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1.
Mohamed M. Abdalla Bakr F. Abdel-Wahab Abdel-Galil E. Amr 《Monatshefte für Chemie / Chemical Monthly》2009,60(1):129-137
Abstract
N-(p-substituted phenyl)-4-cyanopyrrolidin-3-ones and their corresponding hydrazines were prepared and used as starting materials
to synthesize heterocyclic candidates as serotonin antagonist and antianexity agents. Condensation of hydrazines with selected
aromatic aldehydes afforded the corresponding Schiff bases. The hydrazines were treated with phenyl isothiocyanate to afford
the corresponding thiosemicarbazides, which were cyclized with ethyl bromoacetate to N-phenylthiazolidinones. The hydrazine was reacted with 1,2,4,5-tetrachlorophthalic anhydride to give the tetrachloroimide
derivative. It was reacted with benzoyl acetonitrile, 2-(bismethylsulfanyl-methylene)malononitrile, 2-ethoxymethylenemalononitrile,
or 2-cyano-3-ethoxyacrylic acid ethyl ester to afford the corresponding pyrazoline derivatives. Schiff bases were obtained
by simple condensation of the hydrazine with different carbonyl compounds. All the compounds were screened for their serotonin
antagonistic and antianexity activities, and they showed high activities compared to buspirone and diazepam as controls.
Graphical abstract
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Kralj D Novak A Dahmann G Groselj U Meden A Svete J 《Journal of combinatorial chemistry》2008,10(5):664-670
Two variations of enaminone-based parallel solution-phase synthesis of 1-substituted 4-(2-aminoethyl)-1 H-pyrazol-5-ols 8 and their NH-tautomers 8' were developed. The synthetic strategy comprises a two step preparation of the N-protected alpha-enamino lactams 3a and 3b from 2-pyrrolidinone (1), "ring switching" transformation of 3a, b with monosubstituted hydrazines 4a-u, and acidolytic removal of the N-protecting group. In order to ensure a clean and fast conversion, reactions of Cbz-enaminone 3a with hydrazines 4a-k were carried out under microwave irradiation to afford the "ring-switched" intermediates 7a-k. Deprotection of 7a-k with HBr-AcOH at 50 degrees C gave a library of 11 analytically pure 4-(2-aminoethyl)-1 H-pyrazol-5-ols (di)hydrobromides 8/ 8'a-k in 16-75% yields over two steps. The other reagent, Boc-enaminone 3b, was more reactive and ring switching transformations with hydrazines 4b, d, k proceeded smoothly and cleanly under conventional heating. Finally, a parallel one-pot transformation of the Boc-enaminone 3b with hydrazines 4a-u followed by subsequent deprotection of the intermediates 9a-u with HCl-EtOAc furnished a library of 21 analytically pure 4-(2-aminoethyl)-1 H-pyrazol-5-ols (di)hydrochlorides 8/ 8'a-u in 40-100% yields. 相似文献
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The triphenylphosphine mediated reactions of electron-deficient carbon-carbon triple bonds with 3-acetylcoumarins in dichloromethane afford functionalized 3-acetyl-4-(substituted ethylenyl)coumarins. Also, triphenylphosphine-catalyzed three-component cascade annulation reactions of 3-acetylcoumarins, activated acetylenic compounds, and hydrazines or amines provide a straightforward access to 3,5-dihydro-2H-chromeno[3,4-c]pyridine-1,2-dicarboxylates. In these strategies, the main step to the target products is proton transfer process. All products were obtained in good to high yields. 相似文献
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The preparation of several ethyl 3-(1,2-dialkylhydrazino)propanoates (III) by the reaction of 1,2-dialkylhydrazines with acrylates is described. Compound III is accompanied by small amounts of the bis addition products (V) in the reactions of ethyl acrylate with a few of the hydrazines. Cyclization of III to 1,2-dialkyl-3-pyrazolidinones (IV) was achieved with sodium methoxide. 1,2-Dialkyl-5-methyl-3-pyrazolidinones were obtained directly from 1,2-dialkylhydrazines and ethyl crotonate. A procedure for the preparation of 1,2-di-(2-ethoxycarbonylethyl)hydrazines is also given. 相似文献
