20357-25-9Relevant academic research and scientific papers
Highly Efficient Supramolecular Catalysis by Endowing the Reaction Intermediate with Adaptive Reactivity
Jiao, Yang,Tang, Bohan,Zhang, Yucheng,Xu, Jiang-Fei,Wang, Zhiqiang,Zhang, Xi
, p. 6077 - 6081 (2018)
A new strategy of highly efficient supramolecular catalysis is developed by endowing the reaction intermediate with adaptive reactivity. The supramolecular catalyst, prepared by host–guest complexation between 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and cucurbit[7]uril (CB[7]), was used for biphasic oxidation of alcohols. Cationic TEMPO+, the key intermediate, was stabilized by the electrostatic effect of CB[7] in aqueous phase, thus promoting the formation of TEMPO+ and inhibiting side reactions. Moreover, through the migration into the organic phase, TEMPO+ was separated from CB[7] and recovered the high reactivity to drive a fast oxidation of substrates. The adaptive reactivity of TEMPO+ induced an integral optimization of the catalytic cycle and greatly improved the conversion of the reaction. This work highlights the unique advantages of dynamic noncovalent interactions on modulating the activity of reaction intermediates, which may open new horizons for supramolecular catalysis.
Upconverting-nanoparticle-assisted photochemistry induced by low-intensity near-infrared light: How low can we go?
Chen, Zhijun,Sun, Wen,Butt, Hans-Jürgen,Wu, Si
, p. 9165 - 9170 (2015)
Upconverting nanoparticles (UCNPs) convert near-infrared (NIR) light into UV or visible light that can trigger photoreactions of photosensitive compounds. In this paper, we demonstrate how to reduce the intensity of NIR light for UCNP-assisted photochemistry. We synthesized two types of UCNPs with different emission bands and five photosensitive compounds with different absorption bands. A λ=974 nm laser was used to induce photoreactions in all of the investigated photosensitive compounds in the presence of the UCNPs. The excitation thresholds of the photoreactions induced by λ=974 nm light were measured. The lowest threshold was 0.5 W cm-2, which is lower than the maximum permissible exposure of skin (0.726 W cm-2). We demonstrate that low-intensity NIR light can induce photoreactions after passing through a piece of tissue without damaging the tissue. Our results indicate that the threshold for UCNP- assisted photochemistry can be reduced by using highly photosensitive compounds that absorb upconverted visible light. Low excitation intensity in UCNP-assisted photochemistry is important for biomedical applications because it minimizes the overheating problems of NIR light and causes less photodamage to biomaterials. Up, up, and away: Upconverting-nanoparticle (UCNP)-assisted photochemistry can be triggered by low-intensity (0.5 W cm-2) near-infrared (NIR) light when highly photosensitive compounds that absorb upconverted visible light are used (see figure). Low excitation intensity in UCNP-assisted photochemistry is important in biomedical applications because it minimizes the overheating problems of NIR light and causes less photodamage to biomaterials.
Polymer-supported IBX-amide reagents: Significant role of spacer and additive in alcohol oxidation
Chung, Woo-Jae,Kim, Duk-Ki,Lee, Yoon-Sik
, p. 2175 - 2178 (2005)
We found that the spacer and additive play a significant role in the oxidation of alkyl alcohols using polymer-supported IBX-amide reagents. The introduction of the spacer between the polymer support and IBX-amide group improved the initial conversion rate (up to 60% conversion). Furthermore, various alcohol compounds, when reacted with IBX-amide resin in the presence of BF3·OEt2, were effectively converted into the corresponding aldehydes or ketones within 5-30 minutes in high purities (>94%) at room temperature. Georg Thieme Verlag Stuttgart.
