- 2,2-Dimethyl-5-(5-R-2-furfurylidene)-1,3-dioxane-4,6-diones. 4. Synthesis, stereostructures, and properties of thiophene analogs
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The reaction of 2-formylthiophenes with Meldrum's acid gave the corresponding thenylidenedioxanediones, which, in contrast to the furfurylidene derivatives, have an s-trans conformation of the mutual orientation of the thiophene ring and the exocyclic double bond. Thenyldioxanediones were synthesized by the selective hydrogenation of the exocyclic double bond.
- Krapivin,Kul'nevich,Val'ter
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- Rhodium-catalyzed conjugate addition-enantioselective protonation: The synthesis of α,α′-dibenzyl esters
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α-Benzyl acrylates, which are conveniently prepared from the corresponding aldehydes, can be employed as substrates in a tandem rhodiumcatalyzed conjugate addition-enantioselective protonation protocol to afford enantiomerically enriched α,α′-dibenzyl est
- Frost, Christopher G.,Penrose, Stephen D.,Lambshead, Kim,Raithby, Paul R.,Warren, John E.,Gleave, Robert
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- Organocatalytic kinetic resolution of N-boc-isoxazolidine-5-ones
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Easily accessible racemic N-Boc-isoxazolidine-5-ones undergo enantioselective alcoholysis promoted by double hydrogen bond donor amine organocatalysts, resulting in their effective kinetic resolution.
- Straub, Matthew R.,Birman, Vladimir B.
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supporting information
p. 984 - 988
(2021/02/06)
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- New donor-acceptor stenhouse adducts as visible and near infrared light polymerization photoinitiators
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Polymerization photoinitiators that can be activated under low light intensity and in the visible range are being pursued by both the academic and industrial communities. To efficiently harvest light and initiate a polymerization process, dyes with high molar extinction coefficients in the visible range are ideal candidates. In this field, Donor-acceptor Stenhouse Adducts (DASA) which belong to a class of recently discovered organic photochromic molecules still lack practical applications. In this work, a series of DASA-based dyes are proposed as photoinitiators for the free radical polymerization of (meth)acrylates upon exposure to a near infrared light (laser diode at 785 nm).
- Bonardi, Aude-Héloise,Dumur, Frédéric,Duval, Sylvain,Gigmes, Didier,Lalevée, Jacques,Noirbent, Guillaume,Xu, Yangyang
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supporting information
(2020/05/28)
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- Boron/zinc exchange for the conjugate arylation of unsaturated Meldrum's acid derivatives
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An approach for the conjugate arylation reaction of unsaturated Meldrum's acid derivatives is reported. The reaction takes place through a Boron-Zinc exchange reaction between arylboronic acids and diethylzinc and the subsequent transfer of thus generated reactive aryl groups to the β-position of the double bond of the Meldrum's derivatives. The compounds obtained are valuable synthetic intermediates and can give rise to bioactive molecules such as β,β-disubstituted carboxylic acids and amides.
- Jardim, Micaela,Baldassari, Lucas L.,Contreira, Maria Eduarda,Moro, Angélica V.,Lüdtke, Diogo S.
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supporting information
(2020/01/31)
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- Enantioselective Ammonium Ylide Mediated One-Pot Synthesis of Highly Substituted γ-Butyrolactones
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An ammonium ylide mediated access towards trans-β,γ-disubstituted, all-trans-α,β,γ-trisubstituted, and α,α,β,γ-tetrasubstituted γ-butyrolactones bearing a broad variety of functionalities was developed. Starting from widely accessible benzylidene Meldrum's acid derivatives and α-bromo carbonyl compounds, γ-butyrolactones were obtained in yields between 32–99% with up to excellent diastereoselectivities (>95:5) via a DABCO-mediated [2+1] annulation. Utilization of enantiomerically pure cinchona alkaloid derivatives enables the first asymmetric ammonium ylide mediated method to provide (3R,?4R)-β,γ-disubstituted and (2R,?3R,?4R)-α,β,γ-trisubstituted γ-butyrolactones in moderate to good yields with up to very good enantiomeric ratios (97:3). The scalability of the transformation was proven while determining the absolute configuration. (Figure presented.).
