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1.
Adel A.-H. Abdel-Rahman Ahmed E.-S. Abdel-Megied Mohamed A. M. Hawata Eman R. Kasem Mohamed T. Shabaan 《Monatshefte für Chemie / Chemical Monthly》2007,16(6):889-897
Chalcones were synthesized by a base catalyzed Claisen-Schmidt condensation reaction. Bromination of chalcones afforded the dibromo derivatives. Monobromo derivatives could be obtained
by treating the corresponding dibromochalcones with dry benzene in the presence of triethylamine. Pyrazole derivatives were
obtained by refluxing of dibromochalcones with phenylhydrazine or 2,4-dinitrophenylhydrazine in dry pyridine. Chalcones were
treated with hydrazine hydrate or phenyl hydrazine in ethanol to afford Δ
2-pyrazolines and N-phenyl-Δ
2-pyrazolines. Condensation of chalcones with hydroxylamine hydrochloride or thiourea in ethanolic sodium hydroxide solution
gave 4,5-dihydroisoxazoles and 5,6-dihydropyrimidine-2-(1H)-thiones. The prepared compounds were tested for antimicrobial activity against four different bacterial species displaying
different degrees of antibacterial activities or inhibitory actions. 相似文献
2.
Summary. A series of 1,5-disubstituted 3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines were synthesized by the reaction of α,β-unsaturated ketones derived from dehydroacetic acid and
hydrazine in hot acetic acid or propionic acid. The structures of all new compounds were elucidated by microanalyses, 1H and 13C NMR, IR, and mass spectroscopic measurements. 相似文献
3.
Hyuk Yoon Seunghyun Ahn Mijoo Park Dong‐Wook Kim Sang Ho Kim Dongsoo Koh Yoongho Lim 《Magnetic resonance in chemistry : MRC》2013,51(8):500-508
Chalcones are known to act on various physiological targets. As a result, structural modifications of chalcones have been studied extensively. Benzochalcones, in which the A‐ring of chalcone is substituted with a naphthalene unit, inhibits breast cancer resistance protein. Chalcones in which the α,β‐unsaturated carbonyl group is switched with a pyrazoline moiety are potent cytotoxic agents against various cancer cell lines, and chalcones with a pyrazoline‐1‐carbothioamide group instead of an α,β‐unsaturated carbonyl group exhibit antimicrobial activities. The present report describes hybrid molecules designed from benzochalcone and pyrazoline–carbothioamide. Methoxylation of plant‐derived polyphenols alters their hydrophobicity, resulting in changes in biological function and intracellular compartmentation. In the current study, 22 novel methoxylated 3‐(naphthalen‐2‐yl)‐N,5‐diphenyl‐pyrazoline‐1‐carbothioamide derivatives were prepared. This report provides complete assignments of their 1H and 13C NMR data, which can be used to subsequently identify chalcones bearing pyrazoline–carbothioamide groups. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
4.
A series of 1,5-disubstituted 3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines were synthesized by the reaction of α,β-unsaturated ketones derived from dehydroacetic acid and
hydrazine in hot acetic acid or propionic acid. The structures of all new compounds were elucidated by microanalyses, 1H and 13C NMR, IR, and mass spectroscopic measurements. 相似文献
5.
V. F. Lavrushin S. V. Tsukerman E. G. Buryakovskaya 《Chemistry of Heterocyclic Compounds》1965,1(5):465-468
Nineteen 2-pyrazolines hitherto undescribed in the literature are prepared by reacting thiophene and selenophene analogs of chalcones with phenylhydrazine or p-nitrophenylhydrazine. It is shown that thiophene and selenophene chalcones can be more easily cyclized than their furan analogs. The 2, 4, 6-trimethoxy group when present in the 1-(thienyl-2)-3-arylpropenone-1 molecule causes steric hindrance in the corresponding pyrazoline. 相似文献
6.
V. F. Lavrushin S. V. Tsukerman E. G. Buryakovskaya 《Chemistry of Heterocyclic Compounds》1966,1(3):211-214
Furan analogs of chalcones are condensed with phenylhydrazine to give a number of 2-pyrazolines hitherto not described in the literature. It is shown that in , -unsaturated ketones, a nitro-group in the nucleus and remote from the carbonyl group makes cyclization to the corresponding 2-pyrazolines more difficult than does one adjacent to the carbonyl. 相似文献
7.
