Reaktive E=C(p-p)π-Systeme, XXVIII / Reactive E=C(p-p)π-Systems, XXVIII

1991 ◽  
Vol 46 (8) ◽  
pp. 978-984 ◽  
Author(s):  
Joseph Grobe ◽  
Duc Le Van ◽  
Thomas Großpietsch

The reaction of perfluoro-2-phosphapropene F3CP=CF2 (1) with tert-butylamine or isopropylamine in a 1:3 molar ratio leads to the novel iminomethylene phosphanes F3CP=C=N(tBu) [(2), 30% yield] and F3CP=C=N(iPr) [(3), 5%], respectively. 2 slowly decomposes at room temperature giving tert-butylisonitrile and the cyclophosphanes (F3CP)n (n = 3, 4, 5). 3 is found to be less stable than 2 and for example is attacked by primary amines. The reaction of 2 with 2,3-dimethyl-1,3-butadiene or trimethylphosphane yields, on the one hand, the cycloaddition product of bis(trifluormethyl)diphosphene (4), and on the other hand, the phosphorus ylid Me3P=PCF3 (5) together with (tBu)NC.2 and 3, respectively, are not obtained from (F3C)2PH and the corresponding primary amines in a series of HF elimination and H2NR addition reactions. The main products formed from a 1:4 molar mixture of (F3C)2PH and H2N(iPr) in a one-pot procedure were shown to be the chiral phosphanes F3CP[NH(iPr)]C[=N(iPr)]H (6), F3CP[NH(iPr)]CHF2 (7) and F3CP[NH(iPr)]CH2F (8) (60:35:5). The corresponding reaction of (F3C)2PH with H2N(tBu) mainly yields the compound F3CP[NH(tBu)]CH2F (10).

2022 ◽  
Vol 16 ◽  
Author(s):  
Mustapha Dib ◽  
Marieme Kacem ◽  
Soumaya Talbi ◽  
Hajiba Ouchetto ◽  
Khadija Ouchetto ◽  
...  

Background: Pyran is an heterocyclic oxygen-containing compound that displays a wide range of therapeutic activities. Additionally, pyran is also one of the important structural subunits widely found in pharmaceuticals products. This makes it a recent focus for researchers from the industry and academic institutions. Herein, we reported an efficient and environmentally friendly one-pot strategy for the synthesis of bioactive 4H-pyran compounds via a multicomponent reaction of ethyl acetoacetate, malononitrile and substituted aromatic aldehydes in the presence of the heterogeneous spinel catalyst ( MgAl2O4 ) under mild conditions (room temperature and green solvents). The MgAl2O4 nanocatalyst was prepared from Mg/Al-LDH with a molar ratio 3 of Mg2+/Al3+ by heat treatment at 800°C. The samples were studied by a various characterization techniques such as XRD, TG-dTG, FT-IR and N2 adsorption-desorption. Good to excellent yields and facile separation of the catalyst from the reaction mixture are two of the most appealing features of this approach. Thus, bioactive molecules with pyran units may have fascinating biological properties. An efficient and green strategy for the one-pot synthesis of bioactive 4H-pyran compounds has been described. The pyrans heterocycles were produced by multicomponent reaction of ethyl acetoacetate, malononirile and substituted aromatic aldehydes in the presence of MgAl2O4 spinel nanocatalyst under mild conditions (room temperature and green solvents). MgAl2O4 nanocatalytst was prepared from Mg/Al-LDH with a molar ratio 3 of Mg2+/Al3+ by thermal treatment at 800°C. The samples were investigated by various characterization techniques such as XRD, TG-dTG, FT-IR and N2 adsorption-desorption. The following are the appealing qualities of this unique strategy including good to exceptional yields, and ease of separation of catalyst from the reaction mixture. Thus, the obtained bioactive compounds containing pyrans motif can be exhibiting interested biological activities. Methods: The substituted 4H-pyran compounds were carried out by condensation reaction of substituted aromatic aldehydes, ethyl ethyl acetoacetate and malononirile by using MgAl2O4 nanocatalyst under sustainable conditions. Objective: To develop an efficient methodology for synthesis of 4H-pyran heterocyclic molecules may have interesting applications in biology using a heterogeneous and easily synthesized catalyst. Results: This procedure outlines the synthesis of bioactive compounds in good yields and with ease of catalyst extraction from the reaction mixture under sustainable reaction conditions. Conclusion: In conclusion, it is important to reiterate that a spinel nanostucture has been successfully prepared and fully characterized using different physicochemical analysis methods. The catalytic activity of this heterogeneous catalyst was examined through the one-pot condensation of aryl benzaldehyde, malononitrile and ethyl acetoacetate. Therefore, we have developed a green method for the preparation of 4H-pyrans derivatives using MgAl2O4 as an efficient heterogeneous catalyst. The reactions were performed under green conditions, which have many benefits such as undergoing a simple procedure, good to excellent yields and easy to separate the catalyst.


