15795-57-0Relevant articles and documents
Bentonite catalyzed an efficient and green synthesis of arylidene meldrum's acid derivatives in aqueous media
Yahyazadehfar, Mahdieh,Ahmadi, Sayed Ali,Sheikhhosseini, Enayatollah,Ghazanfari, Dadkhoda
, p. 513 - 519 (2021/07/25)
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
Enantioselective Ammonium Ylide Mediated One-Pot Synthesis of Highly Substituted γ-Butyrolactones
Drennhaus, Till,?hler, Laura,Djalali, Saveh,H?fmann, Svenja,Müller, Clemens,Pietruszka, J?rg,Worgull, Dennis
supporting information, p. 2385 - 2396 (2020/04/30)
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.).
An alternative, practical, and ecological protocol for synthesis of arylidene analogues of Meldrum’s acid as useful intermediates
Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
, (2019/03/17)
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
Microwave-associate synthesis of Co3O4 nanoparticles as an effcient nanocatalyst for the synthesis of arylidene barbituric and Meldrum's acid derivatives in green media
Yahyazadehfar, Mahdieh,Sheikhhosseini, Enayatollah,Ahmadi, Sayed Ali,Ghazanfari, Dadkhoda
, (2019/08/02)
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.
A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
, (2019/09/10)
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.
With the plaque and A β of the nerve fiber entanglement having affinity to the compound and its preparation method
-
Paragraph 0131-0132, (2018/04/26)
The invention provides a compound provided with good affinity and tangled with an Abeta plaque and a nerve fiber. The structural general formula (I) of the compound is as shown in the specification, wherein W is a benzo-hexahydric aromatic ring or a hexah
Synthesis of bis-spiro cyclopropanes based on Meldrum's acid by milling
Kashani, Elmira,Noroozi Pesyan, Nader,Tun?, Tuncay,Sahin, Ertan
, p. 249 - 256 (2015/03/31)
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.
Di- and triarylmethylium ions as probes for the ambident reactivities of carbanions derived from 5-benzylated Meldrum's acid
Chen, Xi,Tan, Yue,Berionni, Guillaume,Ofial, Armin R.,Mayr, Herbert
, p. 11069 - 11077 (2014/10/15)
The kinetics of the reactions of carbocations with carbanions 1 derived from 5-benzyl-substituted Meldrum's acids 1-H (Meldrum's acid=2,2-dimethyl-1,3- dioxane-4,6-dione) were investigated by UV/Vis spectroscopic methods. Benzhydryl cations Ar2CH+ added exclusively to C-5 of the Meldrum's acid moiety. As the second-order rate constants (kC) of these reactions in DMSO followed the linear free-energy relationship lg k=s N(N+E), the nucleophile-specific reactivity parameters N and s N for the carbanions 1 could be determined. In contrast, trityl cations Ar3C+ reacted differently. While tritylium ions of low electrophilicity (E-2) reacted with 1 through rate-determining β-hydride abstraction, more Lewis acidic tritylium ions initially reacted at the carbonyl oxygen of 1 to form trityl enolates, which subsequently reionized and eventually yielded triarylmethanes and 5-benzylidene Meldrum's acids by hydride transfer.
Synthesis of new guanidium-meldrum acid zwitterionic salts and dynamic NMR study of rotational energy barrier around C-NH bond of guanidine moiety
Aminkhani, Ali
, p. 1791 - 1797 (2015/04/27)
Synthesis of the Guanidium-Meldrum acid zwitterionic salts was developed through a three component reaction of 2, 2-dimethyl-1, 3-dioxane-4, 6-dione (Meldrum acid), aromatic aldehydes and N, N, N', N'- Tetramethyl-guanidine in benzen at room temperature.
Nickel nanoparticles catalyzed chemoselective Knoevenagel condensation of Meldrum's acid and tandem enol lactonizations via cascade cyclization sequence
Khurana, Jitender M.,Vij, Kanika
experimental part, p. 3666 - 3669 (2011/07/29)
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.
