排序方式: 共有78条查询结果,搜索用时 15 毫秒
1.
Armbruster P Agarwal YK Brüchle W Brügger M Dufour JP Gaggeler H Hessberger FP Hofmann S Lemmertz P Münzenberg G Poppensieker K Reisdorf W Schadel M Schmidt K Schneider JH Schneider WF Sümmerer K Vermeulen D Wirth aG Ghiorso A Gregorich KE Lee D Leino M Moody KJ Seaborg GT Welch RB Wilmarth P Yashita S Frink C Greulich N Herrmann G Hickmann U Hildebrand N Kratz JV Trautman N Fowler MM Hoffman DC Daniels WR von Gunten HR Dornhöfer H 《Physical review letters》1985,54(5):406-409
2.
F. Iskanderani K. M. Sobhi M. Ejaz 《Journal of Radioanalytical and Nuclear Chemistry》1989,132(1):159-169
Normal heptane, xylene, and a 0.01 molar solution of 4-(5-nonyl)pyridine in toluene have been investigated as extractants for selenium(IV) from nitric acid media in potassium iodide. Various parameters affecting the distribution of the element are investigated. Extraction at high aqueous to organic phase volume ratio has been studied, using a liquid-liquid extraction plant with a pulsation column. The results have been employed to measure selenium in spiked water samples. 相似文献
3.
Lan Yu Qi Wang Lu Dai Wei-Ying Li Rong Chen Mian HR Mahmood Hai-Yang Liu Chi-Kwong Chang 《中国化学快报》2013,24(6):447-449
Pseudo-first order reaction rate constants of 5,10,15-tris(pentafluorophenyl)corrole Mn(V)-oxo (F15CMn(V)-oxo),5,15-bis(pentafluorophenyl)-10-(phenyl)corrole Mn(V)-oxo(F10CMn(V)-oxo),5,15- bis(phenyl)-10-(pentafluorophenyl)corrole Mn(V)-oxo(F5CMn(V)-oxo) and 5,10,15-tris(phenyl)corrole Mn(V)-oxo(F0CMn(V)-oxo) with a series of alkene substrates in different solvents were determined by UV-vis spectroscopy.The results indicated that the oxygen atom transfer pathway between Mn(V)-oxo corrole and alkene is solvent-dependent. 相似文献
4.
Abstract
The effect of Ni2+ cation, imidazole, and mixtures of them on the corrosion behavior of carbon steel in 0.5 M H2SO4 solution was studied by using galvanostatic polarization, potentiodynamic anodic polarization, and weight-loss techniques. Ni2+ cation, imidazole, and mixtures of them provide a good protection to carbon steel against pitting corrosion in chloride-containing solutions. The inhibiting solutions were analyzed by using UV–Vis spectrophotometry. The inhibition was explained on the basis of formation of a complex between the two components. The inhibition mechanism was discussed in terms of the results derived from corrosion and UV–Vis spectrophotometric measurements as well as conductometric investigations. 相似文献5.
Hua-Hua Wang Yi-Yu Jiang Mian HR Mahmood Hai-Yang Liu Herman H.Y. Sung Ian D. Williams Chi K. Chang 《中国化学快报》2015,26(5):529-533
Tetrakis(alloxycarbonyl)porphyrin and its β-octafluoro-substituted derivatives were synthesized via Lindsey method and transformed to their zinc complexes.Single crystal X-ray structures of corresponding Zn(Ⅱ) porphyrins revealed that β-octafluorination will give more compactness of porphyrin moieties in the crystal structure owing to the hydrogen bonding interactions involving β-fluorine atoms.An unusual six-coordinated Zn(Ⅱ) was found via intramolecular coordination of oxygen atom of meso-substituents with central Zn(Ⅱ). 相似文献
6.
