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1.
Vera L. M. Silva Artur M. S. Silva Diana C. G. A. Pinto José A. S. Cavaleiro Attila Vasas Tamás Patonay 《Monatshefte für Chemie / Chemical Monthly》2008,139(11):1307-1315
Several (E)- and (Z)-3-styrylchromones were prepared by two different methodologies, the Wittig reaction of chromone-3-carboxaldehyde with benzylic ylides and the Knoevenagel condensation of chromone-3-carboxaldehyde with phenylacetic acids in the presence of potassium tert-butoxide under microwave irradiation. The Knoevenagel reaction followed by a decarboxylation offered an efficient and diastereoselective method for preparing (E)-3-styrylchromones in a shorter reaction time. It was also demonstrated that phenylacetic acid can also be substituted with
success by phenylmalonic acid. The stereochemistry of all products was assigned by NMR experiments.
Correspondence: Artur M. S. Silva, Chemistry Department, University of Aveiro, 3810-193 Aveiro, Portugal. 相似文献
2.
Vera L. M. Silva Artur M. S. Silva Diana C. G. A. Pinto José A. S. Cavaleiro José Elguero 《Monatshefte für Chemie / Chemical Monthly》2009,45(2):87-95
Abstract
An efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations is discussed and the stereochemistries of all products were established by NMR experiments. 相似文献3.
An efficient synthetic method for the preparation of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles has been developed. The reaction of (E)- and (Z)-3-styrylchromones with hydrazine hydrate afforded the corresponding (E)- and (Z)-4-styrylpyrazoles, respectively, saved 4′-nitro-derivatives where both (E)- and (Z)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations was discussed and the stereochemistry of all products was assigned by NMR experiments. 相似文献
4.
Vera L. M. Silva Artur M. S. Silva Diana C. G. A. Pinto José A. S. Cavaleiro José Elguero 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):87-95
Abstract An efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles. The reaction mechanism for these transformations is discussed and the
stereochemistries of all products were established by NMR experiments.
Graphical abstract
相似文献
5.
N. V. Kovganko S. N. Sokolov Yu. G. Chernov A. V. Baranovskii 《Chemistry of Natural Compounds》2011,47(4):592-596
(Z)- and (E)-3-(2-chloropyridin-5-ylmethyl)oximino-(22E,24R)-ergosta-4,7,22-trienes (5–6) were synthesized by chemical transformation of ergosterol. Several oxidative transformations of them were studied. It was
found that oxidation of these compounds by chromium(VI) oxide formed the corresponding O-substituted 3-ketoximes of the mycosteroid (22E,24R)-ergosta-4,7,22-trien-3,6-dione (7) and (8), which contained α-chloropyridine fragments characteristic of biologically active neonicotinoids. It was shown that oxidation of 5 and 6 by selenium dioxide occurred with formation of the corresponding 9α-hydroxy derivatives 9 and 10. 相似文献
6.
Diana T. Patoilo Artur M.S. Silva Diana C.G.A. Pinto Clementina M.M. Santos Augusto C. Tomé José A.S. Cavaleiro 《Tetrahedron letters》2012,53(22):2722-2725
The Diels–Alder reaction of (E)-2-styrylchromones with a pyrimidine ortho-quinodimethane is reported for the first time. These cycloaddition reactions afford mixtures of two regioisomeric tetrahydroquinazoline-substituted chromones in moderate to excellent global yields. Irrespective of the substituents on the 2-styrylchromones, the 2-(7-aryl-4-methoxy-2-methyl-5,6,7,8-tetrahydroquinazolin-6-yl)chromone derivatives are always the major isomers. 相似文献
7.
Magdy A. Ibrahim 《Tetrahedron》2009,65(36):7687-2859
4-Hydroxycoumarin-3-carboxaldehyde (5) was obtained from chromone-3-carboxaldehyde (1) via chromone-3-carboxamide (2) and 3-aminomethylene-2H-chroman-2,4-dione (3). 3-Alkylaminomethylenechroman-2,4-diones (7,8) were obtained from the reaction of primary aliphatic amines with chromone-3-carboxamide (2). Treatment of chromone-3-carboxamide with sodium methoxide gives 3-(2-hydroxybenzoyl)-2H-chromeno[2,3-b]pyridine-2,5(1H)-dione (9). 相似文献
8.
The conversion of chromone-3-carboxaldehyde to 5-nitro-2,3-benzofurandione-()-2-oxime under nitrating conditions is reported. 相似文献
9.