Synthesis of Azepino[1,2-a]indole-10-amines via [6+1] Annulation of Ynenitriles with Reformatsky Reagent
Iioka, Ryoya,Yorozu, Kohei,Sakai, Yoko,Kawai, Rika,Hatae, Noriyuki,Takashima, Katsuki,Tanabe, Genzoh,Wasada, Hiroaki,Yoshimatsu, Mitsuhiro
, p. 1553 - 1558 (2021/02/26)
Lewis acid-catalyzed [6+1] annulation reactions of 2-cyano-1-propargyl- and 2-alkynyl-1-cyanomethyl-indoles with Reformatsky reagent are described. 8-Aryl, 8-alkyl-, 8-hetaryl-, 9-aryl, and 9-alkyl-azepino[1,2-a]indole amines were obtained through a 7-endo-mode cyclization of the β-aminoacrylate intermediates. The antiproliferative activity of the azepino[1,2-a]indoles analogs against the HCT-116 cells were also examined.
Non-alkylator anti-glioblastoma agents induced cell cycle G2/M arrest and apoptosis: Design, in silico physicochemical and SAR studies of 2-aminoquinoline-3-carboxamides
Gu, Xiangyu,Liu, Jianwen,Ni, Xintong,Qi, Yingxue,Qian, Xuhong,Shao, Xusheng,Xu, Xiaoyong,Yuan, Pengtao
supporting information, (2021/09/22)
Malignant gliomas are the most common brain tumors, with generally dismal prognosis, early clinical deterioration and high mortality. Recently, 2-aminoquinoline scaffold derivatives have shown pronounced activity in central nervous system disorders. We herein reported a series of 2-aminoquinoline-3-carboxamides as novel non-alkylator anti-glioblastoma agents. The synthesized compounds showed comparable activity to cisplatin against glioblastoma cell line U87 MG in vitro. Among them, we found that 6a displayed good inhibitory activity against A172 and U118 MG glioblastoma cell lines and induced cell cycle arrest in the G2/M phase and apoptosis in U87 MG by flow cytometry analysis. Additionally, 6a displayed low cytotoxicity to several normal human cell lines. In silico study showed 6a had promising physicochemical properties and was predicted to cross the blood–brain barrier. Moreover, preliminary structure–activity relationships are also investigated, shedding light on further modifications towards more potent agents on this series of compounds. Our results suggest this compound has a promising potential as an anti-glioblastoma agent with a differential effect between tumor and non-malignant cells.
Buchwald-Hartwig versus Microwave-Assisted Amination of Chloroquinolines: En Route to the Pyoverdin Chromophore
Altevogt, Luca,Baro, Angelika,Bilitewski, Ursula,Freund, Marcel,Laschat, Sabine,Lin, Yulin,Rudolf, Richard,Seubert, Philipp
supporting information, p. 1177 - 1181 (2020/07/20)
The reaction of 2-chloro-6,7-dimethoxy-3-nitroquinoline with a series of amines and aminoalkanoates under basic microwave-mediated conditions and under Buchwald-Hartwig amination conditions is reported. The microwave irradiation favored the reaction with amines, resulting in yields of up to 80percent, whereas amino acid functionalization gave yields comparable to those of Buchwald-Hartwig amination. tert-Butyl (2 R)-4-[(6,7-dimethoxy-3-nitroquinolin-2-yl)amino]-2-hydroxybutanoate was successfully cyclized to the pyoverdin chromophore, a subunit of siderophores.