- Drennhaus, Till,?hler, Laura,Djalali, Saveh,H?fmann, Svenja,Müller, Clemens,Pietruszka, J?rg,Worgull, Dennis
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supporting information
p. 2385 - 2396
(2020/04/30)
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- An alternative, practical, and ecological protocol for synthesis of arylidene analogues of Meldrum’s acid as useful intermediates
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This paper presents an ecological protocol for Knoevenagel condensation using a catalytic amount of 4,4′-trimethylenedipiperidine as a versatile, efficient, safe, commercially available, inexpensive, and recyclable organocatalyst by a ball-milling process
- Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
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- Challenges in the Development of a Thiol-Based Broad-Spectrum Inhibitor for Metallo-β-Lactamases
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Pathogens, expressing metallo-β-lactamases (MBLs), become resistant against most β-lactam antibiotics. Besides the dragging search for new antibiotics, development of MBL inhibitors would be an alternative weapon against resistant bacterial pathogens. Inhibition of resistance enzymes could restore the antibacterial activity of β-lactams. Various approaches to MBL inhibitors are described; among others, the promising motif of a zinc coordinating thiol moiety is very popular. Nevertheless, since the first report of a thiol-based MBL inhibitor (thiomandelic acid) in 2001, no steps in development of thiol based MBL inhibitors were reported that go beyond clinical isolate testing. In this study, we report on the synthesis and biochemical characterization of thiol-based MBL inhibitors and highlight the challenges behind the development of thiol-based compounds, which exhibit good in vitro activity toward a broad spectrum of MBLs, selectivity against human off-targets, and reasonable activity against clinical isolates.
- Büttner, Dominik,Kramer, Jan S.,Klingler, Franca-M.,Wittmann, Sandra K.,Hartmann, Markus R.,Kurz, Christian G.,Kohnh?user, Daniel,Weizel, Lilia,Brüggerhoff, Astrid,Frank, Denia,Steinhilber, Dieter,Wichelhaus, Thomas A.,Pogoryelov, Denys,Proschak, Ewgenij
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p. 360 - 372
(2017/12/18)
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- A practical and convenient protocol for the synthesis of (E)-α,β-unsaturated acids
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α,β-Unsaturated acids are very useful and versatile reagents in organic synthesis. A novel, practical, and convenient catalytic protocol comprising FeCl3·6H2O (0.5 mol %) and H 2O (1 equiv) in CH3NO2 is described for the rapid synthesis of α,β-unsaturated acids with high E-stereoselectivity under both microwave and conventional heating conditions with high TON and TOF values. This powerful approach efficiently demonstrated the utility of biomass derived aldehydes to build chemical agents used as fuel additives. The method proved to be scalable to gram scale synthesis.
- Mohite, Amar R.,Bhat, Ramakrishna G.
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supporting information
p. 4564 - 4567
(2013/09/24)
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- Discovery and preliminary SAR of 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6- diones as platelet aggregation inhibitors
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We herein document the discovery of 5-arylidene-2,2-dimethyl-1,3-dioxane-4, 6-diones as a novel family of platelet aggregation inhibitors. The preliminary optimization study enabled us to establish the most salient features of the structure-activity relat
- El Maatougui, Abdelaziz,Azuaje, Jhonny,Coelho, Alberto,Yaziji, Vicente,Carbajales, Carlos,Sotelo, Eddy,Lopez, Carmen,Cano, Ernesto,Yanez, Matilde
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p. 551 - 554,4
(2020/08/31)
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- Asymmetric synthesis of multi-substituted spiro[5,5]undecane-1,5,9-triones via organocatalytic three-component reaction
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The asymmetric domino three-component Knoevanagel-Diels-Alder addition (ATCDA) reaction, as an important methodology, has been utilized to construct complex product from ordinary starting materials. In this report, many typical organoamine catalysts were investigated to achieve highly efficient asymmetric three-component reaction of enones 2, aldehydes 3 and Meldrum's acid 4. Various pharmacological multi-substituted spiro[5,5]undecane-1,5,9-triones promoted by 9-amino-9-deoxy-epi-quinine 1 g in one-pot, were obtained in moderate to good yields (up to 81%) with excellent diastereo-(>99:1 dr) and enantioselectivities (up to 97% ee). Meanwhile, based on the controlled experiments and analytical data, a reasonable mechanism of dual-activity for this reaction has been proposed.
