50602-41-0Relevant articles and documents
Thiols Act as Methyl Traps in the Biocatalytic Demethylation of Guaiacol Derivatives
Grimm, Christopher,Kroutil, Wolfgang,Pompei, Simona,Schiller, Christine,Schober, Lukas
supporting information, p. 16906 - 16910 (2021/07/02)
Demethylating methyl phenyl ethers is challenging, especially when the products are catechol derivatives prone to follow-up reactions. For biocatalytic demethylation, monooxygenases have previously been described requiring molecular oxygen which may cause oxidative side reactions. Here we show that such compounds can be demethylated anaerobically by using cobalamin-dependent methyltransferases exploiting thiols like ethyl 3-mercaptopropionate as a methyl trap. Using just two equivalents of this reagent, a broad spectrum of substituted guaiacol derivatives were demethylated, with conversions mostly above 90 %. This strategy was used to prepare the highly valuable antioxidant hydroxytyrosol on a one-gram scale in 97 % isolated yield.
Regioselectivity of Cobalamin-Dependent Methyltransferase Can Be Tuned by Reaction Conditions and Substrate
Pompei, Simona,Grimm, Christopher,Farnberger, Judith E.,Schober, Lukas,Kroutil, Wolfgang
, p. 5977 - 5983 (2020/10/06)
Regioselective reactions represent a significant challenge for organic chemistry. Here the regioselective methylation of a single hydroxy group of 4-substituted catechols was investigated employing the cobalamin-dependent methyltransferase from Desulfitobacterium hafniense. Catechols substituted in position four were methylated either in meta- or para-position to the substituent depending whether the substituent was polar or apolar. While the biocatalytic cobalamin dependent methylation was meta-selective with 4-substituted catechols bearing hydrophilic groups, it was para-selective for hydrophobic substituents. Furthermore, the presence of water miscible co-solvents had a clear improving influence, whereby THF turned out to enable the formation of a single regioisomer in selected cases. Finally, it was found that also the pH led to an enhancement of regioselectivity for the cases investigated.
Functional Group Interconversion of Alkylidenemalononitriles to Primary Alcohols by a Cooperative Redox Operation
Emmetiere, Fabien,Grenning, Alexander J.
, p. 3077 - 3085 (2020/08/10)
Functional group interconversions are essential chemical processes enabling synthesis. In this report, we describe a strategy to convert alkylidenemalononitriles into primary alcohols in one step. The reaction relies on a choreographed redox process invol
Synthesis and anti-inflammatory activity of isoquebecol
Cardinal, Sébastien,Paquet-C?té, Pierre-Alexandre,Azelmat, Jabrane,Bouchard, Corinne,Grenier, Daniel,Voyer, Normand
, p. 2043 - 2056 (2017/03/23)
We report here the synthesis of isoquebecol, an unprecedented constitutional isomer of quebecol, a polyphenolic compound discovered in maple syrup. The methodology used to prepare isoquebecol involves, as key steps, the formation of a dibromoalkene from an α-ketoester precursor, followed by a double Suzuki-Miyaura reaction. The anti-inflammatory activity of isoquebecol was studied on macrophage cells by monitoring its ability to inhibit LPS-induced IL-6 secretion. Results show that this new compound has an improved bioactivity over that of its natural isomer. Precursors and derivatives of quebecol, isoquebecol and model analog 2,3,3-triphenylpropanol were also prepared and tested in this study. Comparison between the three series of compounds led to establishing new SARs concerning the aryl ring substitution pattern on the triarylpropanol scaffold and substructure functionalization.
Syntheses of retipolide E and ornatipolide, 14-membered biaryl-ether macrolactones from mushrooms
Ingerl, Andrea,Justus, Karl,Hellwig, Veronika,Steglich, Wolfgang
, p. 6548 - 6557 (2008/02/03)
Two approaches for the total synthesis of the spiromacrolide retipolide E (5) are described, the first using a modified Mitsunobu reaction as key step for the formation of the strained 14-membered macrolactone, the second a nucleophilic aromatic substitution (SNAr). In the first approach an α-oxomacrolactone 15 was obtained, which could either be converted into ornatipolide (6) or further transformed into racemic retipolide E [(R,S)-5] by directed aldol condensation with a methyl arylpyruvate. The second approach allowed the synthesis of either racemic or enantiomerically pure retipolide E (5). In the latter case Evans' methodology was used for the introduction of stereogenic center via stereoselective alkylation. The oxazolidinone auxiliary was removed under mild conditions by exchange for 2-arylethanol 22 with Otera's distannoxane catalyst. Synthetic retipolide E allowed the identification of this biosynthetic intermediate in the fruit bodies of the North American mushroom Retiboletus retipes.
NOVEL BICYCLIC AND TRICYCLIC PYRROLIDINE DERIVATIVES AS GNRH ANTAGONISTS
-
, (2008/06/13)
Bicyclic and tricyclic pyrrolidine derivatives are disclosed that are useful as antagonists of the GnRH receptor. Methods for using the novel compounds to treat GnRH-related disorders are also provided, as are pharmaceutical compositions and novel synthetic methods.
Phenol nitration from a 2-(nitrooxy)ethyl side chain
Castedo,Borges,Marcos,Tojo
, p. 1717 - 1727 (2007/10/02)
A novel nitration of phenols is described on 2-(3-hydroxy-4-methoxyphenyl)ethyl nitrate (2), which is synthesized by three alternative routes.
HYDROXYCINNAMIC ACID ESTERS OF PHENETHYLALCOHOL GLYCOSIDES FROM REHMANNIA GLUTINOSA VAR. PURPUREA
Sasaki, Hiroshi,Nishimura, Hiroaki,Chin (Chen Zhengxiong), Masao,Mitsuhashi, Hiroshi
, p. 875 - 880 (2007/10/02)
Five new hydroxycinnamic acid esters of phenethylalcohol glycosides named jionosides C, D, E, A2 and B2, together with nine known compounds, have been isolated from roots of Rehmannia glutinosa var. purpurea and their structures elucidated on the basis of chemical and spectral evidences. Key Word Index-Rehmannia glutinosa var. purpurea; Scrophulariaceae; phenethylalcohol glycosides; jionosides.