6-Methyl-6-hepten-2-one (3) on reaction with ethyl α-dimethylphosphonate/NaH gives a mixture of (E)-and (Z)-conjugated esters. The major (E)-isomer, (E)-ethyl-3,7-dimethyl-2,7-octadienoate (4), on reduction with LiAlH4 at room temperature furnishes (E)-3,7-dimethyl-2,7-octadien-l-ol (5) which on propionylation affords (E)-3,7-dimethyl-2,7-octadienyl propionate (1). Carbinol (5) is converted into its silyl ether (E)-2,6-dimethyl-8-t-butyldimethylsilyloxy-l,6-octadiene (6) witht-Bu(Me)2SiCl in CH2Cl2, which on hydroboronation-oxidation with 9-BBN/NaOH-H2O2 followed by disilylalion with (n-Bu)4N+ F− at room temperature, gives (E)-3,7-dimethyl-2-octen-l,8-diol (2). 相似文献
10.
Artur M. S. Silva Judite S. Vieira Cristela M. Brito José A. S. Cavaleiro Tamás Patonay Albert Lévai José Elguero 《Monatshefte für Chemie / Chemical Monthly》2004,16(10):293-308
The bromination of 2-styrylchromones, bearing electron neutral substituents, with two molar equivalents of piridinium tribromide gave 2-(2-aryl-1,2-dibromoethyl)chromones and 3-bromo-2-(2-aryl-1,2-dibromoethyl)chromones. The presence of electron-donating substituents on their B ring led to a mixture of compounds due to the higher reactivity of their C(2)=C(3) and C=C double bonds, whereas the strongly electron-withdrawing group hindered the bromination. The dehydrobromination of 2-(2-aryl-1,2-dibromoethyl)chromones with triethylamine gave a diastereomeric mixture of (E)- and (Z)-2-(-bromostyryl)chromones. Some novel 4(5)-aryl-5(4)-(2-chromonyl)-1,2,3-triazoles have been obtained from the reactions of 2-(2-aryl-1,2-dibromoethyl)chromones, 2-(-bromostyryl)chromones, and 2-styrylchromones with sodium azide. The reactions of 2-styrylchromones with sodium azide are more efficient, general, and constitute a one-pot synthetic method of 4(5)-aryl-5(4)-(2-chromonyl)-1,2,3-triazoles allowing the preparation of 1,2,3-triazoles bearing either electron-donating or electron-withdrawing substituents in their aryl ring. The structure of all new compounds was established by extensive NMR spectroscopic studies. 相似文献
11.
A series of phenyl azides bearing (E)-2-halovinyl groups were synthesized in high yields by treatment of (E)-3-(4-azidophenyl)- and (E)-3-(2-azidophenyl)acrylic acid with N-halosuccinimide in the presence of LiOAc. (E)-4-(2-bromovinyl) phenyl azide, one of the synthesized intermediates, was selected to transform to a diverse range of phenyl-1,
2, 3-triazoles bearing (E)-4-(2-bromovinyl) groups by Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction. 相似文献
12.
Artur M. S. Silva Judite S. Vieira Cristela M. Brito José A. S. Cavaleiro Tamás Patonay Albert Lévai José Elguero 《Monatshefte für Chemie / Chemical Monthly》2004,135(3):293-308
Summary. The bromination of 2-styrylchromones, bearing electron neutral substituents, with two molar equivalents of piridinium tribromide gave 2-(2-aryl-1,2-dibromoethyl)chromones and 3-bromo-2-(2-aryl-1,2-dibromoethyl)chromones. The presence of electron-donating substituents on their B ring led to a mixture of compounds due to the higher reactivity of their C(2)=C(3) and C=C double bonds, whereas the strongly electron-withdrawing group hindered the bromination. The dehydrobromination of 2-(2-aryl-1,2-dibromoethyl)chromones with triethylamine gave a diastereomeric mixture of (E)- and (Z)-2-(-bromostyryl)chromones. Some novel 4(5)-aryl-5(4)-(2-chromonyl)-1,2,3-triazoles have been obtained from the reactions of 2-(2-aryl-1,2-dibromoethyl)chromones, 2-(-bromostyryl)chromones, and 2-styrylchromones with sodium azide. The reactions of 2-styrylchromones with sodium azide are more efficient, general, and constitute a one-pot synthetic method of 4(5)-aryl-5(4)-(2-chromonyl)-1,2,3-triazoles allowing the preparation of 1,2,3-triazoles bearing either electron-donating or electron-withdrawing substituents in their aryl ring. The structure of all new compounds was established by extensive NMR spectroscopic studies. 相似文献
13.
Lijun Peng Jiantao Wang Chuanmin Sun Zhongquan Liu Longmin Wu 《Tetrahedron: Asymmetry》2008,19(17):2078-2083
N-Nitrosation of (E)-(S)-2-(benzylidene-amino)ethanols 2 with nitric oxide occurred highly diastereoselectively, to give the (2S,4S)-diastereomer dominant N-nitroso-(2S,4S)-1,3-oxazolidines in good yield. Intermediate 2 was prepared from the reaction of benzaldehyde 1 with (S)-2-aminoethanol. 相似文献
14.
(±-(2E,4E)-2,7-Dimethylocta-2,4-dienedioic acid ( 1 ) was synthesized efficiently from furan, employing a rhodium-carbenoid-induced furan-ring-unravelling reaction followed by an unusual NaBH4/CeCl3⋅7 H2O reduction, Wittig-Horner olefination, and diester hydrolysis. 相似文献
15.