2018 ◽  
Author(s):  
Huong T. D. Nguyen ◽  
Y B. N. Tran ◽  
Hung N. Nguyen ◽  
Tranh C. Nguyen ◽  
Felipe Gándara ◽  
...  

<p>Three novel lanthanide metal˗organic frameworks (Ln-MOFs), namely MOF-590, -591, and -592 were constructed from a naphthalene diimide tetracarboxylic acid. Gas adsorption measurements of MOF-591 and -592 revealed good adsorption of CO<sub>2</sub> (low pressure, at room temperature) and moderate CO<sub>2</sub> selectivity over N<sub>2</sub> and CH<sub>4</sub>. Accordingly, breakthrough measurements were performed on a representative MOF-592, in which the separation of CO<sub>2</sub> from binary mixture containing N<sub>2</sub> and CO<sub>2</sub> was demonstrated without any loss in performance over three consecutive cycles. Moreover, MOF-590, MOF-591, and MOF-592 exhibited catalytic activity in the one-pot synthesis of styrene carbonate from styrene and CO<sub>2</sub> under mild conditions (1 atm CO<sub>2</sub>, 80 °C, and solvent-free). Among the new materials, MOF-590 revealed a remarkable efficiency with exceptional conversion (96%), selectivity (95%), and yield (91%). </p><br>


2020 ◽  
pp. 182-197
Author(s):  
Agnieszka Goral

The aim of the article is to analyse the elements of folk poetics in the novel Pleasant things. Utopia by T. Bołdak-Janowska. The category of folklore is understood in a rather narrow way, and at the same time it is most often used in critical and literary works as meaning a set of cultural features (customs and rituals, beliefs and rituals, symbols, beliefs and stereotypes) whose carrier is the rural folk. The analysis covers such elements of the work as place, plot, heroes, folk system of values, folk rituals, customs, and symbols. The description is conducted based on the analysis of source material as well as selected works in the field of literary text analysis and ethnolinguistics. The analysis shows that folk poetics was creatively associated with the elements of fairy tales and fantasy in the studied work, and its role consists of – on the one hand – presenting the folk world represented and – on the other – presenting a message about the meaning of human existence.


2020 ◽  
Vol 24 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Zita Rádai ◽  
Réka Szabó ◽  
Áron Szigetvári ◽  
Nóra Zsuzsa Kiss ◽  
Zoltán Mucsi ◽  
...  

The phospha-Brook rearrangement of dialkyl 1-aryl-1-hydroxymethylphosphonates (HPs) to the corresponding benzyl phosphates (BPs) has been elaborated under solid-liquid phase transfer catalytic conditions. The best procedure involved the use of triethylbenzylammonium chloride as the catalyst and Cs2CO3 as the base in acetonitrile as the solvent at room temperature. The substrate dependence of the rearrangement has been studied, and the mechanism of the transformation under discussion was explored by quantum chemical calculations. The key intermediate is an oxaphosphirane. The one-pot version starting with the Pudovik reaction has also been developed. The conditions of this tandem transformation were the same, as those for the one-step HP→BP conversion.


SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.


1993 ◽  
Vol 48 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Joseph Grobe ◽  
Duc Le Van ◽  
Gudrun Lange

The course of the reactions o f fluorophosphaalkenes F3CP = C (F)OR [R = Me (1), Et (2)] with methanol or ethanol strongly depends on the experimental conditions. Thus at 70 °C a mixture of the 2-phosphapropionic acid ester F3CP (H )CO2R [R = Me (3), Et (4)] and trifluoromethylphosphane H2PCF3 is formed [molar ratio: 3 or 4 /H2 CF3 ≈1/1]. If the precursors F3CP (H )CO2R [R = Me (3), Et) are used as starting materials, the reaction with ROH under the same conditions affords 3 and 4, respectively, (90 to 95% yield) with only traces of H2PCF 3. In the presence o f iPr2NH these precursors react with R′OH to give the novel trifluoromethylphosphaalkenes F3CP = C (OR )OR [R /R′: Me/Me (6); E t/E t (7); Me/Et (8)]. With Et2NH , 3 undergoes an addition/elimination process yielding the interesting push/pull system Et2N(F)C = P-CO2Me (5). 1 and 2 react with primary amines R′NH2 (R′= tBu, Me) with stereoselective formation of the fairly labile phosphaalkenes F3CP = C(OR)NHR′ [R /R′: Me/tBu (9), Et/tBu(10), Me/Me (11)] with trans-positions for CF3 and NHR′.The new compounds 3 -11 were characterized by spectroscopic investigations (1H , 19F, 31P, 13C NMR ; IR, MS) and determination of M+ or typical fragment ions [M+ -OR ] by high resolution mass spectrometry.


RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 67281-67289 ◽  
Author(s):  
Ali Khalafi-Nezhad ◽  
Mohsen Shekouhy ◽  
Hashem Sharghi ◽  
Jasem Aboonajmi ◽  
Abdolkarim Zare

A new more atom-efficient multi-component approach for the synthesis of tetrasubstituted imidazoles via the one-pot condensation of nitriles, primary amines and benzoin has been described.


PMLA ◽  
1967 ◽  
Vol 82 (1) ◽  
pp. 14-27
Author(s):  
Leon F. Seltzer

In recent years, The Confidence-Man: His Masquerade, a difficult work and for long an unjustly neglected one, has begun to command increasingly greater critical attention and esteem. As more than one contemporary writer has noted, the verdict of the late Richard Chase in 1949, that the novel represents Melville's “second best achievement,” has served to prompt many to undertake a second reading (or at least a first) of the book. Before this time, the novel had traditionally been the one Melville readers have shied away from—as overly discursive, too rambling altogether, on the one hand, or as an unfortunate outgrowth of the author's morbidity on the other. Elizabeth Foster, in the admirably comprehensive introduction to her valuable edition of The Confidence-Man (1954), systematically traces the history of the book's reputation and observes that even with the Melville renaissance of the twenties, the work stands as the last piece of the author's fiction to be redeemed. Only lately, she comments, has it ceased to be regarded as “the ugly duckling” of Melville's creations. But recognition does not imply agreement, and it should not be thought that in the past fifteen years critics have reached any sort of unanimity on the novel's content. Since Mr. Chase's study, which approached the puzzling work as a satire on the American spirit—or, more specifically, as an attack on the liberalism of the day—and which speculated upon the novel's controlling folk and mythic figures, other critics, by now ready to assume that the book repaid careful analysis, have read the work in a variety of ways. It has been treated, among other things, as a religious allegory, as a philosophic satire on optimism, and as a Shandian comedy. One critic has conveniently summarized the prevailing situation by remarking that “the literary, philosophical, and cultural materials in this book are fused in so enigmatic a fashion that its interpreters have differed as to what the book is really about.”


2020 ◽  
Vol 12 (4) ◽  
pp. 443-454

Sons and Lovers (1913) is one of D.H. Lawrence’s most prominent novels in terms of psychological complexities characteristic of most, if not all, of his other novels. Many studies have been conducted on the Oedipus complex theory and psychological relationship between men and women in Lawrence’s novels reflecting the early twentieth century norms of life. This paper reexamines Sons and Lovers from the perspective of rivalry based on Alfred Adler’s psychological studies. The discussion tackles the sibling rivalry between the members of the Morels and extends to reexamining the rivalry between other characters. This concept is discussed in terms of two levels of relationships. First, between Paul and William as brothers on the one hand, and Paul and father and mother, on the other. Second, the rivalry triangle of Louisa, Miriam and Mrs. Morel. The qualitative pattern of the paper focuses on the textual analysis of the novel to show that Sons and Lovers can be approached through the concept of rivalry and sibling Rivalry. Keywords: Attachment theory, Competition, Concept of Rivalry, Favoritism, Sibling rivalry.


Genre ◽  
2021 ◽  
Vol 54 (2) ◽  
pp. 195-219
Author(s):  
Liz Shek-Noble

Alexis Wright's second novel, Carpentaria, received critical acclaim upon its publication by Giramondo in 2006. As the recipient of the Miles Franklin Literary Award in 2007, Carpentaria cemented Wright's position as the country's foremost Indigenous novelist. This article places Carpentaria within contemporary discussions of “big, ambitious novels” by contemporary women novelists by examining the ways the novel simultaneously invites and resists its inclusion into an established canon of “great Australian novels” (GANs). While critics have been quick to celebrate the formal innovations of Carpentaria as what makes it worthy of GAN status, the novel nevertheless opposes the integrationist and homogenizing myths that accompany canonization. Therefore, the article finds that Wright's vision of a future Australia involves moments of antagonism and mutual understanding between white settler and Indigenous communities. This article uses the work of Homi Bhabha to argue that Carpentaria demonstrates the emergence of a third space wherein negotiation between these two cultures produces knowledge that is “new, neither the one nor the other.” In so doing, Wright shows the resilience of Indigenous knowledge even as it is subject to transformation upon contact with contradictory ideological and epistemological frameworks.


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