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1.
Peruncheralathan S Khan TA Ila H Junjappa H 《The Journal of organic chemistry》2005,70(24):10030-10035
[reaction: see text] Highly efficient and regioselective synthesis of 1-aryl-3,4-substituted/annulated-5-(methylthio)pyrazoles and 1-aryl-3-(methylthio)-4,5-substituted/annulated pyrazoles has been reported via cyclocondensation of arylhydrazines with either alpha-oxoketene dithioacetals or beta-oxodithioesters. 相似文献
2.
The 1,3-dipolar cycloaddition reaction of 5-nitro-2-furyldiazomethane ( 1 ) with acrylonitrile, acrylamide, methyl acrylate, diethyl fumarate, methyl methacrylate and methyl cinnamate afforded the corresponding 3-substituted pyrazolines. ( 2a-f ). Similarly the pyrazoles ( 3b-d ) were prepared by addition of 1 to acetylenic compounds such as diethyl acetylenedicarboxylate, methyl phenylpropiolate and cyanoacetylene. Reaction of 1 with fumaronitrile and ω-nitro-styrene gave also the corresponding pyrazoles ( 3a and 3e ) instead of the pyrazolines. 3-(5′-Nitro-2′-furyl)-4-phenyl-5-carbomethoxypyrazoline ( 2f ) was oxidized with lead tetraacetate to the corresponding pyrazole ( 3f ), which was different from 3c , an addition product of 1 with methyl phenylpropiolate. 3-(5′-Nitro-2′-furyl)-5-carbamidopyrazoline ( 2b ) was pyrolyzed to the corresponding cyclopropane derivative 4 in low yield. 相似文献
3.
A. E. Ivanova O. G. Khudina Ya. V. Burgart V. I. Saloutin M. A. Kravchenko 《Russian Chemical Bulletin》2011,60(11):2396-2400
Alkylation of polyfluoroalkyl-containing pyrazoles with 4-bromobutyl acetate in acetone in the presence of potassium carbonate leads to a mixture of isomeric 1-(4-acetoxybutyl)-3-fluoroalkyl- and 1-(4-acetoxybutyl)-5-fluoroalkylpyrazoles, which in a number of cases were successfully separated by HPLC. Deacylation in acidic medium with gaseous hydrogen chloride and in basic medium with gaseous ammonia leads to 1-(4-hydroxybutyl)pyrazoles, which manifest moderate tuberculostatic activity. 相似文献
4.
G. V. Bozhenkov G. G. Levkovskaya A. N. Mirskova L. I. Larina 《Chemistry of Heterocyclic Compounds》2005,41(7):854-860
A method has been developed for obtaining 3-alkyl(phenyl)-4(5)-chloro-1-(2,4-dinitrophenyl)pyrazoles from appropriate dinitrophenylhydrazones
of 1-chloro-, 1,2-, and 2,2-dichlorovinyl ketones by heating the latter in polyphosphoric acid. The structure of the pyrazoles
was studied by IR and 1H NMR spectroscopy.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1012–1019, July, 2005. 相似文献
5.
Andrei Shavnya Martha L. Minich Bryson Rast Kristin Lundy DeMello Burton H. Jaynes 《Tetrahedron letters》2005,46(40):6887-6891
Fluoride-mediated nucleophilic substitution reactions of 1-(4-methylsulfonyl (or sulfonamido)-2-pyridyl)-5-chloro-4-cyano pyrazoles with various amines and alcohols occur under mild conditions to provide the 5-alkyl amino and ether pyrazoles in moderate to high yields. 相似文献
6.
Regioselective routes for the synthesis of 1,3-(or 1,5-)diphenyl-4-aryl/heteroaryl-5-(or 3-)(methylthio)pyrazoles via Suzuki cross-coupling of 4-bromo (or 4-iodo)-1,3-(or 1,5-)diphenyl-5-(or 3-)(methylthio)pyrazoles have been reported. 相似文献
7.
Richard Neidlein Danijel Kikelj Walter Kramer 《Journal of heterocyclic chemistry》1989,26(5):1335-1340
2-(Alkoxycarbonylcyanomethylene)-1,3-dioxolanes reacted with hydrazines and hydroxylamine to yield 1-substituted 4-alkoxycarbonyl-5-amino-3-(2′-hydroxyethoxy)pyrazoles and 4-alkoxycarbonyl-5-amino-3-(2′-hydroxyethoxy)isoxazoles respectively. With guanidine and benzamidine 2-substituted (R = NH2, C6H5) 5-cyano-6-(2′-hydroxyethoxy)pyrimidin-4-ones were obtained. Reaction of 2-(cyanomethoxycarbonylmethylene)-1,3-dioxolane with 1,3-diaminopropane afforded 2-(cyanomethoxycarbonylmethylene)-1,3-hexahydro-pyrimidine whereas treatment of the same compound with 4,5-dimethyl-1,2-phenylenediamine gave 2-(cyanomethoxycarbonylmethylene)-5,6-benzimidazoline. The structures of pyrazoles and pyrimidones were assigned on the basis of 1H-{1H} and 13C-{1H}-nOe experiments. 相似文献
8.