Keigo Kosaka Kazumi Maruyama Haruko Nakamura Masazumi Ikeda 《Journal of heterocyclic chemistry》1991,28(8):1941-1944
Diels-Alder reaction of methyl (E)-3-(1H-imidazol-4-yl)propenoates 2, 3a-c and (E)4-(2-nitroethenyl)-1H-imidazoles 3d,e with 2,3-dimethyl-1,3-butadiene, cyclopentadiene, and cyclohexa-1,3-diene gave the corresponding cycloadducts 6–9 . 相似文献
16.
Charles W. Jefford Jean-Claude Rossier John Boukouvalas Pingzhong Huang 《Helvetica chimica acta》1994,77(3):661-667
The first synthesis of (Z)-neomanoalide ( 4 ) and an improved synthesis of its (E)-isomer 3 was accomplished in a concise, regiocontrolled manner by exploiting 2-[(tert-butyl)dimethylsiloxy]-4{[(tert-butyl)dimethylsiloxy]-methyl}furan ( 6 ) as the key reagent. Lithiation of 6 and subsequent reaction with the (2Z)- or (2E)-isomer of (6E)-3-{[(tert-butyl)dimethylsiloxy]methyl}-7-methyl-9-(2′,6′,6′-trimethylcyclohex-1′-enyl)nona-2,6-dienyl bromide ( 5 ), followed by hydrolysis, afforded the corresponding neomanoalide. 相似文献
17.
Keitaro Ishii Peter Mathies Takehiko Nishio Hans Richard Wolf Bruno Frei Oskar Jeger 《Helvetica chimica acta》1984,67(5):1175-1183
The title compounds (E/Z)- 7 were prepared in 66% overall yield by reaction of β-ionone ((E)-( 1 ) with lithium dimethylcuprate, trapping of the intermediate enolate with benzeneselenenyl bromide and oxidation with H2O2. Analogously, (E/Z)-7-methyl-α-inone ((E/Z)- 12 ) was obtained in 65% yield from α-ionone ((E)- 11 ). 1n, π*- Excitation (λ > 347 nm, pentane) of (E)-7 causes rapid (E/Z)-isomerization and subsequent reaction of (Z)- 7 to 15 (66%). The formation of 15 is explained by twisting of the dienone chromophore due to repulsive interaction of the 7-CH3-group with the CH3-groups of the cyclohexene ring. On the other hand, irradiation λ > 347 nm, Et2O) of (E)- 7 in the presence of acid leads to (Z)- 7 (5%) and to the novel compound 16 (88%). 相似文献
18.
V. V. Khalturina Yu. V. Shklyaev Z. G. Aliev A. N. Maslivets 《Russian Journal of Organic Chemistry》2010,46(4):539-542
5-Arylfuran-2,3-diones react with (Z)-2-[3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]acetamides to give (3E,5Z)-5-(2-aryl-2-oxoethylidene)-3-[3,3-dimethyl-3,4-dihydroisoquinolin-1(2H)-ylidene]-pyrrolidine-2,4-diones. The crystalline and molecular structures of one of the products were determined by X-ray
analysis. 相似文献
19.
Bożena Modzelewska-Banachiewicz Barbara Michalec Teresa Kamińska Liliana Mazur Anna E. Kozioł Jacek Banachiewicz Marzena Ucherek Martyna Kandefer-Szerszeń 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):439-444
Abstract (Z)-3-(3,4-diaryl-1,2,4-triazole-5-yl)prop-2-enoic acid derivatives were obtained in the course of the reaction of N
3-substituted amidrazones with maleic anhydride, and isomerized into the (E) isomers by heating under reflux in acetic acid solution. The molecular structure of the compounds obtained was confirmed
by IR and 1H NMR spectroscopy, and by X-ray crystallography for (2E)-3-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)prop-2-enoic acid. The antiviral and immunomodulating activity of several of the compounds was examined.
Graphical abstract
相似文献
20.
Abstract A facile procedure is presented for the synthesis of (E)-1-(3′-hydroxy-2′-furanyl)-3-(3″-hydroxy-4″-methoxyphenyl)-2- propen-1-one (6). Galactosylisomaltol (1) was condensed with isovanillin (2) under strong alkaline conditions at 25 [ddot]C to form (E)-1-(3′-O-β-D-galactopyranosyloxy-2′-furanyl)-3-(3″- hydroxy-4″-methoxyphenyl)-2-propen-1-one (4). (E)-1-(3′-hydroxy-2′-furanyl)-3-(3″-hydroxy-4″-methoxyphenyl)-2-propen-1-one (6) was obtained by acid hydrolysis of 4 in a 53.9% yield. This hetero-cyclic 2-propen-1-one was characterized on the basis of spectral data (IR and 1H NMR), physicochemical properties, and conversion to a mono-O-acetyl derivative. 相似文献