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排序方式: 共有398条查询结果,搜索用时 15 毫秒
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In this study, a novel Cu-immobilized ionic liquid (IL)was designed, characterized, and employed as both promoter and solvent in the synthesis of some dihydropyrano[2,3-c]pyrazoles. The synthesized ionic liquid was characterized by 1H NMR, 13C NMR, FTIR, ICP and EDX analysis and showed high catalytic activity to proceed the synthesis of bioactive dihydropyrano[2,3-c]pyrazole derivatives. This method has the advantage of using the IL as a green medium for the synthesize of the products in high to excellent yields within short reaction times. 相似文献
3.
以3-( 4-氟苯基) -1H-吡唑-5-甲酸乙酯为原料,与H2NNH2?H2O发生肼解生成3-( 4-氟苯基) -1H-吡唑-5-甲酰肼,再与CS2环化生成2-巯基噁二唑中间体,最后在巯基上进行烷基化反应合成了一系列新型的2-硫醚-5-吡唑基-1,3,4-噁二唑类化合物,并利用IR、1H NMR、HRMS等波谱技术对目标化合物结构进行了表征。该合成方法具有原料易得,后处理简便,收率较高的优点。 相似文献
4.
Denisa Dumitrescu Sergiu Shova Constantin Draghici Marcel Mirel Popa Florea Dumitrascu 《Molecules (Basel, Switzerland)》2021,26(12)
3-Arylsydnones bearing fluorine and bromine atoms on the benzene ring were synthesized from N-nitroso-2-fluorophenylglycines and characterized by NMR spectroscopy. These were employed further in synthesis of the corresponding 1-(2-fluorophenyl)pyrazoles by 1,3-dipolar cycloaddition reaction with dimethyl acetylenedicarboxylate (DMAD) as activated dipolarophile. The sydnones as reaction intermediates were characterized by single crystal X-ray diffraction analysis showing interesting features such as halogen bonding as an important interaction in modeling the crystal structure. 相似文献
5.
Aurora Molinari Alfonso Oliva Marlene Arismendi Elizabeth Imbarack Cristian Glvez Javier Maldonado Arturo San Feliciano 《Journal of heterocyclic chemistry》2015,52(2):620-622
New fused pyrazolo‐1,4‐naphthoquinones were prepared from the reaction of hydrazines with 6‐(4‐methyl‐3‐pentenyl)‐1,4‐naphthoquinone. The reaction was extended to hydroxylamine to afford the corresponding isoxazolo‐1,4‐napthoquinone compound. 相似文献
6.
Dr. Yongxing Tang Prof. Dr. Haixiang Gao Dr. Damon A. Parrish Prof. Dr. Jean'ne M. Shreeve 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11401-11407
Triazole links and polynitropyrazole rings give rise to compounds with energetic properties. These materials were fully characterized by NMR and infrared spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). In addition, the structures of compounds 5 and 8 were confirmed by single‐crystal X‐ray diffraction analysis. Detonation properties, calculated from heats of formation and experimental densities, thermal stabilities, and impact and friction sensitivities support the potential use of these materials for explosive applications. 相似文献
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Comparative characterization of thermal isomerization rates of 6‐phenyl‐1,5‐diazabicyclo[3.1.0]hexane at convection and microwave heating 下载免费PDF全文
Tatiana A. Kornilova Rafael R. Kostikov Alexander F. Khlebnikov Igor G. Zenkevich 《Journal of Physical Organic Chemistry》2018,31(7)
Rate constants of thermal isomerization of 6‐phenyl‐1,5‐diazabicyclo[3.1.0]hexane into 1‐(benzyl)‐4,5‐dihydro‐1H‐pyrazole at convection and microwave heating in toluene and chlorobenzene (solvents) were determined within the temperature range 90°C to 120°С. These data were used for the calculation of activation parameters of isomerization. It is shown that microwave heating increases the rate constants at the same temperature by a factor of 2 to 2.5 as compared with those using convection heating. The reason is that the effective temperature of microwave heating exceeds that of convection heating by 6°C to 9°С in toluene and by 12°C to 20°С in chlorobenzene as solvent. 相似文献
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Nadia R. Mohamed Gamal A. Elmegeed Mervat M. Abdelhalim Hanaa M. Rady 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):848-856
In the aim of identifying new steroidal cytotoxic agents with potential antiproliferative activity against hepatoma cell lines (Hep-G2), we synthesized modified steroids containing the thiadiazole, pyrazole, or dithiole moiety. Epiandrosterone 1 reacted with carbon disulfide and sodium hydride to furnish α-oxoketene dithio-disodium salt 2. Treatment of 2 with the hydrazonoyl halides 5a–d produced the thiadiazole anellated androstanone 7a–d, respectively. The reaction of 1 with hydrazine hydrate produced the hydrazide adduct 8, which cyclized upon reflux in acetic acid to form the condensed pyrazoloandrostanone derivative 9. Interaction of 8 with carbon disulfide and sodium hydride formed the disodium salt 10, which reacted with ethylchloroacetate to furnish the final adduct, dithioloandrostane derivative, 13. Compounds 7a, 7d, 9, and 13 were examined for their cytotoxicity against a panel of hepatoma cell lines (Hep-G2) using MTT assay. The results provide that, at incubation time 72 h, in DMSO, compound 7d (50 μ mol/mL) showed the most significant cytotoxic effect at P < 0.05. The higher dose (100 μ mol/mL) of compound 7d, at 48 h incubation, reversed the effect causing resistance and the growth rate return to the control level. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献