Action of Hydrazines on 2‐(2‐Oxindolin‐3‐ylidene)malononitrile, (E,Z)‐Ethyl 2‐cyano‐2‐(2‐oxindolin‐3‐ylidene)acetate and Isatin‐β‐thiosemicarbazone as a Source of Spiro Indoline‐pyrazole Systems
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Ahmed S. A. Youssef Magdy M. Hemdan Samir A. Emara Rabaa M. Kamel 《Journal of heterocyclic chemistry》2015,52(5):1331-1336
2‐(2‐Oxindolin‐3‐ylidene)malononitrile ( 1a ) or (E,Z)‐ethyl 2‐cyano‐2‐(2‐oxindolin‐3‐ylidene)acetate ( 1b ) or isatin‐β‐thiosemicarbazone ( 1c ) undergoes reactions with prototype hydrazine hydrate itself and some of its simple congeners to give hydrazone derivatives bearing indoline‐2‐one moiety ( 2 ). The hydrazone derivatives ( 2 ) when heated with acetyl acetone or ethyl acetoacetate in dry pyridine afforded the spiro indoline derivatives ( 3a , 3b ). Also, cinnoline derivative ( 9 ) is obtained by action of hydrazine hydrate on the N‐acetyl derivative of ( 6a ). The structures of the newly synthesized compounds were evaluated by IR, 1H‐NMR spectroscopy, mass spectra and elemental analyses. 相似文献
8.
The 2-pyrazolines synthesized under the usual conditions from unsaturated aldehydes and hydrazine contain from 2 to 3% of the 1-isomers and considerable amounts of the isomeric 3-alkyl-2-pyrazolines, which are formed as a consequence of migration of the double bond. Mixtures of the stereoisomeric 2-pyrazolines are formed from ,-dialkyl-substituted acroleins. Migration of the double bond does not occur in the condensation of unsaturated ketones with hydrazine, and 2-pyrazolines that are free from admixtures of the structural isomers are obtained.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1225–1229, September, 1971. 相似文献
9.
L. A. Trukhacheva V. I. Levina N. B. Grigor’ev A. P. Arzamastsev I. L. Dalinger I. A. Vatsadze G. P. Popova S. A. Shevelev V. G. Granik 《Russian Chemical Bulletin》2005,54(12):2813-2819
Alkaline hydrolysis of mono-and dinitro derivatives of five-membered heterocycles, viz., pyrazole, imidazole, 1,2,4-triazole, and isoxazole, is accompanied by the elimination of the nitro group in the form of
a nitrite anion. The hydrolysis kinetics was studied by the polarographic and photometric methods. The experimentally determined
hydrolysis rate constants depend on the nature of the heterocycle. A possible mechanism for hydrolytic transformations of
the compounds under study was proposed on the basis of the calculated thermodynamic parameters of the reaction (Δ G
≠, ΔH
≠, ΔS
≠).
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2719–2725, December, 2005. 相似文献
10.
Yeonjoong Yong Seunghyun Ahn Doseok Hwang Hyuk Yoon Geunhyeong Jo Young Hwa Kim Sang Ho Kim Dongsoo Koh Yoongho Lim 《Magnetic resonance in chemistry : MRC》2013,51(6):364-370
Chalcones are of interest to medicinal chemists because their structures can be easily modified with various functional groups. The syntheses and biological activities of chalcones from natural sources are well known. In this study, 24 2′‐hydroxychalcones bearing methoxy substituents were synthesized, among which five are new. The NMR data for all synthesized chalcones are described for the first time. The complete assignments of the 1H and 13C NMR data can be used for the identification of newly discovered and widely isolated, synthesized chalcones. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
11.
A. I. Lytkin N. V. Chernyavskaya V. E. Litvinenko 《Russian Journal of Coordination Chemistry》2011,37(12):893-896
The enthalpies of complexation between N,N-bis(carboxymethyl)aspartic acid (H4Y) and the Pb2+ ion at 298.15 K were determined from calorimetric data for a wide range of the ionic strengths (KNO3). The thermodynamic characteristics ΔH, ΔG, and ΔS, of formation of the complexes PbHY− and PbY2− were calculated for zero and fixed ionic strengths. The results obtained were interpreted. 相似文献
12.
