Total Synthesis of (±)-2-Pupukeanone

and, Nein-Chen Chang; Chang, C.P.

doi:10.1021/jo9603338

Cited by 31 publications

(9 citation statements)

References 17 publications

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“…Regulatory subunits in yeast have not yet been identified, but are anticipated. Mg2+ or Mn2+ in the rat kidney and human erythrocyte enzymes (Lebo and Kredich, 1978;Beamer et al, 1980;Chang, 1996). In the absence of thiols, approximately 70% of native rat kidney y-GCS migrates on sodium dodecry1 sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with an apparent M, of approximately 100,000 indicating that the subunits are linked by at least one disulfide bond in most of the enzyme (Huang et al, 1993).…”

Section: I11 Y-glutamylcysteine Synthetasementioning

confidence: 99%

“…Thus, Chang (1996) reports that trinitrobenzene sulfonate (TNBS) inactivates rat kidney y-GCS and that the rate of inactivation is increased by Mg2+ and related metal ions. Although several amino groups are presumably modified by TNBS, Lys-38 is the only amino group modified more rapidly in the presence of Mg2+.…”

Section: Chemical Mechanismmentioning

confidence: 99%

“…Site-directed mutagenesis studies show that alteration of Lys-38 to Arg has little effect on activity, but replacement with Asn or Glu increases KG,'" by two-to threefold and decreases specific activity by approximately 50%. From these modest changes, Chang (1996) concludes that Lys-38 is in the glutamate binding site, perhaps contributing to binding of the carboxylate anion. Also investigating the role of basic residues, Tnoue et a].…”

Section: Chemical Mechanismmentioning

confidence: 99%

See 2 more Smart Citations

The Enzymes of Glutathione Synthesis: γ‐Glutamylcysteine Synthetase

Griffith

Mulcahy

1999

Advances in Enzymology - And Related Areas of Molecular Biology

179

170

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Section: I11 Y-glutamylcysteine Synthetasementioning

confidence: 99%

Section: Chemical Mechanismmentioning

confidence: 99%

Section: Chemical Mechanismmentioning

confidence: 99%

See 1 more Smart Citation

The Enzymes of Glutathione Synthesis: γ‐Glutamylcysteine Synthetase

Griffith

Mulcahy

1999

Advances in Enzymology - And Related Areas of Molecular Biology

179

170

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“…Compound 1 also possessed an unprecedented tricyclic-6/5/5-[4.3.1.0 1,6 ]decane skeleton, especially with a C2-C10-C7 bridge across two carbon rings. The ring system of 1 was similar to that of the pupukeanan skeleton (tricyclic-6/5/6-[4.3.1.0 3,7 ]decane) with its carbon bridge located in the contiguous carbon of the cyclohexanone residue in 1, which also suggested that they should be biosynthesized with similar pathways [27][28][29][30]. To our best knowledge, the carbon skeleton of novel 1 was first reported in the norsesquiterpene series and could be named as norpupukeanane skeleton.…”

Section: Structural Elucidationmentioning

confidence: 77%

Sesquiterpenes and Cyclodepsipeptides from Marine-Derived Fungus Trichoderma longibrachiatum and Their Antagonistic Activities against Soil-Borne Pathogens

Xiao

et al. 2020

Marine Drugs

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Soil-borne pathogens, including phytopathogenic fungi and root-knot nematodes, could synergistically invade vegetable roots and result in serious economic losses. The genus of Trichoderma has been proven to be a promising reservoir of biocontrol agents in agriculture. In this study, the search for antagonistic metabolites from a marine-derived fungus, Trichoderma longibrachiatum, obtained two structural series of sesquiterpenes 1–6 and cyclodepsipeptides 7–9. Notably, the novel 1 was a rare norsesquiterpene characterized by an unprecedented tricyclic-6/5/5-[4.3.1.01,6]-decane skeleton. Their structures were elucidated by extensive spectroscopic analyses, while the absolute configuration of novel 1 was determined by the comparison of experimental and calculated ECD spectra. The novel 1 and known 2 and 3 showed significant antifungal activities against Colletotrichum lagrnarium with MIC values of 8, 16, and 16 μg/mL respectively, even better than those of the commonly used synthetic fungicide carbendazim with 32 μg/mL. They also exhibited antifungal potential against carbendazim-resistant Botrytis cinerea. Cyclodepsipeptides 7–9 showed moderate nematicidal activities against the southern root-knot nematode (Meloidogyne incognita). This study constitutes the first report on the antagonistic effects of metabolites from T. Longibrachiatum against soil-borne pathogens, also highlighting the integrated antagonistic potential of marine-derived T. Longibrachiatum as a biocontrol agent.

