- Polysiloxanes-based stationary phases containing methoxy-substituted tetraphenyl-phenyl groups for gas chromotographic separations
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3,4-Di(4-methoxy phenyl)-2,5-diphenyl phenyl grafted polysiloxane (MTP) and 3,4-di(3,4,5-trimethoxy phenyl)-2,5-diphenyl phenyl grafted polysiloxane (TMP) were synthesized and statically coated on fused silica capillary columns. The MTP and TMP columns have efficiencies of almost 3400 (k = 3.74, 0.25 mm i.d.) and 3600 (k = 3.96, 0.25 mm i.d.) plates per m, respectively, which are determined by naphthalene at 120 °C. Both columns exhibited moderate polarity based on the McReynolds constants. The separation of the polyethylene pyrolysis products shows that the maximum operating temperature of the two columns can reach up to 360 °C and 370 °C, respectively. In addition, the solvation parameter indicated that the dipole-induced dipole, H-bond alkaline, and dispersive interactions were the main interactions between the solutes and the stationary phases. The separation performance of the new columns was evaluated by gas chromatography separation of the Grob test mixtures. Several mixtures with π-conjugated structure were also well separated on the new columns. This work demonstrated the promising future of the new type of stationary phases in GC analysis.
- He, Xinxin,Han, Xue,Wang, Huan,Wang, Bing,Wu, Bo
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p. 76514 - 76523
(2016/08/30)
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- Self-supported N-heterocyclic carbenes and their use as organocatalysts
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The study of N-heterocyclic carbenes (NHCs) as organocatalysts has proliferated in recent years, and they have been found to be useful in a variety of reactions. In an attempt to further expand their utility and to study their recyclability, we designed and synthesized a series of self-supported NHCs in which the catalytic carbene groups form part of a densely functionalized polymer backbone, and studied them as organocatalysts. Of the self-Supported NHCs examined, a benzimidazole derived polymer with flexible linkers connecting the catalytic groups was found to be the most efficient organocatalyst in a model benzoin condensation reaction, and thus it was used in a variety of such reactions, including some involving catalyst recycling. Furthermore, it was also used to catalyze a set of redox esterification reactions involving conjugated unsaturated aldehydes. In all of these reactions the catalyst afforded good yield of the desired product and its polymeric nature facilitated product purification.
- Ma, Shuang,Toy, Patrick H.
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- Synthesis of 3,4-bis (3, 4, 5-trimethoxyphenyl) - 2,5-diphenyl-cyclopentadienone method
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The invention discloses a method for synthesizing 3, 4-di(3, 4, 5-trimethoxy phenyl)-2, 5-diphenyl cyclopentadienone. The method comprises the following steps: carrying out condensation reaction on 3, 4, 5-trimethoxy benzaldehyde serving as a raw material
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Paragraph 0065-0067
(2017/03/21)
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- (±)Methanodibenzodiazocine tethered [C-H]δ+ functional site: Study towards benzoin condensation and Baylis-Hillman reactions
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Abstract New heterocyclic ring systems consisting of (±) methanodibenzodiazocine and imidazolium/ benzimidazolium salts were synthesized in very good yield. Subsequently, these halide salts were subjected to the anion exchange reaction with KPF6 to yield the corresponding azolium salts in excellent yield. The possible applications of these newly prepared salts were investigated in homogeneous catalysis. Remarkable changes in the catalytic activity were observed by varying the bulkiness of N-substituent at imidazole. Catalytic activity of these newly prepared salts was tested for the benzoin condensation reaction. Exclusive formation of benzoin products were observed in good yield. Similarly, the dimerization of cyclohexen-1-one to Baylis-Hillman type product, 2-(3-oxocyclohexyl)-2-cyclohexen-1-one was studied. [Figure not available: see fulltext.]
- Sathyanarayana, Arruri,Prabusankar, Ganesan
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p. 821 - 831
(2015/08/06)
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- Design, synthesis, cytotoxic evaluation and tubulin inhibitory activity of 4-aryl-5-(3,4,5-trimethoxyphenyl)-2-alkylthio-1H-imidazole derivatives
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A new series of 4-aryl-5-(3,4,5-trimethoxyphenyl)-2-alkylthio-1H-imidazoles were synthesized and their cytotoxic activities in vitro against four different cell lines (HT-29, MCF-7, NIH-3T3, AGS) were evaluated. Compound 6g bearing 3,4,5-trimethoxyphenyl moiety on ring A and 4-methoxy substituent on ring B displayed potent cytotoxic activity against all cell lines. Flow cytometry analysis and microtubule polymerization assay confirmed that cytotoxic activities of this compound were related to inhibitory effect against microtubules polymerization. Molecular modeling studies revealed that compound 6g could strongly bind to the colchicine binding site of α,β-tubulin through hydrogen bond interactions with Thrα179 and Cysβ241.
- Assadieskandar, Amir,Amini, Mohsen,Ostad, Seyed Nasser,Riazi, Gholam Hossein,Cheraghi-Shavi, Tayebe,Shafiei, Bentolhoda,Shafiee, Abbas
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p. 2703 - 2709
(2013/06/27)
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