Subas M SakyaBryson Rast 《Tetrahedron letters》2003,44(41):7629-7632
Nucleophilic substitution reactions of 1-(4-methylsulfonyl-2-pyridyl)-5-chloro pyrazoles with various substitutions at the 4 position with amine nucleophiles and thiols occur under mild conditions to provide the 5-alkyl amino and thioether pyrazoles in high yields. 相似文献
9.
Galina G. LevkovskayaValentina A. Kobelevskaya Elena V. RudyakovaKhanh Q. Ha Dmitrii O. SamultsevIgor B. Rozentsveig 《Tetrahedron》2011,67(10):1844-1851
Synthesis of hard-to-reach 5-chloro-3-alkenylpyrazoles was developed via heterocyclization of alkyl-, benzyl- or dialkylhydrazines with 1,1-dichloro-4-halo-1-alken-3-ones obtained from haloacyl chlorides and vinylidene chloride. The reaction process includes the formation of intermediate 5-chloro-3-(1-haloalkyl)pyrazoles followed by dehydrohalogenation. 相似文献
10.
Peruncheralathan S Yadav AK Ila H Junjappa H 《The Journal of organic chemistry》2005,70(23):9644-9647
[Reaction: see text]. An efficient highly regioselective protocol for the synthesis of isomeric 1,3-diaryl (or 1-aryl-3-alkyl) and 1,5-diaryl (or 1-aryl-5-alkyl)-5 (or 3)-(N-cycloamino)pyrazoles has been reported by cyclocondensation of common alpha-oxoketene N,S-acetal precursors with arylhydrazines by variation of reaction conditions. 相似文献
11.
I. V. Kostyuchenko G. P. Okonnishnikova E. V. Shulishov Yu. V. Tomilov 《Russian Chemical Bulletin》2004,53(10):2257-2261
3-Cyano- and 3-(alkoxycarbonyl)spiro[2-pyrazoline-5,1’-cyclopropane] and 5-phenylspiro[1-pyrazoline-3,1’-cyclopropane] undergo unusual transformations into 3(5)-substituted 5(3)-(2-hydroperoxyethyl)pyrazoles in the presence of atmospheric oxygen. The conditions for the formation of hydroperoxides (e.g., in oxygen-saturated solutions of spiro[2-pyrazoline-5,1’-cyclopropanes] in CHCl3) and their conversion into (2-hydroxyethyl)pyrazoles or the corresponding nitrates under the action of nitrosating reagents were considered.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2160–2164, October, 2004. 相似文献
12.
2-Hydrazinopyridine reacts with allenic and acetylenic nitriles to give 5-amino-3-alkyl-1-(2-pyridyl)pyrazoles 6 in excellent yields. One of these compounds, 6e has been shown to possess anticonvulsant and anti-electroshock properties. Phenyl propynenitrile also reacts with hydrazinopyridine to give 5-amino-3-phenyl-1-(2-pyridyl)pyrazole ( 11 ) in quantitative yield. 相似文献
13.
G. V. Bozhenkov V. A. Savosik L. I. Larina L. V. Klyba E. R. Zhanchipova A. N. Mirskova G. G. Levkovskaya 《Russian Journal of Organic Chemistry》2008,44(7):1014-1023
2-Chlorovinyl alkyl ketones react with alkylhydrazines to give mixtures of 1-R-3-R′- and 1-R-5-R′-pyrazoles: The 1-R-3-R′-pyrazoles form through the heterocyclization of 2-chlorovinyl ketone alkylhydrazones whereas in the heterocyclization into 1-R-5-R′-pyrazoles N 1-alkyl-N 2-(2-acylvinyl)hydrazines are involved. The regiospecific heterocyclization of 2-chloro-and 2,2-dichlorovinyl ketones with arylhydrazines and also of 2,2-dichloro(bromo)vinyl trifluoromethyl ketones with C alkylhydrazines into pyrazoles and 5-chloro(bromo)-pyrazoles proceeds through a stage of haloenones hydrazones formation. The study of the structure of the obtained 1-alkyl-3(5)-alkylpyrazoles by means of two-dimenaional 1H and 13C NMR spectroscopy and GC-MS method made it possible to assign the proton and carbon signals of isomeric pyrazoles and to establish the diagnostic ions for the pair of 1,3-and 1,5-isomers. 相似文献
14.
