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排序方式: 共有129条查询结果,搜索用时 31 毫秒
81.
Dokuburra Chanti Babu Kankati Ashalatha Chitturi Bhujanga Rao Jon Paul Selvam Jondoss Yenamandra Venkateswarlu 《Helvetica chimica acta》2011,94(12):2215-2220
An efficient and short total synthesis of (?)‐cleistenolide ( 1 ) from D ‐mannitol with an overall yield of 23.6% is described. The chiron approach for the synthesis of (?)‐cleistenolide involves a one‐C‐atom Wittig olefination, a selective allylic triethylsilyl protection, and a Grubbs‐catalyzed ring‐closure‐metathesis (RCM) reaction as the key steps. 相似文献
82.
Various chiral stilbenophanes with small and large rigid cavities have been synthesized. Bis-cyclophanes with a stilbene-bridging unit have also been synthesized. Some of the stilbenophanes form charge transfer complexes with either TCNQ or TCNE. Photoisomerization of the bis-cyclophanes has also been studied. 相似文献
83.
J. Jon Paul Selvam 《Tetrahedron letters》2006,47(15):2507-2509
Zirconyl nitrate was found to be an excellent reagent in the nitration of phenol and substituted phenols to give nitrated phenols. This procedure works efficiently on most of the examples at room temperature yielding nitro derivatives in fair to good yields with high regioselectivity. 相似文献
84.
Bharathiraja Subramaniyan Pallavi Rajaputra Luong Nguyen Mengjie Li Cody J. Peer Jessica Kindrick William D. Figg Sukyung Woo Youngjae You 《Photochemistry and photobiology》2020,96(3):668-679
We demonstrated that a large primary and a small untreated distant breast cancer could be controlled by local treatment with our light-activatable paclitaxel (PTX) prodrug. We hypothesized that the treated tumor would be damaged by the combinational effects of photodynamic therapy (PDT) and locally released PTX and that the distant tumor would be suppressed by systemic antitumor effects. Syngeneic rat breast cancer models (single- and two-tumor models) were established on Fischer 344 rats by subcutaneous injection of MAT B III cells. The rats were injected with PTX prodrug (dose: 1 umole kg−1, i.v.), and tumors were treated with illumination using a 690-nm laser (75 or 140 mW cm−1 for 30 min, cylindrical light diffuser, drug-light interval [DLI] 9 h). Larger tumors (~16 mm) were effectively ablated (100%) without recurrence for >90 days. All cured rats rejected rechallenged tumor for up to 12 months. In the two-tumor model, the treatment of the local large tumor (~16 mm) also cured the untreated tumor (4–6 mm) through adaptive immune activation. This is our first demonstration that local treatment with our PTX prodrug produces systemic antitumor effects. Further investigations are warranted to understand mechanisms and optimal conditions to achieve clinically translatable systemic antitumor effects. 相似文献
85.
86.
Nagarajan Panneer Selvam 《Tetrahedron letters》2006,47(42):7481-7483
A new method for the synthesis of acetamido phenols by a one-pot, three-component Ritter type reaction in moderate to good yields is described. Both electron donating and electron releasing substitution on aromatic rings are tolerated. 相似文献
87.
Subramaniyan Ramasundaram Sun Yoon Kap Jin Kim Cheolmin Park 《Journal of Polymer Science.Polymer Physics》2008,46(20):2173-2187
The role of organically modified silicate (OMS), Lucentite STN on the formation of β‐crystalline phase of poly(vinylidene fluoride) (PVDF) is investigated in the present study. The OMS was solution blended with PVDF and cast on glass slide to form PVDF‐OMS nanocomposites. Solution cast samples were subjected to various thermal treatments including annealing (AC‐AN), melt‐quenching followed by annealing (MQ‐AN), and melt‐slow cooling (MSC). Fourier‐transform infrared spectroscopy (FT‐IR), wide angle X‐ray diffraction (WAXD), and differential scanning calorimetry (DSC) were used to investigate the crystalline structure of thermally treated samples. As a special effort, the combination of in situ thermal FT‐IR, WAXD, and DSC studies was utilized to clearly assess the thermal properties. FT‐IR and WAXD results of MQ‐AN samples revealed the presence of β‐phase of PVDF. Ion‐dipole interaction between the exfoliated clay nanolayers and PVDF was considered as a main factor for the formation of β‐phase. Melt‐crystallization temperature and subsequent melting point were enhanced by the addition of OMS. Solid β‐ to γ‐crystal phase transition was observed from in situ FT‐IR and WAXD curves when the representative MQ‐AN sample was subjected to thermal scanning. Upon heating, β‐phase was found to disappear through transformation to the thermodynamically stable γ‐phase rather than melting directly. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2173–2187, 2008 相似文献
88.
Debasish Jana Tapas Guchhait Vasudevan Subramaniyan Ashok Kumar Ganesan Mani 《Tetrahedron letters》2019,60(46):151247
The Mannich reaction of pyrrole with ethylenediamine dihydrochloride and formaldehyde gave two compounds: N1,N1,N2,N2-tetrakis(pyrrol-2-ylmethyl)ethane-1,2-diamine 1 and 1,3-bis(pyrrol-2-ylmethyl)imidazolidine 2 in poor yields. Conversely, the reaction of pyrrole with propylenediamine dihydrochloride afforded macrocyclic compound 3 containing two pyrrole rings bridged by two dimethylenehexahydropyrimidine moieties in 50% yield. The reaction of 2,5-dimethylpyrrole with methylamine hydrochloride and formaldehyde gave novel bicycle 4 consisting of a dimethyltetrahydro-1,3-diazepine ring fused with a 2,5-dimethylpyrrole ring. The reaction of 2,5-dimethylpyrrole with ammonium chloride gave the tripodal ligand tris(2,5-dimethylpyrrol-3-yl)methylamine 5 in 62% yield. The structures of 2–4 were determined by single crystal X-ray diffraction studies. 相似文献
89.
Ordered mesoporous carbon (OMC) supported gold nanoparticles of size 3–4 nm having uniform dispersion were synthesized by sol‐immobilization method. OMCs such as CMK‐3 and NCCR‐56 with high surface area and uniform pore size were obtained, respectively, using ordered mesoporous silicas such as SBA‐15 and IITM‐56 as hard templates, respectively. The resulting OMC supported monodispersed nano‐gold, i. e., Au/CMK‐3 and Au/NCCR‐56, exhibited excellent performance as mild‐oxidizing catalysts for oxidation of glycerol with high hydrothermal stability. Further, unlike activated carbon supported nano‐gold catalysts (Au/AC), the OMC supported nano‐gold catalysts, i. e., Au/CMK‐3 and Au/NCCR‐56, show no aggregation of active species even after recycling. Thus, in the case of Au/CMK‐3 and Au/NCCR‐56, both the fresh and regenerated catalysts showed excellent performane for the chosen reaction owing to an enhanced textural integrity of the catalysts and that with remarkable selectivity towards glyceric acid. The significance of the OMC supports in maintaining the dispersion of gold nanoparticles is explicit from this study, and that the activity of Au/AC catalyst is considerably decreased (~50 %) upon recycling as a result of agglomeration of the active gold nanoparticles over the disordered amorphous carbon matrix. 相似文献
90.
Mohapatra SK Sahoo B Keune W Selvam P 《Chemical communications (Cambridge, England)》2002,(14):1466-1467
Trivalent iron substituted hexagonal mesoporous aluminophosphate molecular sieve has been synthesized and characterized for the first time, which showed excellent catalytic activity and reusability for the cyclohexane oxidation reaction under mild conditions. 相似文献