- Bentonite catalyzed an efficient and green synthesis of arylidene meldrum's acid derivatives in aqueous media
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In the present paper, a simple, highly efficient, and environmentally friendly protocol was proposed for the Knoevenagel condensation reaction of aromatic aldehydes using Meldrum’s acid (2,2-dimethyl-4,6-dioxo-1,3-dioxane) with bentonite as an available n
- Yahyazadehfar, Mahdieh,Ahmadi, Sayed Ali,Sheikhhosseini, Enayatollah,Ghazanfari, Dadkhoda
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p. 513 - 519
(2021/07/25)
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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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- Microwave-associate synthesis of Co3O4 nanoparticles as an effcient nanocatalyst for the synthesis of arylidene barbituric and Meldrum's acid derivatives in green media
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In this study, Co3O4 nanocatalysts were constructed in environmentally appropriate conditions using controlled, effective, and facile microwave method. The final nanostructures were characterized by SEM, XRD, and TEM analyses. The products had a small size distribution, homogeneous morphology, and crystallographic structures associated with the formation of Co3O4 nanostructures. Moreover, EDS mapping analysis confirmed the existence of Co and O elements in the final structure, and the magnetic properties of the samples were investigated by VSM. The application of this nanostructure in a catalytic process was further examined, and the results suggested that it could be used as a novel candidate for the synthesis of arylidene barbituric and Meldrum,s acid through Knoevenagel condensation of aldehydes by barbituric and Meldrum,s acid in aqueous media. The high yield of these nanocatalysts would be justified by the nature of the nanostructure as well as the experimental procedure developed in this study, which affected the physicochemical features of the products.
- Yahyazadehfar, Mahdieh,Sheikhhosseini, Enayatollah,Ahmadi, Sayed Ali,Ghazanfari, Dadkhoda
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- A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
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A transition metal free expedient approach for the C[dbnd]C bond cleavage of electron deficient alkenes such as arylidene Meldrum's acid and malononitrile derivatives are discussed. The C[dbnd]C bond of these compound were cleaved to benzoic acid in good yield at high temperature. Most importantly, with oxone in CH3CN/H2O at 45 °C or m-CPBA in DCM or NaClO2 in THF/H2O or PIDA in THF at room temperature furnished benzaldehyde derivatives selectively in excellent yields.
- Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
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- Synthesis of bis-spiro cyclopropanes based on Meldrum's acid by milling
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Reaction of 2,2-dimethyl-1,3-dioxane-4,6-dione (Meldrum's acid) with various solid aldehydes in the presence of cyanogen bromide and solid sodium ethoxide (EtONa) leads to the selective and efficient formation of bis-spiro cyclopropanes based on Meldrum's acid at the range of 0 °C to room temperature. The products were obtained in good to excellent yields. Structure elucidation is carried out by 1H NMR, 13C NMR, FT-IR spectroscopy, mass analyses and X-ray crystallography techniques. A possible mechanism for the formation of products is also discussed under solvent-free condition.
- Kashani, Elmira,Noroozi Pesyan, Nader,Tun?, Tuncay,Sahin, Ertan
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p. 249 - 256
(2015/03/31)
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- Nickel nanoparticles catalyzed chemoselective Knoevenagel condensation of Meldrum's acid and tandem enol lactonizations via cascade cyclization sequence
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A novel protocol has been reported wherein, polyethylene glycol (PEG) stabilized nickel nanoparticles have been used as catalyst for chemoselective Knoevenagel condensation of aromatic aldehydes and Meldrum's acid to give 5-arylidene Meldrum's acid which underwent tandem enol lactonization by Michael addition/cyclization sequence with active methylene compounds in the presence of Ni nanoparticles to give corresponding enol lactone derivatives.
- Khurana, Jitender M.,Vij, Kanika
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experimental part
p. 3666 - 3669
(2011/07/29)
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- Reactions of methoxybenzylidene derivatives of 2,2-dimethyl-1,3-dioxane-4, 6-dione and their saturated analogs with certain nucleophilic reagents
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The reactions of the methoxybenzylidene derivatives of 2,2-dimethyl-1,3- dioxane-4,6-dione and their saturated analogs with potassium hydroxide in methanol, ammonia, and hydrazine hydrate were realized. The 1,2- bis(methoxybenzylidene)hydrazines, amides,
- Tetere,Ravina,Rijkure,Zicane
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scheme or table
p. 1449 - 1453
(2011/12/16)
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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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- Modular synthesis of tetrahydrofluorenones from 5-alkylidene Meldrum's acids
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The one-pot synthesis of tetrahydrofluorenones, the core 6-5-6 tricyclic structural motif found in norditerpenoid natural products, from alkylidene Meldrum's acids via thermal Diels-Alder/BF3·OEt 2-catalyzed Friedel-Crafts acylation
- Fillion, Eric,Dumas, Aaron M.,Hogg, Sylvia A.
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p. 9899 - 9902
(2007/10/03)
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