The interaction of the sodium salts of 3-(1-adamantyl)-1-hydroxy-1-propen-3-one and 4-(1-adamantyl)-1-hydroxy-1-buten-3-one with hydroxylamine, hydrazine, and guanidine leads to the synthesis of 5-(1-adamantyl)-5-hydroxy- and 5-(1-adamantylmethyl)-5-hydroxy-2-isoxazolines, 3-(1-adamantyl)- and 3-(1-adamantylmethyl)pyrazoles, 3-(1-adamantyl)-2-phenylpyrazole, and 4-(1-adamantyl)-2-amino- and 4-(1-adamantylmethyl)-2-aminopyrimidines. 相似文献
15.
We have obtained 4-alkyl-6-amino-5-cyano-3-methyl(propyl, phenyl)-2H,4H-pyrano[2,3-c]pyrazoles by reaction of 4-alkylmethylene-3-substituted 5-pyrazolones with malononitrile or cyanothioacetamide. We have used X-ray diffraction to study the structure of 6-amino-5-cyano-4-isopropyl(hexyl)-3-phenyl-2H,4H-pyrano[2,3-c]pyrazoles. 相似文献
16.
I. B. Dzvinchuk 《Chemistry of Heterocyclic Compounds》2005,41(3):323-328
Cyanoethyl-, ethyl-, and methylhydrazones of 2-phenacyl-1H-benzimidazole undergo recyclization on condensation with aroyl chlorides or dimethylformamide with the formation of 5-(o-aroyl-aminoanilino)pyrazoles or 1-(5-pyrazolyl)-1H-benzimidazoles. The reaction with aroyl chlorides occurs selectively only with the corresponding cyanoethylhydrazone.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 372–378, March, 2005. 相似文献
17.
A convenient preparative two-stage method was developed for the isomerization of 2-phenacyl-1H-benzimidazole arylhydrazones
to previously unknown 5-(o-aminoanilino)-1-aryl-3-phenylpyrazoles. The transformation scheme includes recyclization during
acylation with trifluoroacetic anhydride leading to the formation of 1-aryl-3-phenyl-5-(o-trifluoroacetylaminoanilino)pyrazoles,
which then undergo hydrazinolysis.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1002–1006, July, 2005. 相似文献
18.
Hassan M. Faid Allah Hassan M. Mokhtar R. Soliman 《Journal of heterocyclic chemistry》1981,18(8):1561-1564
The reaction of 1-benzenesulfonyl-3-ethoxycarbonyl-5-[α-substituted-styryl]pyrazoles (1) with isocyanate and thioisocyanate derivatives yield the corresponding benzenesulfonylurea derivatives ( 2 and 3 ). Bromination of 1 afforded the 4-bromopyrazoles 4 which react with isocyanate derivatives giving 5 that were also obtained by bromination of 2 . Alkaline hydrolysis of the benzensulfonylurea derivatives 2 yield the corresponding pyrazole-3-carboxylic acids 7 . 相似文献
19.
Ahmad Sami Shawali Mosselhi A. Mosselhi Farag M.A. Altablawy Thoraya A. Farghaly Nagla M. Tawfik 《Tetrahedron》2008,64(23):5524-5530
Three series of 3,7-bis(arylazo)-6-methyl-2-phenyl-1H-imidazo-[1,2-b]pyrazoles were prepared starting from N-aryl 2-oxo-2-phenylethanehydrazonoyl bromides and 5-amino-4-arylazo-3-methyl pyrazoles. The acid dissociation constants pK and pK* in both the ground and excited states, respectively, were determined and correlated with the Hammett equation. The results of such correlations together with the spectroscopic data indicated that the title compounds exist predominantly in the 1H-bis(arylazo) form in both ground and excited states. 相似文献
20.
Grotjahn DB Van S Combs D Lev DA Schneider C Rideout M Meyer C Hernandez G Mejorado L 《The Journal of organic chemistry》2002,67(26):9200-9209
Syntheses of pyrazoles featuring a functionalized side chain attached to carbon 3 and varying alkyl and aryl substituents attached to carbon 5 are presented. Installation of R = methyl, isopropyl, tert-butyl, adamantyl, or phenyl groups at C5 is reported here, starting by coupling protected alkynols with acid chlorides RCOCl, forming alkynyl ketones, which are reacted with hydrazine to form the pyrazole nucleus. Alcohol deprotection and conversion to a chloride gave 5-substituted 3-(chloromethyl)- or 3-(2-chloroethyl)pyrazoles. This sequence can be done within 2 d on a 30 g scale in excellent overall yield. Through nucleophilic substitution reactions, the chlorides are useful precursors to other polyfunctional pyrazoles. In the work here, derivatives with side chains LCH(2)- and LCH(2)CH(2)- at C3 (L = thioether or phosphine) were made as ligands. The significance of the ligands made here is that by placing a ligating side chain on a ring carbon (C3), rather than on a ring nitrogen, the ring nitrogen not bound to the metal and its attached proton will be available for hydrogen bonding, depending on the steric environment created by R at C5. 相似文献