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A series of α-[3-alkyl-3,4-dihydro-2-oxo-2H-1,3-benzoxazin-4-yl]-β-keto ester derivatives 1 (Table I) were synthesized by the condensation of 3-alkyl-3,4-dihydro-4-hydroxy-2H-1,3-benzoxazine-2-ones 3 (2) with β-keto esters 4 in the presence of traces of mineral acids under azeotropic conditions. Condensation of 1 with hydrazines 5 gave pyrazolone derivatives 2 (Table II). Condensation of β-diketone derivatives 6 with hydrazines 5 and with 1,2-benzenediamine ( 8 ) resulted in the formation of pyrazoles ( 7a-c ) and diazepine derivatives 12 (Table III) and 13 , respectively. 相似文献
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Borkin DA Puscau M Carlson A Solan A Wheeler KA Török B Dembinski R 《Organic & biomolecular chemistry》2012,10(23):4505-4508
5-Exo-dig cyclocondensation of alk-3-yn-1-ones with hydrazines, in the presence of montmorillonite K-10, provides an effective method with a high atom economy for the synthesis of diversely 1,3,5-trisubstituted pyrazoles. The microwave-accelerated reaction proceeds in the absence of solvent and leads to 5-benzyl substituted pyrazoles with good yields (72-91%). The regiochemistry of the process was confirmed by the X-ray crystallographic structure determination of 1-(2-fluorophenyl)-5-(4-methylbenzyl)-3-phenyl-1H-pyrazole. 相似文献
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Durgeswari L. K. Ganta Ravi Kumar Murthy Y. L. N. 《Russian Journal of Organic Chemistry》2021,57(9):1552-1558
Russian Journal of Organic Chemistry - A series of novel 1-(4-aryl-1,3-thiazol-2-yl)-2-{[1-(3-methylbut-2-en-1-yl)-1H-indol-3-yl]methylidene}hydrazines were synthesized and properly... 相似文献
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Ragnarsson U Grehn L Koppel J Loog O Tsubrik O Bredikhin A Mäeorg U Koppel I 《The Journal of organic chemistry》2005,70(15):5916-5921
The pK(a) values in DMSO for 22 di- and triprotected hydrazine NH acids and two monosubstituted hydrazines have been determined using potentiometric titration. The results of density functional theory calculations at the B3LYP/6-311+G level of gas-phase acidities of a representative selection of mono-, di-, and trisubstituted hydrazines are compared with both the relevant published and novel experimental titration data. In the course of this work, a rough estimation of the pK(a) value of hydrazine in DMSO (ca. 38.0) has been deduced. For typical triprotected compounds of this kind containing moderately electron-withdrawing carbamate and imidodicarbonate or arenesulfonylcarbamate functions the pK(a) values fall in the range 15.1-17.3, whereas for N,N'-diprotected hydrazines with a carbamate and an aromatic sulfonyl group the corresponding values are 12.7-14.5. Several of these triprotected derivatives have recently been applied preparatively in stepwise synthesis of substituted hydrazines using alkyl halides as electrophiles in the presence of a phase transfer catalyst, and a few of them, with varying success, have been examined in model experiments with benzyl alcohol, triphenylphosphine, and diethyl azodicarboxylate in the Mitsunobu reaction. The dependence of the reactivity on the intrinsic acidity of the hydrazines in this reaction is highlighted. Furthermore, the regioselective alkylation of an N,N'-diprotected hydrazine can be rationalized on the basis of the presented data. 相似文献
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3-(2-Arninophenyl)indazoles 2 were prepared by the reaction of the o-fluorobenzophenones 1 with hydrazines. These indazoles were converted to the tetracyclic title compounds by conventional methods. 相似文献
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Hikari Morita Kazuho Harada Yoshihisa Okamoto Kaname Takagi 《Journal of heterocyclic chemistry》1999,36(3):767-770
3-Chloro- and 3-bromo-4-methoxycoumarins 1a,b were readily transformed into 4-halo-5-(2-hydroxyphenyl)-3-oxo-2,3-dihydropyrazoles 2a,b with hydrazines. In the reaction of 1a,b with excess hydrazine and phenylhydrazine in boiling ethanol, unexpected 4-hydrazono-3-(2-hydroxyphenyl)-2-pyrazolin-5-ones 3 , 5 were obtained. The structure of 3 was determined by X-ray diffraction analysis. 相似文献
