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Kalkote Uttam Ramrao Choudhary Anil Ramkumar Natu Arvind Anant Ayyangar Nagaraja Ramanuja 《合成通讯》2013,43(10-11):1129-1135
1-Alkylaminoanthraquinones ( 2 a-f) and 1,4-bisalkylaminoanthraquinones ( 4 a-c) were prepared from aminoanthraquinones ( 1,3 ) by alkylation with alkyl sulphate/alkyl halide in presence of powdered sodium hydroxide, potassium carbonate and phase transfer catalyst. 相似文献
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Khalid Mohammed Khan Ghulam Murtaza MaharviSafdar Hayat Zia-UllahM. Iqbal Choudhary Atta-ur-Rahman 《Tetrahedron》2003,59(29):5549-5554
Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters. 相似文献
54.
Samanta S Ghosh D Mukhopadhyay S Endo A Weakley TJ Chaudhury M 《Inorganic chemistry》2003,42(5):1508-1517
The tridentate dithiocarbazate-based Schiff base ligands H(2)L (S-methyl-3-((5-R-2-hydroxyphenyl)methyl)dithiocarbazate, R = NO(2), L = L(2); R = Br, L = L(3)) react with [VO(acac)(2)] in the presence of imidazole derivatives as coligands to form oxovanadium(IV) and cis-dioxovanadium(V) complexes. With benzimidazole and N-methylimidazole, the products are oxovanadium(IV) complexes, viz. [VOL(3)(BzIm)].0.5CH(3)CN (1a) and [VOL(N-MeIm)(2)] (L = L(3), 1b; L = L(2), 1c), respectively. In both 1a,b, the O and S donor atoms of the tridentate ligand are cis to the terminal oxo group (in the "equatorial" plane) and mutually trans, but the N donor atom is respectively cis and trans to the oxo atom, as revealed from X-ray crystallography. When imidazole or 4-methylimidazole is used as the ancillary ligand, the products obtained are water-soluble cis-dioxovanadium(V) complexes [VO(2)L(R'-ImH)] (L = L(3) and L(2), R' = H and Me, 2a-d). These compounds have zigzag chain structures in the solid state as confirmed by X-ray crystallographic investigations of 2a,d, involving an alternating array of LVO(2)(-) species and the imidazolium counterions held together by Coulombic interactions and strong hydrogen bonding. Complexes 2a-d are stable in water or methanol. In aprotic solvents, viz. CH(3)CN, DMF, or DMSO, however, they undergo photochemical transformation when exposed to visible light. The putative product is a mixed-oxidation divanadium(IV/V) species obtained by photoinduced reduction as established by EPR, electronic spectroscopy, and dynamic (1)H NMR experiments. 相似文献
55.
Choudhary V. Varma H. S. Varma I. K. 《Journal of Thermal Analysis and Calorimetry》1987,32(2):579-593
The effects of EPDM rubber on the crystallization behaviour of isotactic polypropylene (iPP) in the ternary iPP/HDPE/EPDM blends were studied by means of DSC and X-ray diffraction. Analysis of the crystallization exotherm peaks in terms of crystallization nucleation and growth rates and crystallinity revealed variations in the morphology of the iPP component in the blends as a function of the EPDM content. The DSC and X-ray diffraction results showed that the overall crystallinity decreased as the weight percentage of EPDM was increased in the iPP/HDPE blends.The morphology of these blends was studied by scanning electron microscopy, which revealed a random distribution of EPDM throughout the iPP matrix. The size and number of these rubber particles increased with increase of the EPDM weight percentage in the ternary iPP/HDPE/EPDM blends. The probable existence of composite inclusions of EPDM-HDPE in an iPP matrix is suggested.
Zusammenfassung Die Effekte von EPDM-Kautschuk auf das Kristallisationsverhalten von isotaktischem Polypropylen (iPP) in den ternären Gemischen iPP/HDPE/EPDM wurden mittels DSC und Röntgendiffraktometrie untersucht. Die Analyse der exothermen Kristallisationspeaks mit Hinblick auf die Kristallisationskeimbildung und die Geschwindigkeit des Kristallwachstums und die Kristallinität deuten auf morphologische Varianten der iPP-Komponente in den Gemischen in Abhängigkeit vom EPDM-Gehalt hin. Die durch DSC und Röntgendiffraktometrie erhaltenen Ergebnisse zeigen, daß die Kristallinität mit steigendem Gehalt an EPDM in den iPP/HDPE-Gemischen abnimmt. Die Morphologie dieser Gemische wurde durch Scanningelektronenmikroskopie untersucht. Es wurde eine random-Verteilung des EPDM in der iPP-Matrix festgestellt. Größe und Zahl dieser Kautschukpartikel nehmen mit zunehmendem EPDM-Gewichtsanteil in den ternären iPP/HDPE/EPDM-Gemischen zu. Auf die wahrscheinliche Existenz von EPDM/HDPE-Einschlüssen in einer iPP-Matrix wird hingewiesen.
