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Ahmed M. Hussein 《Journal of Saudi Chemical Society》2010,14(1):61-68
An easy and efficient route for the synthesis of some tetrazolo[1,5-a]-, pyrazolo[1,5-a]- and pyrimido[1,6-a] pyrimidine derivatives was described through the reaction of sodium salts of formyl ketones with 5-aminotetrazole, 5-aminopyrazole derivatives and 6-aminothiouracil, respectively. The antimicrobial screening of some derivatives of the prepared compounds has been achieved, and it exhibited a moderate activity against the tested microorganisms. 相似文献
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《Journal of Molecular Structure》1997,415(3):285-292
4,5,6,7-tetrahydro-5,7-dioxo-[1,2,4]triazolo-[1,5-a]pyrimidine (H2tpO2) has been synthesized as well as its monosodic salt, the crystal structure of the latter having been determined by X-ray diffraction. H2tpO2 possesses a very acidic active methylene group, as indicated by its dissociation constant (pKal = 2.9). One of the hydrogen atoms in this group could then migrate to a basic position of the molecule, generating a zwitterionic or enolic form, nevertheless molecular orbital calculations point to the tautomer that keeps the CH2 group as the most stable one.The anionic form HtpO−2 is generated by the elimination of one of the protons at C6 rather than that attached to N4, as indicated by NMR data and also by the X-ray diffraction data of Na(HtpO2)·2H2O, this being consistent with theoretical calculations. The role of the molecular orbitals of HtpO−2 in possible coordination to metal ions is discussed. 相似文献
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V. D. Orlov Kh. Kiroga N. N. Kolos S. M. Desenko 《Chemistry of Heterocyclic Compounds》1988,24(7):791-794
We have studied the reaction of 5-amino-3-phenylpyrazole with chalcones which takes place with the formation of arylsubstituted forms of dihydropyrazolo[1,5-a]pyrimidine and have discussed a possible mechanism for the reaction. Dehydrogenation of the compounds prepared has been effected using N-bromosucciniimide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 962–965, July, 1988. 相似文献
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REN Xue-Ling WU Chao GAO Ying ZOU Xiao-Mao YANG Hua-Zheng② 《结构化学》2004,23(3):267-269
1 INTRODUCTION The pyrazolo[1,5-a]pyrimidines are the active compositions in many pesticides and medicines. A new class of KDR (tyrosine kinase VEGFR-2) ki- nase inhibitors is discovered and found to have affi- nity for the human CRF-1 (Corticotrophin re… 相似文献
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The title compound, C16H14N4S, has been synthesized by the reaction of pentane-2,4-dione with 5-amino-3-benzylthio-4-cyano-l-H-pyrazole in ethanol, and its crystal structure was determined by X-ray diffraction method. The crystal is of monoclinic, space group P21/n with a=8.699(3), b=23.139(9), c=7.536(3) A, β= 92.400(8)°, V= 1515.5(10) A3, Z=4,Mr=294037, Dc= 1.290 g/cm3, λ=0.71073 A,μ(MoKo)=0.212 mm-1 and F(000)=616. The structure was refined to R=0.0533 and wR=0.1141 for 2672 unique reflections with Rint= 0.06.distance of 3.875 A and the angle of 164.8°. 相似文献
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Fused pyrazolopyrimidines. I. Pyrazolo[4,3-e]-v-triazolo[1,5-a]pyrimidine. A new heterocyclic system
Misbahul Ain Khan Antonio Carlos Carreira Freitas 《Journal of heterocyclic chemistry》1980,17(7):1603-1604
5-Azido-4-cyano-1-phenylpyrazole reacts with benzylcyanide in the presence of sodium methoxide to give the title ring system. 相似文献
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Mikio Hori Kiyomi Tanaka Tadashi Kataoka Hiroshi Shimizu Eiji Imai Kazuhiko Kimura Yoshinobu Hashimoto 《Tetrahedron letters》1985,26(10):1321-1322
5,7-Dimethyl[1,2,4]triazolo[1,5-a]pyrimidinio-3-phenacylide () generated by the reaction of an iminium salt () with 1 eq. of triethylamine, underwent a new thermal ring cleavage of the triazole moiety to give the pyrimidine derivative. However reaction of with 2 eq. of triethylamine afforded the 2-iminooxazoline derivative. The iminooxazoline reacted with nucleophiles such as alcohols or amines to give imidazoles. 相似文献
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Mohamed A. Salem Mohamed H. Helal Moustafa A. Gouda Hala H. Abd EL-Gawad Marwa A. M. Shehab Abeer El-Khalafawy 《合成通讯》2019,49(14):1750-1776
The development of new synthetic routes towards pyrazolo[1,5-a]pyrimidines for their biological and medicinal exploration is an attractive area for researchers. This review focuses on various synthetic routes developed in the last decade for the synthesis of differently substituted pyrazolo[1,5-a]pyrimidines by a broad range of organic reactions by means of 5-aminopyrazole as a precursor. 相似文献
