7103-09-5Relevant articles and documents
Structure-activity relationship of the aromatic moiety of 6-substituted 5,6-dihydro-2H-pyran-2-one to find the novel compound showing higher plant growth inhibitory activity
Nishiwaki, Hisashi,Ochi, Ryota,Yamauchi, Satoshi,Yoneyama, Kaori
, p. 165 - 169 (2022/03/15)
In the course of our research on the structure-activity relationship of 5,6-dihydro-2H-pyran-2-one, (S)-6-[(R)-2-hydroxy-6-(4-fluorophenyl)hexyl]-5,6-dihydro-2H-pyran-2-one was found to show 2-3-fold more potent plant growth inhibitory activity against Italian ryegrass shoots (IC50 = 95 μm) and roots (IC50 = 17 μm) than compound bearing unsubstituted phenyl group. The small and electron withdrawing atom at 4-position of the benzene ring caused the higher activity.
Enantioselective Synthesis of Cyclic Nitrones by Chemoselective Intramolecular Allylic Alkylation of Oximes
Sandmeier, Tobias,Carreira, Erick M.
supporting information, p. 9913 - 9918 (2021/03/29)
The enantio- and chemoselective iridium-catalyzed N-allylation of oximes is described for the first time. Intramolecular kinetic resolution provides access to cyclic nitrones and enantioenriched aliphatic allylic alcohols. Salient features of this transformation are its ability to employ E/Z-isomeric mixtures of oxime starting materials convergently and high functional group tolerance. The implementation of N-allylation/1,3-dipolar cycloaddition reaction sequences furnishes tricyclic isoxazolidines in highly enantio- and diastereoselective fashion. The synthetic utility of the approach is demonstrated by the efficient, formal synthesis of the marine natural product (+)-halichlorine.
Iron-Catalyzed Cross-Coupling of Alkynyl and Styrenyl Chlorides with Alkyl Grignard Reagents in Batch and Flow
Deng, Yuchao,Wei, Xiao-Jing,Wang, Xiao,Sun, Yuhan,No?l, Timothy
supporting information, p. 14532 - 14535 (2019/11/21)
Transition-metal-catalyzed cross-coupling chemistry can be regarded as one of the most powerful protocols to construct carbon–carbon bonds. While the field is still dominated by palladium catalysis, there is an increasing interest to develop protocols that utilize cheaper and more sustainable metal sources. Herein, we report a selective, practical, and fast iron-based cross-coupling reaction that enables the formation of Csp?Csp3 and Csp2?Csp3 bonds. In a telescoped flow process, the reaction can be combined with the Grignard reagent synthesis. Moreover, flow allows the use of a supporting ligand to be avoided without eroding the reaction selectivity.
Visible-Light-Mediated Iminyl Radical Generation from Benzyl Oxime Ether: Synthesis of Pyrroline via Hydroimination Cyclization
Usami, Kaoru,Yamaguchi, Eiji,Tada, Norihiro,Itoh, Akichika
supporting information, p. 5714 - 5717 (2018/09/21)
The treatment of an O-(4-methoxybenzyl) oxime ether bearing an olefin substituent and 1-chloroanthraquinone (1-Cl-AQN) catalyst in 2-butanone under visible-light irradiation affords pyrroline via an iminyl radical intramolecular hydroimination. Mechanistic studies indicate that iminyl radical generation mainly proceeds by hydrogen abstraction of the photocatalyst from the benzyl position of the oxime. Moreover, the hydrogen atom was identified in circulation from the benzylic position of the substrates between AQN and 2-butanone to quench the carbon radical without requiring any additional reagents.
Synthesis and Neurotrophic Activity Studies of Illicium Sesquiterpene Natural Product Analogues
Richers, Johannes,P?thig, Alexander,Herdtweck, Eberhardt,Sippel, Claudia,Hausch, Felix,Tiefenbacher, Konrad
supporting information, p. 3178 - 3183 (2017/03/13)
Neurotrophic natural products hold potential as privileged structures for the development of therapeutic agents against neurodegeneration. However, only a few studies have been conducted to investigate a common pharmacophoric motif and structure–activity relationships (SARs). Here, an investigation of structurally more simple analogues of neurotrophic sesquiterpenes of the illicium family is presented. A concise synthetic route enables preparation of the carbon framework of (±)-Merrilactone A and (±)-Anislactone A/B on a gram scale. This has allowed access to a series of structural analogues by modification of the core structure, including variation of oxidation levels and alteration of functional groups. In total, 15 derivatives of the natural products have been synthesized and tested for their neurite outgrowth activities. Our studies indicate that the promising biological activity can be retained by structurally simpler natural product analogues, which are accessible by a straightforward synthetic route.
