Inhibition of NF-Kappa B Activation by Penicillic Acid and Dihydropenicillic Acid Isolated from Fungi

Umezawa, Kazuo; Tachibana, Miyuki; Matsui, Chino; Takeuchi, Yoshinori; Suzuki, Eriko

doi:10.3987/com-08-s(n)120

Cited by 13 publications

(1 citation statement)

References 10 publications

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“…The (E)-β-methoxyacrylate subunit is found in various biologically active natural products such as dihydrokawain, 1 tetronic acids, 2 five-and six-membered lactones, [3][4][5][6][7][8][9][10] and β-methoxyacrylate antibiotics, [11][12][13][14] including melithiazol 12 and haliangicin 14 (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Alkoxide-catalyzed addition of alkyl carbonates across alkynes – stereoselective synthesis of (E)-β-alkoxyacrylates

et al. 2017

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Section: Introductionmentioning

confidence: 99%

Alkoxide-catalyzed addition of alkyl carbonates across alkynes – stereoselective synthesis of (E)-β-alkoxyacrylates

et al. 2017

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Intermolecular Methoxycarbonylation of Terminal Alkynes Catalyzed by Palladium(II) Bis(oxazoline) Complexes

et al. 2009

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The b-methoxyacrylate system is a common structure present in biologically active natural products such as dihydrokawain [1a] (and related six-membered lactones [1b-e] ), tetronic acids [2a] (and related five-membered lactones [2b-e] ), and bmethoxyacrylate antibiotics. [3] Transition-metal-catalyzed reactions of unsaturated systems has recently been widely used for the construction of a variety of carbo-and heterocycles.[4] Palladium-catalyzed carbonylation of alkynes has provided several kinds of transformation. [5] In general, the intermolecular addition of alcohols to alkynes is more difficult to accomplish than the intramolecular process, thus requiring a stronger p Lewis acid catalyst.[6] Although many examples of the intramolecular oxycarbonylation of 4-alkynols, [7] 4-alkynones, [8] and propargyl acetates [9] have been reported, the intermolecular reaction is extremely rare. Tamaru and co-workers reported the palladium-catalyzed carbonylation of 4-alkyl-or 4-aryl-3-butyn-1-ols, in which MeOH attacked the C4 position of the alkyne to afford methoxycarbonylated five-membered lactones (Scheme 1).[5a]The reaction of the terminal alkyne was not described.The intermolecular methoxycarbonylation of terminal alkynes is a synthetically valuable method for the direct conversion of terminal alkyne units into b-methoxyacrylate units. To our knowledge, there is no precedent for the intermolecular methoxycarbonylation of a simple terminal alkyne. Recently, we reported the ligand-controlled tandem carbonylative cyclization of propargyl acetates with 1,4-diyne [10a] and 1,5-diyne structures. [10b] In the absence of the bis(oxazoline) ligand (box), the second triple bond did not react. However, the use of the box ligand caused a significant change to the course of the reaction, and tandem carbonylative cyclization occurred as a result of insertion at the second triple bond. Although box ligands are among the most popular classes of chiral ligands in asymmetric chemistry, examples of the box ligand changing the course of the reaction are rare. [10,11] We believe that the box ligand enhances the p-electrophilicity of Pd II complexes, and thus promotes coordination of the second triple bond to Pd II , leading to the tandem reaction. We hypothesize that {(box)-Pd II } complexes should strongly activate the alkyne, so that the intermolecular methoxycarbonylation of alkynes can be realized. Consequently, we report the [(Phbox)Pd(tfa) 2 ]-catalyzed intermolecular methoxycarbonylation of alkyne 1 (Phbox = 2,2-isopropylidenebis(4-phenyl-2-oxazoline); tfa = trifluoroacetate; Table 1).Initially, the carbonylation of 1 a was performed under the conditions reported by Tamaru and co-workers. However, methoxyacrylate 2 a was not obtained, but instead the acetylene carboxylate [5b] (32 %) and maleate derivatives [5n] (20 %) were afforded, together with an unidentified mixture.[12] The reaction conditions were therefore changed to those used for our previously reported Pd II

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Intermolecular Methoxycarbonylation of Terminal Alkynes Catalyzed by Palladium(II) Bis(oxazoline) Complexes

Kato¹,

Motodate²,

Mochida³

et al. 2009

Angew Chem Int Ed

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Boxing clever: Direct conversion of a terminal alkyne group into a beta-methoxyacrylate is realized with the aid of the bis(oxazoline) ligand (box). Acetyl and ketal protecting groups, free hydroxy groups, and acid-sensitive glycosidic bonds are not affected under the reaction conditions. The one-pot synthesis of (+/-)-dihydrokawain from the homopropargyl alcohol is also achieved. tfa = trifluoroacetate.

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Inhibition of NF-Kappa B Activation by Penicillic Acid and Dihydropenicillic Acid Isolated from Fungi

Cited by 13 publications

References 10 publications

Alkoxide-catalyzed addition of alkyl carbonates across alkynes – stereoselective synthesis of (E)-β-alkoxyacrylates

Alkoxide-catalyzed addition of alkyl carbonates across alkynes – stereoselective synthesis of (E)-β-alkoxyacrylates

Intermolecular Methoxycarbonylation of Terminal Alkynes Catalyzed by Palladium(II) Bis(oxazoline) Complexes

Intermolecular Methoxycarbonylation of Terminal Alkynes Catalyzed by Palladium(II) Bis(oxazoline) Complexes

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