Seyed Majid Hashemianzadeh Shirin Faraji Amir Hossein Amin Sepideh Ketabi 《Monatshefte für Chemie / Chemical Monthly》2008,139(2):89-100
Summary. Interactions of the DNA bases adenine (A), guanine (G), cytosine (C), and thymine (T) with various metal ions (M) of groups IA and IIA of the periodic table of the elements were studied at the HF, MP2, and DFT levels of theory. The structures and thermodynamic stabilities of these species were studied at the gas phase. The calculations
uphold that there exist two active sites in G and one in A, C, and T. The calculations also show that the O2 atom in T is a more active site for metal ion bindings than that in C. The stability energies for G … M complexes are larger than those for A … M complexes and the stability energies for T … M complexes are larger than those for C … M complexes. As z/r ratio for the metal ion increases, the interaction energy for the complex increases systematically. Thermodynamic quantities
such as ΔH, ΔG, ΔS, and ln K were determined for each complexation reaction, [Base+M
n+ →(Base … M)
n+]. A, G, and C complexation reactions except for C … Rb+ are exothermic. The situation is quite different for T complexation reactions and all except for T … Be2+ and T … Mg2+ are endothermic. 相似文献
13.
Polyfluoroalkyl-containing bispyrazoles, bis(5-hydroxy-Δ2-isoxazolines), and bisisoxazoles were synthesized for the first time by reactions of polyfluoroalkyl-containing bis-β-diketones
with hydrazine, phenylhydrazine, and hydroxylamine, respectively.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 762–764, April, 1999. 相似文献
14.
Enthalpies of Dehydrations of Oxalate,Sulfate and Chloride Hydrates by Transpiration Method and DSC 总被引:2,自引:0,他引:2
Transpiration method was used to measure the equilibrium water vapor pressures of the dehydration of the respective hydrates,
such as oxalates, sulfates,chlorides and acetate, and the enthalpies of dehydrations (ΔH
Tr
0) of these hydrates were obtained. The heats of dehydrations (ΔH
DSC
0) were also determined by TG-DSC method. From the comparison with ΔH
Tr
0 of ΔH
DSC
0, the relation of ΔH
DSC
0/ΔH
Tr
0=R (=dehydration molar number determined by TG-DSC peak/stoichiometric dehydration molar number) was yielded. From these results,
the following relations were found: ΔH
DSC
0(corrected)=ΔH
DSC
0/R=ΔH
Tr
0
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
V. V. Vashchenko N. S. Pivnenko L. A. Kutulya A. S. Petrenko S. V. Iksanova J. W. Goodby 《Russian Chemical Bulletin》2000,49(7):1218-1230
1R,4R-2-(4-Phenylbenzylidene)-p-menthan-3-one in acidic media undergoes rearrangement with migration of the exocyclic double bond to the cyclohexane ring to form three 2-(4-phenylbenzyl) derivatives ofp-menthen-3-ones. The reaction products differ in the location of the endocyclic double bond (Δ1 or Δ4) and in the configuration of the new chiral C(2) center in the resultingp-menth-4-en-3-ones. The configurations of the 1R,2R- and 1R,2S-2-(4-phenylbenzyl)-p-menth-4-en-3-ones were established based on analysis of their1H NMR spectra in combination with calculations by molecular mechanics. The molecular conformations of these compounds as well as of some racemic 2-benzyl-p-menth-1-en-3-one derivatives were studied. 相似文献
16.
Heinz Gamsjäger Wolfgang Preis Harald Wallner 《Monatshefte für Chemie / Chemical Monthly》2001,132(3):411-415
Summary. The solubility of hellyerite, NiCO3 · 6H2O, in water was studied at different temperatures. From the experimental data obtained, a preliminary set of the thermodynamic
quantities Δf
G
⊖, Δf
H
⊖, and S
⊖ for hellyerite was derived using the ChemSage optimizer routine.
