Torsten; Wensbo, David; Annby, Ulf; Gronowitz, Salo; Cohen, Louis A.

doi:10.1016/0040-4039(93)85073-6

Cited by 71 publications

(18 citation statements)

References 10 publications

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“…The known compounds ( Figure 2 ) were identified as dihydroconiferyl alcohol ( 2 ) [ 13 ], 1,3-dihydroxyl-5-propylbenzene ( 3 ) [ 14 ], 4-hydroxyacetophenone ( 4 ) [ 15 ], 3,4-dihydroxybenzaldehyde ( 5 ) [ 16 ], 2-ethyl-6-hydroxybenzoic acid ( 6 ) [ 17 ], 3,4-dihydroxyacetophenone ( 7 ) [ 18 ] and caffeic acid ( 8 ) [ 19 ] through a comparison with the NMR data in the literature.…”

Section: Resultsmentioning

confidence: 99%

Anticancer Phenolics from Dryopteris fragrans (L.) Schott

et al. 2018

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Cancer is one of the most major diseases that threatens human health and life. The aim of this work was to obtain novel anticancer molecules from D. fragrans, a kind of medicinal plant. The structure of the new compound was identified using spectroscopic data (1H-NMR, 13C-NMR and two dimensions NMR). Its anticancer properties were evaluated using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay against four human cells including lung cancer cells (A549), breast cancer cells (MCF-7), gastric cancer cells (SGC7901) and noncancerous human umbilical vein endothelial cells (HUVEC). A new phenylpropanoid—(E)-caffeic acid-9-O-β-d-xylpyranosyl-(1→2)-β-d-glucopyranosyl ester (1), with seven known compounds (2–8)—was isolated. The IC50 value of compound 1 against MCF-7 cells was 2.65 ± 0.14 µM, and the IC50 values of compound 8 against three cancer cells were below 20 µM.

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Section: Resultsmentioning

confidence: 99%

Anticancer Phenolics from Dryopteris fragrans (L.) Schott

et al. 2018

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“…The latter intramolecular Larock indole synthesis 232,233 utilized a 2-bromoaniline 234 and its reaction with an alkyne that incorporates a removable large terminal substituent (−SiEt 3 ) to sterically dictate the indole cyclization regioselectivity. 235,236 Importantly, the aniline acetamide not only served to deactivate the strained indole toward subsequent electrophilic reactions, but also favorably influenced the cyclization atropodiastereoselectivity. 237 They pursued two synthetic approaches, which are distinct in the order and timing of the key ring closures.…”

Section: Total Synthesis Of Chloropeptins and Complestatinsmentioning

confidence: 99%

Total Syntheses of Vancomycin-Related Glycopeptide Antibiotics and Key Analogues

2017

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A review of efforts that have provided total syntheses of vancomycin and related glycopeptide antibiotics, their agylcons, and key analogues is provided. It is a tribute to developments in organic chemistry and the field of organic synthesis that not only can molecules of this complexity be prepared today by total synthesis, but that such efforts can be extended to the preparation of previously inaccessible key analogues that contain deep-seated structural changes. With the increasing prevalence of acquired bacterial resistance to existing classes of antibiotics and with the emergence of vancomycin resistant pathogens (VRSA and VRE), the studies pave the way for the examination of synthetic analogues rationally designed to not only overcome vancomycin resistance, but to provide the foundation for the development of even more powerful and durable antibiotics.

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“…The use of further modified reaction conditions, enlisting a soluble tertiary amine base (vs NaHCO 3 ) avoided competitive de-chlorination and epimerization. The use of nonpolar aprotic solvents increased both the rate and conversions of the macrocyclization, permitting the use of lower reaction temperatures (110 °C), and the incorporation of a large removable terminal alkyne substituent (–SiEt3) as first disclosed by Larock 2,7 was used to control the indole cyclization regioselectivity. These studies represented the first reported examples of what we believe to be a powerful macrocyclization strategy rivaling the more conventional Stille 8 and Suzuki 9 cross-coupling reactions.…”

Section: Introductionmentioning

confidence: 99%

A Pd(0)-Mediated Indole (Macro)cyclization Reaction

2013

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Herein, we report a systematic study of the Larock indole annulation designed to explore the scope and define the generality of its use in macrocyclization reactions, its use in directly accessing the chloropeptin I versus II DEF ring system as well as key unnatural isomers, its utility for both peptide-derived and more conventional carbon-chain based macrocycles, and its extension to intramolecular cyclizations with formation of common ring sizes. The studies define a powerful method complementary to the Stille or Suzuki cross-coupling reactions for the synthesis of cyclic or macrocyclic ring systems containing an embedded indole, tolerating numerous functional groups and incorporating various (up to 28-membered) ring sizes. As a result of the efforts to expand the usefulness and scope of the reaction, we also disclose a catalytic variant of the reaction along with a powerful Pd2(dba)3 derived catalyst system, and an examination of the factors impacting reactivity and catalysis.

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A novel approach to bz-substituted tryptophans via Pd-catalysed coupling / annulation.

Cited by 71 publications

References 10 publications

Anticancer Phenolics from Dryopteris fragrans (L.) Schott

Anticancer Phenolics from Dryopteris fragrans (L.) Schott

Total Syntheses of Vancomycin-Related Glycopeptide Antibiotics and Key Analogues

A Pd(0)-Mediated Indole (Macro)cyclization Reaction

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