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11.
Wolfbeis Otto S. Ziegler Erich Knierzinger Andreas Wipfler Helmut Trummer Iris 《Monatshefte für Chemie / Chemical Monthly》1980,111(1):93-112
In a two step procedure and in usually good yield an -pyrone ring can be annelated to (enolized) cyclic -dicarbonyl compounds like 4-hydroxy-2-pyrones, 4-hydroxycoumarins, 4-hydroxy-2-quinolones and more complex malonylheterocycles, but also to -naphthole.In a first step the combined action of triethyl orthoformate and arylamines upon the dicarbonyl system affords the anilinomethylene derivativesB in usually high yields.B is reacted with an active methylene nitrile (like alkyl cyano-acetates) and one equivalent of a strong base (like sodium methoxide or potassium hydroxide) in a polar aprotic solvent (like dimethylformamide). Subsequent acidification with dilute aqueous acid gives the corresponding -pyroneD with yields from 18 to 84%.The reaction sequence is broadly applicable, which is demonstrated by the synthesis of a series of known (3, 7, 16, 31) and novel (10, 19, 22, 25, 28, 34) heterocyclic systems. Most of them exhibit strong fluorescence in the visible with emission maxima between 450 and 510 nm.
208. Mitt.:H. Wittmann undF. Günzl, Z. Naturforsch.33b, 1540 (1978). 相似文献
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13.
Triptycene quinones in synthesis: preparation of triptycene cyclopentenedione and its reactivity as a dienophile 总被引:1,自引:0,他引:1
Triptycenene quinone 1 was converted to triptycene cyclopentenedione 5 through hydroxyquinone-phenyliodonium ylide formation and thermal ring contraction of the latter. Cyclopentenedione 5 reacts as a dienophile and as a dipolarophile with dienes and nitrile oxides, affording polycyclic adducts bearing the triptycene moiety. 相似文献
14.
Nikoletta Sofikiti 《Tetrahedron letters》2004,45(7):1335-1337
Aryl selenides and selenoxides trap efficiently the intermediates in the reaction of singlet oxygen with sulfides. In the co-photooxygenation of 1 equiv of an aryl selenoxide with 1.3 equiv of dimethyl sulfide, the aryl selenone is formed quantitatively. Aryl selenides require 4-5 equiv of sulfide for their complete co-oxidation to selenones. 相似文献
15.
Phosphinic and phosphonic acids are useful intermediates and biologically active compounds which may be prepared from their esters, phosphinates and phosphonates, respectively, by hydrolysis or dealkylation. The hydrolysis may take place both under acidic and basic conditions, but the C-O bond may also be cleaved by trimethylsilyl halides. The hydrolysis of P-esters is a challenging task because, in most cases, the optimized reaction conditions have not yet been explored. Despite the importance of the hydrolysis of P-esters, this field has not yet been fully surveyed. In order to fill this gap, examples of acidic and alkaline hydrolysis, as well as the dealkylation of phosphinates and phosphonates, are summarized in this review. 相似文献
16.
Silke I. Nitsche Edwin Weber Wilhelm Seichter Nikoletta Báthori Kayrat M. Beketov Gerhard Roewer 《Silicon Chemistry》2003,2(1-2):55-71
New organosilicon compounds 1–3 featuring bulky triphenylsilyl moieties attached to rigid linear or trigonal spacer units have been synthesized and demonstrated to act as clathrate hosts, yielding crystalline inclusion compounds mostly with apolar and aprotic dipolar guest molecules, while the nonbulky dimethylphenylsilyl or trimethylsilyl substituted analogous compounds 4 and 5, which were also synthesized, proved inefficient. X-ray crystal structures of the inclusion compounds 1·DMF (1:1), 1·pyridine (1:1), 2·1,4-dioxane (2:1), 2·pyridine (2:1), 2·p-xylene (2:1), 2·H2O (2:1) as well as of the unsolvated compounds 2 and 5 are described, and thermal stability studies of selected clathrates are reported. 相似文献
17.
Helmut Behrens Günter Landgraf Peter Merbach Matthias Moll Karl-Heinz Trummer 《Journal of organometallic chemistry》1983,253(2):217-229
The nitrosylcarbonylisonitrile complexes η5-C5H5M(NO)(CO)CNR (R = Me for Cr, Mo, W; R = Et, SiMe3, GeMe3, SnMe3 for Mo) are formed by treatment of the nitrosylcarbonylcyanometalates Na[η5-C5H5M(NO)(CO)CN] with [R3O]BF4 (R = Me, Et), Me3SiCl, Me3GeCl or Me3SnCl. The isoelectronic dicarbonylisonitrile compounds η5-C5H5Mn(CO)2CNR (R = SiMe3, GeMe3, SnMe3, PPh2, AsMe2) and η5-C5H5Re(CO)2CNAsMe2 are obtained by analogous reactions of Na[η5-C5H5M(CO)2CN] (M = Mn, Re) with Me3ECl (E = Si, Ge, Sn), Ph2PCl and Me2AsBr.With phosgene the anionic complexes Na[η5-C5H5M(CO)2CN] (M = Mn, Re) can be transformed into the new carbonyldiisocyanide-bridged dinuclear complexes η5-C5H5M(CO)2CN-C(O)-NC(OC)2M-η5-C5H5. Finally, the reactions of η5-C5H5M(NO)(CO)CNMe (M = Cr, Mo, W) with NOPF6, leading to the cationic dinitrosylisonitrile complexes [η5-C5H5M(NO)2CNMe]+, are described. 相似文献
18.
19.
Vasiliki Palli Georgios Leonis Nikoletta Zoupanou Nikitas Georgiou Maria Chountoulesi Nikolaos Naziris Demeter Tzeli Costas Demetzos Georgia Valsami Konstantinos D. Marousis Georgios A. Spyroulias Thomas Mavromoustakos 《Molecules (Basel, Switzerland)》2022,27(8)
Losartan potassium salt (LSR) is a well-known antihypertensive drug with proven beneficial effects on human health. Its formulation with the non-toxic 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) could improve its pharmacological profile. Thus, its molecular interactions are studied using a combination of Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD). First, its complexation is shown through Differential Scanning Calorimetry as lyophilization provided distinct thermal properties in comparison to the mixture. The complexation is further proved by utilizing the chemical shift changes in the complexation and T1 values. Furthermore, the reversible favorable complexation was shown by MD calculations. Such physical chemical properties provide evidence that this formulation must be further explored through biological experiments. 相似文献
20.
L. R. Setter A. S. Goldin J. S. Nader P. K. Kuroda Y. Yokoyama P. Mazzamaro G. Tatoian J. W. Berry D. G. Chappel R. B. Barnes M. Kobrovą A. de Sousa T. F. Borovik-Romanova V. V. Korolev Ju. I. Kucenko H. Ballczo W. Schenk H. Muthenthaller H. Flaschka K. -E. Quentin R. Wickbold A. W. Busch C. N. Sawyer M. C. Rand H. Heukelekian H. S. Levine O. J. Williams L. Erdey F. Szabadváry A. Bodor Mitarb H. W. Stone P. Sigal R. L. Eichelberger O. A. Ohlweiler W. M. Shaw H. W. Hodgden R. S. Ingols A. T. Palin R. Kieselbach I. Trummer J. Janák L. Matoušek H. H. Willard A. L. Wooten 《Analytical and bioanalytical chemistry》1955,147(4):309-317