(-) - -. , , , . , --. , . ---. - - .相似文献
56.
Dr. Sourav Sarkar Anushree Shil Suman Maity Dr. Yun Lim Jung Dr. Mingchong Dai Prof. Atanu Acharya Prof. Kyo Han Ahn 《Angewandte Chemie (International ed. in English)》2023,62(43):e202311168
Aryl alcohol-type or phenolic fluorophores offer diverse opportunities for developing bioimaging agents and fluorescence probes. Due to the inherently acidic hydroxyl functionality, phenolic fluorophores provide pH-dependent emission signals. Therefore, except for developing pH probes, the pH-dependent nature of phenolic fluorophores should be considered in bioimaging applications but has been neglected. Here we show that a simple structural remedy converts conventional phenolic fluorophores into pH-resistant derivatives, which also offer “medium-resistant” emission properties. The structural modification involves a single-step introduction of a hydrogen-bonding acceptor such as morpholine nearby the phenolic hydroxyl group, which also leads to emission bathochromic shift, increased Stokes shift, enhanced photo-stability and stronger emission for several dyes. The strategy greatly expands the current fluorophores’ repertoire for reliable bioimaging applications, as demonstrated here with ratiometric imaging of cells and tissues. 相似文献
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Prashansa Sharma Suman Pant Shambhavi Rai Renu Bala Yadav Swapnil Sharma Vivek Dave 《应用有机金属化学》2018,32(3)
This research work was proposed to study the antimicrobial activity of the silver nanocoated fabric with the purpose of producing good dressing and clothing material. We synthesized simple, ecofriendly, cost‐effective and sustainable silver nanoparticles by using the aqueous extract of Allium cepa L. Here, A. cepa L. acts as a good reducing and capping agent that produced stable silver nanoparticles having particle size of range 36 ± 1 to 98 ± 2 nm, Poly dispersiblity index 0.234 ± 0.61 to 1.023 ± 0.33 and Zeta potential ‐12 ± 1.5 mV to ‐26 ± 1.2 mV. The effect of temperature and extract volume used was considered for optimization of synthetic procedure. The nanocoated fabric was characterized for morphological study, size (using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE‐SEM) and zeta‐potential (Zeta Potentiometer). The presence of functional groups were observed by using attenuated total reflection‐Fourier transform infrared (ATR‐FTIR) and Raman spectroscopy. The crystallinity and structural property of the synthesized silver nanoparticles were studied in terms of Powder X‐ray diffraction (PXRD). An IC50 value and zone of inhibition was studied which demonstrate that the silver nanocoated fabric have an excellent antibacterial property against Gram‐negative (Escherichia coli) and Gram‐positive (Staphylococcus aureus) bacteria. Further nanocoated fabric material was washed (with function of time 0, 10, 25, and 50 laundry cycles) and still retained their anti‐bacterial activity towards both strain. Initially there was 52 μg/ml of silver nanoparticles on the cotton fabric but after 50 laundry cycle in 500 ml of distilled water the fabric showed 92% efficiency against gram positive and 90% efficacy toward gram negative bacteria. It was found that 4.16 μg/ml nano particles leached in case of S. Aureus and 5.2 μg/mL silver nanoparticles leached in case of E. coli. Nanocoated fabric material synthesized using green synthesis was found to be economical with good resistance to washing. 相似文献
60.
Dr. Madhu Sheri Dr. Umesh Choudhary Dr. Sunitha Grandhee Prof. Todd Emrick 《Angewandte Chemie (International ed. in English)》2018,57(17):4599-4602
We report a fluoride‐catalyzed deblocking of urethanes as “blocked” isocyanates. Organic and inorganic sources of fluoride ion proved effective for deblocking urethanes and for converting polyurethanes to small molecules. Distinct from conventional deblocking chemistry involving organometallic compounds and high temperatures, the method we describe is metal‐free and operates at or slightly above room temperature. The use of fluorescent blocking agents enabled visual and spectroscopic monitoring of blocking/deblocking reactions, and the selected conditions proved applicable to urethanes containing a variety of blocking groups. The method additionally enabled a one pot deblocking and polymerization with α,ω‐diols. Overall, this deblocking/polymerization strategy offers a convenient and efficient solution to problems that have limited the breadth of applications of polyurethane chemistry. 相似文献