Lee J. Silverberg Tapas K. Mal Carlos N. Pacheco Megan L. Povelones Madeline F. Malfara Anthony F. Lagalante Mark A. Olsen Hemant P. Yennawar Hany F. Sobhi Kayla R. Baney Robin L. Bozeman Craig S. Eroh Michael J. Fleming Tracy L. Garcia Casey L. Gregory Julia E. Hahn Alyssa M. Hatter Lexi L. Johns Tianna L. Klinger Jennie J. Li Andrew J. Menig Grace C. Muench Melissa E. Ramirez Jordyn Reilly Nicole Sacco Alexandra M. Sheidy Marla M. Stoner Eric N. Thompson Soroush F. Yazdani 《Molecules (Basel, Switzerland)》2021,26(20)
A series of fourteen 2-aryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-phenyl-C-aryl imines with thionicotinic acid, two difficult substrates. The reactions were operationally simple, did not require specialized equipment or anhydrous solvents, could be performed as either two or three component reactions, and gave moderate–good yields as high as 63%. This provides ready access to N-phenyl compounds in this family, which have been generally difficult to prepare. As part of the study, the first crystal structure of neutral thionicotinic acid is also reported, and showed the molecule to be in the form of the thione tautomer. Additionally, the synthesized compounds were tested against T. brucei, the causative agent of Human African Sleeping Sickness. Screening at 50 µM concentration showed that five of the compounds strongly inhibited growth and killed parasites. 相似文献
7.
Sobhi M. Gomha 《Monatshefte für Chemie / Chemical Monthly》2009,32(7):213-220
Abstract
The reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one or its 2-methylthio derivative with hydrazonoyl halides, in the presence of triethylamine, yielded 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The structure of the latter compounds was further confirmed by reaction of 2-mercapto-6,7,8,9-tetrahydro-3H-benzo[4,5]thieno[2,3-d]pyrimidin-4-one with the appropriate active chloromethylenes followed by coupling of the products with benzenediazonium chloride to afford the non-isolable azo-coupling products which converted, in situ, to 6,7,8,9-tetrahydrobenzo[4,5]thieno[2,3-d]-1,2,4-triazolo[4,5-a]pyrimidin-5-ones. The reaction mechanism was proposed and the products were screened for their biological activity. Some of the newly synthesized compounds had a moderate effect against some bacterial and fungal species. 相似文献8.
9.
Isoxazolopyrimidinethione and Isoxazolopyridopyrimidinethione Derivatives: Key Intermediates for Synthesis of Novel Fused Triazoles as Potent 5α‐Reductase Inhibitors and Anti‐Prostate Cancer
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Sobhi M. Gomha Mohamed G. Badry Mohamed M. Abdalla 《Journal of heterocyclic chemistry》2016,53(2):558-565
The arylideneisoxazolone derivative 1 is used for preparation of two different pyrimidinethiones 3 and 5 through interaction with thiourea and thiouracil, respectively. Compounds 3 and 5 were subjected to reaction with different hydrazonyl halides in basic medium to afford different triazolopyrimidines 9a , 9b , 9c , 9d , 9e , 9f , 9g , 9h and 13a , 13b , 13c , 13d , 13e , 13f , the structures were confirmed by their spectral and elemental analysis. All the newly synthesized products were screened against 5α‐reductase. Some of the newly synthesized compounds showed potent 5α‐reductase inhibition activities with good ED50. 相似文献
10.
Successful implementation of ultrasound irradiation for the rapid synthesis of a novel series of 3-[1-(4-substituted-5-(aryldiazenyl)thiazol-2-yl)hydrazono)ethyl]-2H-chromen-2-ones 5a-h, via reactions of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene) thiosemicarbazide (2) and the hydrazonoyl halides 3(4), was demonstrated. Also, a new series of 5-arylidene-2-(2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinyl)thiazol-4(5H)-ones 10a-d were synthesized from reaction of 2 with chloroacetic acid and different aldehydes. Moreover, reaction of 2-cyano-N'-(1-(2-oxo-2H-chromen-3-yl)ethylidene)-acetohydrazide (12) with substituted benzaldehydes gave the respective arylidene derivatives 13a-c under the conditions employed. The structures of the synthesized compounds were assigned based on elemental analyses and spectral data. Also, the cytototoxic activities of the thiazole derivative 5a was evaluated against HaCaT cells (human keratinocytes). It was found that compound 5a possess potent cytotoxic activity. 相似文献