A Short Access to Symmetrically α,α-Disubstituted α-Amino Acids from Acyl Cyanohydrins
Boukattaya, Fatma,Caillé, Julien,Ammar, Houcine,Rouzier, Florian,Boeda, Fabien,Pearson-Long, Morwenna S. M.,Bertus, Philippe
, p. 906 - 916 (2016/03/12)
A straightforward synthesis of symmetrically α,α-disubstituted α-amino acids is presented. The key step of this process relies on the efficient double addition of Grignard reagents to acyl cyanohydrins to provide N-acyl amino alcohols selectively in good yields. The chemoselectivity of the reaction was modulated by the nature of the acyl moiety. Eleven amino acids were prepared, including the particularly simple divinylglycine, which is not easily accessible by using conventional methods.
Total synthesis of manzamine A and related alkaloids
Jakubec, Pavol,Hawkins, Alison,Felzmann, Wolfgang,Dixon, Darren J.
supporting information, p. 17482 - 17485 (2013/01/15)
Total syntheses of three structurally complex marine natural products, manzamine A, ircinol A, and ircinal A, are reported. The route pivoted on the construction of a late-stage protecting-group-free pentacyclic enol triflate coupling partner, from which all three family members were accessed divergently via palladium-catalyzed reactions. The rapid synthesis of this key pentacyclic enol triflate was achieved by a highly convergent union of five fragments through a stereoselective Michael addition, a three-component nitro-Mannich lactamization cascade, an unprecedented and highly stereoselective reductive nitro-Mannich cyclization cascade, a stereoselective organometallic addition, and a Z-selective alkene ring-closing metathesis. Altogether this chemistry has allowed the shortest synthetic route to date for manzamine A (18-step longest linear sequence) via a late-stage diversification point that is ideal for future manzamine A analogue synthesis.
Enantioselective copper-catalysed allylic alkylation of cinnamyl chlorides by Grignard reagents using chiral phosphine-phosphite ligands
Loelsberg, Wibke,Ye, Shute,Schmalz, Hans-Guenther
supporting information; experimental part, p. 2023 - 2031 (2010/10/21)
The copper(I)-catalysed SN2'-type allylic substitution of E-3-aryl-allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine-phosphite ligands a new copper(I)-based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio- and enantioselectivity. Best results were obtained using TADDOLderived ligands (3 mol%), copper(I) bromide?dimethyl sulfide (CuBr?SMe2) (2.5 mol%) and methyl tert-butyl ether (MTBE) as a solvent. Various (1- alkyl-allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho-substituted substrates). Both electron-rich and electron-deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr?SMe2 (2.5 mol%) in the presence of triphenyl phosphine (PPh3) (3 mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho-diphenylphosphanyl-arylphosphite ligand with an additional phenyl substituent in ortho'-position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl-, n-butyl-, isopropyl-, and 3-butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho'-position. The method was tested on a multimmol scale and is suited for application in natural product synthesis.
Au-catalyzed cyclization of monoallylic diols
Aponick, Aaron,Li, Chuan-Ying,Biannic, Berenger
, p. 669 - 671 (2008/09/17)
The Ph3PAuCl/AgOTf-catalyzed cyclization of monoallylic diols to form tetrahydropyrans is reported. The reactions proceed rapidly at temperatures as low as -78° C with catalyst loadings as low as 0.1 mol % to provide the products in 79-99% yield. A broad range of structurally diverse substrates perform well in the reaction. When 2,6-disubstituted tetrahydropyrans are produced, the reaction is highly diastereoselective for the 2,6-cis product.
Therapeutically Active Triazoles and Their Use
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Page/Page column 28, (2008/12/06)
Estratrien-triazoles corresponding to formula (I) (shown below) which are useful in therapy, especially for the treatment and/or prevention or inhibition of a steroid hormone dependent disorder, preferably a steroid hormone dependent disease or disorder requiring the inhibition of a 17β-hydroxysteroid dehydrogenase (17β-HSD) such as 17β-HSD type 1, type 2 or type 3 enzyme.