Received January 16, 2001. Accepted January 18, 2001 相似文献
17.
G. G. Gorboletova S. N. Gridchin A. A. Lutsenko 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(11):1856-1861
Heats of the interaction of Cu(NO3)2 solutions with L-glutamine solutions were measured directly by calorimetry at a temperature of 298.15 K and ionic strength
values of 0.5, 1.0, and 1.5 (KNO3). Using RRSU universal software, the experimental data were subjected to rigorous mathematical treatment with allowances
made for several concurrent processes in the system. The heats of formation of the CuL+ and CuL2 complexes were calculated from the calorimetric measurements. The standard heats of the complex formation of Cu2+ with L-glutamine were obtained by extrapolation to zero ionic strength. The complete thermodynamic characteristic (Δr
H
o, Δr
G
o, Δr
S
o) of the complex formation processes in a Cu2+—L-glutamine system was obtained. 相似文献
18.
The isomeric composition of the 2-pyrazolines obtained by the condensation of croton aldehyde and methyl vinyl ketone with C1–C4 monoalkyl hydrazines has been studied by the GLC method. It has been shown that in the reaction of croton aldehyde with isopropyl hydrazine, isobutyl hydrazine, and, to a smaller extent, with methyl hydrazine, in addition to the 1-alkyl-5-methyl-2-pyrazolines the 1, 3-isomers are formed. In other cases, only one pyrazoline, corresponding to the structure of the carbonyl compound, is formed. Eight previously-unknown dialkyl-2-pyrazolines are described. 相似文献
19.
《Journal of heterocyclic chemistry》2017,54(4):2536-2547
A novel series of bis(3‐thienyl‐4,5‐dihydropyrazoles) has been synthesized by the cyclization reactions of bischalcones with phenyl hydrazine in basic medium. The O‐alkylation reactions of chalcones with suitable 1,ω‐dibromoalkanes in the presence of anhydrous K2CO3, dry acetone, and Bu4N+I− as PTC lead to the formation of bischalcones in good yields. The chalcone required was obtained from the Claisen–Schmidt condensation reaction of 2‐acetylthiophene with 3‐hydroxybenzaldehyde. Structures of prepared compounds were elucidated from their IR, 1H‐NMR, 13C‐NMR, and ESI‐MS spectral data. Newly synthesized compounds were screened for their antimicrobial potencies against Gram‐positive, Gram‐negative bacterial strains, and fungal strains using serial tube dilution method. Docking simulations have also been carried out to visualize the possible interaction of synthesized scaffold 2(a – g) and 3(a – g) at the active sites of Escherichia coli . 相似文献
20.
Muhammad A. Motin Tapan K. Biswas Entazul M. Huque 《Monatshefte für Chemie / Chemical Monthly》2003,134(4):475-487
Summary. Density and viscosity of NaNO3 and KNO3 in aqueous and in H2O-urea solutions were determined as a function of electrolyte concentrations at 308, 313, 318, 323, and 328 K, respectively.
The apparent molal volume (φ
v
) of the electrolytes were found to be linear functions of the square root of the solute molality (b). The φ
v
and data were fitted to the Masson equation [1] by the least square method to obtain the apparent molar volume at infinite dilution (φ
v
^), which is practically equal to the partial molar volume . The viscosity coefficients A and B were calculated on the basis of the viscosity of the solutions and the solvent concerned using the Jones–Dole [2] equation. The activation parameters for viscous flow (ΔG
≠, ΔS
≠, and ΔH
≠) were calculated according to Eyring [3]. The values of for the two systems were also calculated from B-coefficient data. The results were found to be of opposite nature in the two electrolyte systems. Where sodium nitrate showed
structure making behaviour both in aqueous and in H2O-urea solutions, KNO3 showed structure breaking behaviour in aqueous solutions and structure making behaviour in 5 molal H2O-urea solutions in the studied temperature range. The behaviour of these two electrolytes in aqueous binary and in aqueous-urea
ternary systems are discussed in terms of charge, size, and hydrogen bonding effects.
Corresponding author. E-mail: chemistry_ru@yahoo.com
Received January 24, 2002; accepted (revised) April 5, 2002 相似文献