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The syntheses of some diheterocyclic compounds from 2-thioacetohydrazide- 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (1) are described. Compound 1 can be converted into triazoles, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles. The structures of the intermediates and the target compounds were confirmed by (1)H-NMR, MS and elemental analyses. 相似文献
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Molecular and crystal structure of 5,7-diphenyl-7-methyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine
O. V. Shishkin N. V. Getmansky S. M. Desenko V. D. Orlov S. V. Lindeman Yu. T. Struchkov 《Russian Chemical Bulletin》1993,42(11):1827-1829
The molecular and crystal structures of 5,7-diphenyl-7-methyi-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine have been studied by X-ray structural methods. The crystal is monoclinic,a=16.112(3),b=13.489(3),c=14.480(3)Å, =101.62(2)°,Z=8, space groupC2/c,R=0.071. The presence of short intermolecular contacts indicates considerable steric strain in the molecule. The dihydropyrimidine ring exists in an unevenly planar boat conformation. Increasing the steric strain of the dihydrocycle leads to a twisted conformation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1912–1914, November, 1993. 相似文献
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9-Methyl-di-s-triazolo[4,3-a:4,3-c]pyrimidine and 9-methyl-s-triazolo[4,3-c]tetrazolo[1,5-a]pyrimidine have been synthetized from 4-hydrazino-7-methyl-s-triazolo[4,3-c]pyrimidine. Structural assignments based on nmr, ir and chemical manipulations are discussed. 相似文献
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《Polyhedron》1986,5(9):1405-1411
Copper(II) coordination compounds of several CuA2 salts (A = PF6, BF4, ClO4, CF3SO3 or NO3) with 5,7-dimethyl[1,2,4]triazolo[1,5-a]pyrimidine (dmtp) as a ligand have been studied. The crystal structure of [Cu(dmtp)4(H2O)2](PF6)2 is described. This compound is monoclinic, space group P21/c, a = 11.826(2) Å, b = 9.463(2) Å, c = 17.673(3) Å, β = 97.50(1)°, Z = 2, dcalc. = 1.66 Mg m−3, and has been refined to a final discrepancy factor (R) of 0.0382 based on 2316 reflections. The structure consists of PF−6 anions and centrosymmetric mononuclear [Cu(dmtp)4(H2O)2]2+ cations, Cu2+ being coordinated by four equatorial N(3)-bonded dmtp molecules with CuN = 2.019 and 2.050 Å, and by two axial water molecules with CuO = 2.650 Å. The water molecules form intramolecular hydrogen bonds with the dmtp N(4) atoms. 相似文献
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A. M. Hussein S. M. Sherif A. A. Atalla 《Monatshefte für Chemie / Chemical Monthly》1996,127(11):1153-1160
Summary Condensation of cyano acid hydrazide1 with cyclopentanone in refluxing ethanolic piperidine yields hydrazone2. With mixtures of aliphatic aldehydes and different active methylene reagents,2 reacts to 1,2,4-triazolo[1,5-a]pyridines (8a–f). Compound2 also reacts with arylidenes9a–g to give triazolopyridines10a–g. Reaction of2 with aromatic aldehydes affords compounds13a–c. Diazotation of2 with aryldiazonium chloride in ethanol at 0 °C leads to the azo adducts15a–d. The thieno-1,2,4-triazolopyridine16 is obtained by reaction of8a with elementary sulfur.16 undergoes cycloaddition with -nitrostyrene, maleic anhydride, N-arylmalemide, and acrylonitrile yielding the isoquinolines21–24. All new compounds have been characterized by their IR,1H NMR, and mass spectra.
Ein neuer Syntheseweg für 1,2,4-Triazolo[1,5-a]pyridine und 1,2,4-Triazolo[1,5-a]isochinoline
Zusammenfassung Kondensation des Cyanohydrazids1 mit Cyclopentanon in ethanolischem Piperidin bei Rückflußtemperatur ergibt das Hydrazon2. Mit Gemischen aus aliphatischen Aldehyden und verschiedenen Verbindungen mit aktiven Methylengruppen reagiert2 zu 1,2,4-Triazolo[1,5-a]pyridinen (8a–f). Verbindung2 reagiert außerdem mit den Arylidenen9a–g zu den Triazolopyridinen10a–g. Umsetzung von2 mit aromatischen Aldehyden führt zu den Verbindungen13a–c. Diazotierung von2 mit Aryldiazoniumchloriden in Ethanol bei 0°C ergibt die Azoaddukte15a–d. Das Thieno-1,2,4-triazolylpyridin16 erhält man durch Reaktion von8a mit elementarem Schwefel.16 geht it -Nitrostyrol, Maleinsäureanhydrid, N-Arylmaleimid und Acrylnitril eine Cycloaddition zu den Isochinolinen21–24 ein. Alle neuen Verbindungen wurden durch ihre IR-,1H-NMR- und Massenspektren charakterisiert.相似文献