Oxidized Welwitindolinones from Terrestrial <i>Fischerella </i>spp.

Jiménez, Jorge I.; Huber, Udo; Moore, Richard E.; Patterson, Gregory M. L.

doi:10.1021/np980485t

Cited by 178 publications

(64 citation statements)

References 17 publications

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“…Fischerellin A also exhibit fungicidal and herbicidal properties and is a potent photosystem-II inhibitor. Curiously, the chemical study of the terrestrial strains of F. muscicola yielded totally different compounds of indole nature, fischerindoles and welwintindolinones among others (Park et al 1992;Jimenez et al 1999) (Fig. 8), that illustrates the importance of the environment (aquatic, terrestrial) in the development of differentiated chemical interactions with the ecosystem.…”

Section: Other Miscellaneous Compoundsmentioning

confidence: 99%

Allelopathic agents from aquatic ecosystems: potential biopesticides models

et al. 2007

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Allelopathy is usually regarded as a terrestrial science and little attention has been paid to the allelochemicals involved in the interactions between aquatic autotrophs. Also, chemicals involved in the interaction between algae (macro or microscopic) and their environment are not often acknowledged as allelopathic. Allelopathy is a key factor for explaining microalgae assemblages, community structure and the dynamics of the populations within the ecosystem. Herein we present an overview of what is known in this field, describing the chemicals yet identified and which kind of interactions are they involved in.

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Section: Other Miscellaneous Compoundsmentioning

confidence: 99%

Allelopathic agents from aquatic ecosystems: potential biopesticides models

et al. 2007

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“…[9] The enamine-mediated aldol reactions of isatins and ketones or enolizable aldehydes have been used in recent years for the synthesis of 3-alkyl-3-hydroxyindolin-2-ones, [10] which are important biologically active natural products and medicinal compounds. [11] Since isatin contains an activated ketone group, we tested our hypothesis with isatin (10 a) and acetone (11 a) as the model substrates, and some tertiary amines (1)(2)(3)(4)(5)(6)(7)(8) as the catalysts (Scheme 2). The results of the catalyst screening and optimizations are presented in Table 1.…”

mentioning

confidence: 99%

Quinidine Thiourea‐Catalyzed Aldol Reaction of Unactivated Ketones: Highly Enantioselective Synthesis of 3‐Alkyl‐3‐hydroxyindolin‐2‐ones

2010

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“…For example, the convolutamydines, 2 and the 3-hydroxywelwitindolinones are part of a growing list of biologically active 3-hydroxyoxindoles ( Figure 1). 3 3-Hydroxyoxindoles with a quaternary benzylic centre are a useful class of compounds also found in several drug candidates, including the potent, orally active growth hormone secretagogue SM-130686, 4 a drug that currently is under investigation for the treatment of growth hormone deficiency and other medical conditions (Figure 1). 5 There are a number of reports on the enantioselective formation of quaternary carbon centers at the 3-position of oxindoles.…”

Section: Graphical Abstractmentioning

confidence: 99%

A catalytic, mild and efficient protocol for the C-3 aerial hydroxylation of oxindoles

Buckley

D.‐R.

2013

Tetrahedron Letters

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A catalytic, mild and efficient protocol for the C-3 aerial hydroxylation of oxindoles his item ws sumitted to voughorough niversity9s snstitutionl epository y theGn uthorF Citation: fguviD fFF nd pix ¡ exhi hFEFD fFD PHIQF e tlytiD mild nd effiient protool for the gEQ eril hydroxyltion of oxindolesF etrE hedron vettersD SR @VAD ppFVRQEVRTF Additional Information:• xysgiX this is the uthor9s version of work tht ws epted for pulition in etrhedron vettersF ghnges resulting from the pulishE ing proessD suh s peer reviewD editingD orretionsD struturl formtE tingD nd other qulity ontrol mehnisms my not e refleted in this doumentF ghnges my hve een mde to this work sine it ws suE mitted for pulitionF e definitive version ws susequently pulished tX httpXGGdxFdoiForgGIHFIHITGjFtetletFPHIPFIIFHVQ Methods for functionalization of the oxindole nucleus are of significant value in medicinal chemistry and natural product synthesis.1 Due to their unprecedented structural diversity, biological activity and structural challenge, oxindoles continue to attract the interest of chemists and biologists alike. For example, the convolutamydines, 2 and the 3-hydroxywelwitindolinones are part of a growing list of biologically active 3-hydroxyoxindoles (Figure 1).3 3-Hydroxyoxindoles with a quaternary benzylic centre are a useful class of compounds also found in several drug candidates, including the potent, orally active growth hormone There are a number of reports on the enantioselective formation of quaternary carbon centers at the 3-position of oxindoles.6 For example, Hartwig first reported the palladiumcatalysed synthesis of oxindoles by amide α-arylation with ees of up to 67%; 7 This was later improved upon by Kündig using modified N-heterocyclic carbenes 8 and Marsden has reported several methods for the synthesis of 3-hydroxy-and 3-aminooxindoles. 9Copper-mediated processes have also recently been employed to prepare quaternary C-3 oxindoles by both the Kündig 10 and Taylor groups.11 Also of note are the recent reports by Franz,12 who has reported the asymmetric direct addition of nucleophiles to isatins using chiral Lewis acids, and Shibata and Toru who have reported the asymmetric C-3 hydroxylation of oxindoles also using chiral Lewis acids, with an oxaziridine as the stoicheiometric oxidant. 13 Thus owing to the significance of the oxindole structural motif, the development of catalytic methods for the synthesis of oxindoles bearing a C-3 hydroxy quaternary centre is highly desirable.Gassman and Halweg reported the air oxidation of oxindoles to isatins (Scheme 1) through treatment of 3-methylthiooxindoles with a strong stoicheiometric base and air; strict anhydrous conditions were required in order to prevent degradation of the isatin to the corresponding anthranilic acid.14 We also noted the recent report from Curran and co-workers, 15 where the attempted removal of the trimethylsilyl (TMS) group from 1 resulted in 3-hydroxy-1,3-dihydroindol-2-one 2 being the sole product of the reaction (Scheme 2). Careful investigation of...

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Oxidized Welwitindolinones from Terrestrial Fischerella spp.

Cited by 178 publications

References 17 publications

Allelopathic agents from aquatic ecosystems: potential biopesticides models

Allelopathic agents from aquatic ecosystems: potential biopesticides models

Quinidine Thiourea‐Catalyzed Aldol Reaction of Unactivated Ketones: Highly Enantioselective Synthesis of 3‐Alkyl‐3‐hydroxyindolin‐2‐ones

A catalytic, mild and efficient protocol for the C-3 aerial hydroxylation of oxindoles

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