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“…Construction of Isotwistane and Homoisotwistane Skeletons Isotwistane is an all-carbon tricyclic compound, and its structural motif is found in natural products such as pupukeananes, [8][9][10][11][12] palhinines, [13][14][15] and seychellene. [16][17][18] These types of compounds with (homo) isotwistane skeleton were attracted by their potential for perfumery, and the difference of scent derived from their chirality could be an important research target.…”

Section: Resultsmentioning

confidence: 99%

Construction of Optically Active Isotwistanes and Aminocyclitols Using Chiral Cyclohexadiene as a Common Intermediate

Harada

Kino

et al. 2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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We have developed a new method for synthesizing chiral isotwistane and homoisotwistane skeletons as well as aminocyclitols in a highly stereoselective manner. These results were achieved through the use of a common intermediate, which was derived from the ytterbium-catalyzed asymmetric Diels-Alder reaction of Danishefsky diene.Key words isotwistane; homoisotwistane; aminocyclitol; Diels-Alder; asymmetric catalysis; hetero-DielsAlder Many biologically active compounds possess a cyclic skeleton with center chirality in their structure. Therefore, the stereoselective synthesis of optically active carbon frameworks is in high demand for synthetic and medicinal chemists. The Diels-Alder reaction has been widely used for this purpose to construct six-membered carbocycles, and the catalytic and enantioselective variant of this reaction has been studied for decades. 1) Our group reported the first example of the catalytic and asymmetric Diels-Alder reaction of Danishefsky diene (1) 2,3) (Chart 1). Functionalized cyclohexene 3 was obtained in optically pure form, and 3 could be transformed to cyclohexenone 4 in quantitative yield. Both functionalized compounds could be potential synthetic intermediates, and we have previously demonstrated the synthetic utility of this reaction. 4-7)In the present study, silyloxy-substituted cyclohexadiene 7 derived from 4 was shown to be a key intermediate for two types of synthetically useful chiral building blocks, i.e., the tricyclo[4.3.1.0 3,7 ] decane (isotwistane 8, n=1) and tricyclo[5.3.1.0 3,8 ] undecane (homoisotwistane 8, n=2) skeletons via the intramolecular Diels-Alder reaction, and aminocyclitol 10 via the intermolecular hetero-Diels-Alder reaction with nitrosobenzene (Chart 2). Results and DiscussionConstruction of Isotwistane and Homoisotwistane Skeletons Isotwistane is an all-carbon tricyclic compound, and its structural motif is found in natural products such as pupukeananes, [8][9][10][11][12] palhinines, [13][14][15] and seychellene. [16][17][18] These types of compounds with (homo) isotwistane skeleton were attracted by their potential for perfumery, and the difference of scent derived from their chirality could be an important research target. Due to the unique structure of isotwistanes, the total syntheses of biologically active compounds with isotwistane skeletons have been studied by many research groups. [19][20][21][22][23] Most of these studies have used the intramolecular DielsAlder reaction to build the fused structure of isotwistane. Based on these previous studies, we planned the synthesis of a chiral isotwistane skeleton by two Diels-Alder reactions: our asymmetric Diels-Alder reaction and a sequential intramolecular Diels-Alder reaction.Dienophiles 2a-d with an olefin in the side chain (R) were prepared. We expected that Lewis acidic activation of the dienophile would occur site-specifically only at the acyloxazolidinone moiety, and the Diels-Alder reaction would take place at the adjacent olefin. With the application of our ytterbium catalyst, 3) the asy...

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Total Synthesis of (±)-2-Pupukeanone

Cited by 31 publications

References 17 publications

The Enzymes of Glutathione Synthesis: γ‐Glutamylcysteine Synthetase

The Enzymes of Glutathione Synthesis: γ‐Glutamylcysteine Synthetase

Sesquiterpenes and Cyclodepsipeptides from Marine-Derived Fungus Trichoderma longibrachiatum and Their Antagonistic Activities against Soil-Borne Pathogens

Construction of Optically Active Isotwistanes and Aminocyclitols Using Chiral Cyclohexadiene as a Common Intermediate

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