- Shi, Jian,Liu, Yangbin,Wang, Min,Lin, Lili,Liu, Xiaohua,Feng, Xiaoming
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supporting information; experimental part
p. 1781 - 1787
(2011/04/15)
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- Synthesis and biological evaluation of arylidene analogues of Meldrum's acid as a new class of antimalarial and antioxidant agents
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A series of arylidene analogues of Meldrum's acid were synthesized and evaluated for in vitro antimalarial and antioxidant activities for the first time. The influence of various physico-chemical parameters such as dielectric constant (), donor number (DN
- Sandhu, Harmeet S.,Sapra, Sameer,Gupta, Mukesh,Nepali, Kunal,Gautam, Raju,Yadav, Sunil,Kumar, Raj,Jachak, Sanjay M.,Chugh, Manoj,Gupta, Manish K.,Suri, Om P.,Dhar
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experimental part
p. 5626 - 5633
(2010/09/11)
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- A practical synthesis of α-substituted tert-butyl acrylates from meldrum's acid and aldehydes
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An expeditious synthesis of α-substituted tert-butyl acrylates from commercially available aldehydes and Meldrum's acid has been established. The method benefits from a telescoped condensation-reduction sequence to afford 5-monosubstituted Meldrum's acid
- Frost, Christopher G.,Penrose, Stephen D.,Gleave, Robert
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experimental part
p. 627 - 635
(2009/07/03)
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- Sc(OTf)3-catalyzed conjugate allylation of alkylidene meldrum's acids
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Alkylidene Meldrum's acids are allylated in a conjugate fashion by allyltin nucleophiles under mild Sc(OTf)3-catalyzed conditions. The addition is functional group tolerant and reactions with nonracemic alkylidenes are highly diastereoselective
- Dumas, Aaron M.,Fillion, Eric
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supporting information; experimental part
p. 1919 - 1922
(2009/09/25)
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- N-heterocyclic carbene-catalyzed oxidation of unactivated aldehydes to esters
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(Chemical Equation Presented) N-Heterocyclic carbenes catalyze the oxidation of unactivated aldehydes to esters with manganese(IV) oxide in excellent yield. The reaction proceeds through a transient activated alcohol, which when generated in situ allows for the selective oxidation of the aldehyde under mild conditions. These conditions successfully oxidize potentially epimerizable aldehydes and alcohols while preserving stereochemical integrity. A variety of ester derivatives can be synthesized with variation of the acylated alcohol as well as the unactivated aldehyde.
- Maki, Brooks E.,Scheldt, Karl A.
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supporting information; experimental part
p. 4331 - 4334
(2009/06/06)
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- An efficient microwave-assisted synthesis of 3,5-unsubstituted 4-substituted-6-aryl-3,4-dihydropyridin-2(1H)-ones derivatives
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(Chemical Equation Presented) Small libraries of 3,5-unsubstituted 4-substituted-6-aryl-3,4-dihydropyridin-2(1H)-ones derivatives were synthesized from the condensation-products of aldehydes with Meldrum's acid, aromatic ketones and ammonium acetate using
- Tu, Shujiang,Zhu, Xiaotong,Shi, Feng,Zhang, Jinpeng,Zhang, Yan
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p. 837 - 842
(2008/04/12)
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