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Chornous V. A. Mel'nichenko N. V. Bratenko M. K. Vovk M. V. 《Russian Journal of Organic Chemistry》2002,38(3):405-410
3-Aryl(heteryl)-1-phenyl-4-pyrazolecarbonyl isothiocyanates were synthesized by treatment of 3-aryl(heteryl)-1-phenyl-4-pyrazolecarbonyl chlorides with lead, sodium, or ammonium thiocyanate. Their reactions with amines, hydrazines, and acylhydrazines gave the corresponding thioureas and thiosemi- carbazides. 相似文献
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S. A. Konovalova A. P. Avdeenko S. A. Goncharova V. V. D’yakonenko S. V. Shishkina 《Russian Journal of Organic Chemistry》2016,52(5):644-649
Reaction direction of N-sulfonyl derivatives of 1,4-benzoquinone monoimine with substituted hydrazines depends on the redox potential of the quinone imine and on the basicity of the hydrazine. Aryl (alkyl)hydrazines of high basicity favor the reduction of quinone monoimine. In reactions with less basic aroylhydrazones N'-(4-oxocyclohexa-2,5-dienylidene)aroylhydrazides were obtained only from the alkylsubstituted in the quinoid ring N-sulfonyl derivatives possessing a lower redox potential. 相似文献
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Moballigh Ahmed 《Tetrahedron letters》2004,45(4):869-873
Reaction of aliphatic olefins with synthesis gas and hydrazines in the presence of rhodium phosphine catalysts leads directly to the corresponding hydrazones. Applying Iphos as ligand good to excellent yields and high chemo- and regioselectivities were obtained in toluene under mild conditions. In case of aromatic hydrazines in situ Fischer indole synthesis can be combined with the new hydrazone preparation to give substituted indoles directly from olefins. 相似文献
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Reactions of 5,8-dichloro-2,3-dicyanoquinoxaline with primary amines and hydrazines under different experimental conditions were investigated. Alkylamines provided novel 3-alkylamino-5,8-dichloro-2-cyanoquinoxalines and N-alkyl-(5,8-dichloro-3-alkylamino-2-quinoxalinyl)carboxamidines in high yields. Alkylhydrazines and lithium arylhydrazinides gave previously unattainable 1-alkyl-3-amino-5,8-dichloroflavazoles and 3-amino-1-aryl-5,8-dichloroflavazoles in good to near quantitative yields whose molecular structure was confirmed by X-ray crystallography of 3-[N,N-bis(4-chlorobenzoyl)amino]-5,8-dichloro-1-phenylflavazole. Reaction with hydrazine gave 5,8-dichloro-3-hydrazino-2-quinoxalinylcarboxamidrazone quantitatively, which was converted to the parent compound of this class of flavazoles, 3-amino-5,8-dichloroflavazole, in high yield by a pyrolytic process involving loss of hydrazine. 相似文献
19.
S. A. Giller A. V. Eremeev I. Ya. Kalvin'sh É. É. Liepin'sh D. A. Tikhomirov 《Chemistry of Heterocyclic Compounds》1975,11(2):212-214
A method was developed for the synthesis of 3(5)-aminopyrazole, 1-phenyl-5-aminopyrazole, and 1-ethyl-3-aminopyrazole by reaction of α-chloroacrylonitrile with the appropriate hydrazines. The corresponding addition products -3-(2,2-dimethylhydrazino)- and 3-(2-phenylhydrazino)-2-chloropropionitriles — were isolated in the case of 1,1-dimethylhydrazine and phenylhydrazine. 相似文献
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Viktor O. Iaroshenko Friedrich ErbenSatenik Mkrtchyan Ani Hakobyan Marcelo Vilches-HerreraSergii Dudkin Alina Bunescu Alexander VillingerVyacheslav Ya. Sosnovskikh Peter Langer 《Tetrahedron》2011,67(41):7946-7955
4-Chloro-3-(trifluoroacetyl)- and 4-chloro-3-(methoxalyl)coumarins react with electron-rich aminoheterocycles, dimethyl 1,3-acetonedicarboxylate, hydrazines, alkyl thioglycolates, and methyl sarcosinate to give a variety of 3,4-heteroannulated coumarins. The starting materials were prepared by the reaction of 4-hydroxycoumarin with trifluoroacetic anhydride and methyl 2-chloro-2-oxoacetate in the presence of trimethylsilylchloride. An NMR study and X-ray crystallographic analysis are reported. 相似文献