A preparation method of gefitinib (by machine translation)
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Paragraph 0092-0094, (2019/05/16)
The present invention relates to organic chemical and medical technology field, in particular relates to a preparation method of gefitinib. The present invention provides a preparation method of gefitinib, obtained by formula I compounds, the formula I compound preparation method comprises the following steps: nitration reaction, oxidation reaction, selective demethylation reaction, reduction reaction, a cyclization reaction, phenolic hydroxyl acetylation reaction. The present invention provides a preparation method can at the same time reducing the cost, it is easy for the refined purification, easy preparation and control of related impurities, the overall preparation process routes are greatly optimized, is suitable for industrial scale production. (by machine translation)
Iodine(III)-Catalyzed Electrophilic Nitration of Phenols via Non-Br?nsted Acidic NO2+ Generation
Juárez-Ornelas, Kevin A.,Jiménez-Halla, J. Oscar C.,Kato, Terumasa,Solorio-Alvarado, César R.,Maruoka, Keiji
supporting information, p. 1315 - 1319 (2019/03/07)
The first catalytic procedure for the electrophilic nitration of phenols was developed using iodosylbenzene as an organocatalyst based on iodine(III) and aluminum nitrate as a nitro group source. This atom-economic protocol occurs under mild, non-Br?nsted acidic and open-flask reaction conditions with a broad functional-group tolerance including several heterocycles. Density functional theory (DFT) calculations at the (SMD:MeCN)Mo8-HX/(LANLo8+f,6-311+G) level indicated that the reaction proceeds through a cationic pathway that efficiently generates the NO2+ ion, which is the nitrating species under neutral conditions.
A 3, 4 - dihydro -7 - methoxy -4 - [...] -6 - ethoxylate ester preparation method (by machine translation)
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Paragraph 0067-0069, (2019/05/16)
The present invention relates to organic chemical and medical technology field, in particular to a 3, 4 - dihydro - 7 - methoxy - 4 - [...] - 6 - ethoxylate ester preparation method. The present invention provides a gefitinib 3, 4 - dihydro - 7 - methoxy - 4 - [...] - 6 - ethoxylate ester preparation method comprises the following steps: nitration reaction, oxidation reaction, selective demethylation reaction, reduction reaction, a cyclization reaction, phenolic hydroxyl acetylation reaction. Preparation method provided by the invention can at the same time reducing the cost, it is easy for the refined purification, easy preparation and control of related impurities, the overall preparation process routes are greatly optimized, is suitable for industrial scale production. (by machine translation)
Synthesis and photochemical studies of 2-nitrobenzyl-caged N-hydroxysulfonamides
Zhou, Yang,Bharadwaj, Vinay,Rahman, Mohammad S.,Sampson, Paul,Brasch, Nicola E.,Seed, Alexander J.
, (2019/09/09)
Recently, N-hydroxysulfonamides (RSO2NHOH) caged by photolabile protecting groups have attracted significant interest as potential photoactive nitroxyl (HNO) donors. The selectivity of the desired HNO generation pathway from photocaged N-hydroxysulfonamides versus a competing pathway involving O-N bond cleavage is dependent on the specific photodeprotection mechanism of the phototrigger. We present a new class of photocaged N-hydroxysulfonamides incorporating the well-established o-nitrobenzyl photoprotecting group, including a derivative incorporating an additional carbonate linker. Photodecomposition of o-NO2Bn-ON(H)SO2CF3 and the corresponding 2-nitro-4,5-dimethoxybenzyl analog generated the desired HNO and CF3SO2- as a minor pathway, with competing photoinduced O-N bond cleavage to release CF3SO2NH2 as the major photodecomposition pathway. Photolysis of the corresponding -SO2CH3 analogs resulted in O-N bond cleavage only. The presence of the o-nitro substituent was shown to be essential for photoactivity. Photorelease of the parent HNO donor CH3SO2NHOH was observed as the major product upon irradiation of o-NO2Bn-OC(O)ON(H)SO2CH3, with the desired HNO release and O-N bond cleavage occurring as minor pathways. Photoproduct quantum yields for each species have been determined by actinometry. The effect of solvent, pH and air on the mechanism of photodecomposition was studied for o-NO2Bn-ON(H)SO2CH3. The ratio of the solvents in the solvent mixture (CH3CN and phosphate buffer, pH 7.0), the pH of the aqueous component of the buffer, and the presence of oxygen did not affect the amount of each photoproduct and the observed rate constant for O-N bond cleavage. Possible mechanisms for the various pathways are proposed.
