共查询到20条相似文献,搜索用时 14 毫秒
1.
2.
Hiromi Hamamoto 《Tetrahedron letters》2007,48(24):4239-4242
A recyclable catalytic system under heterogeneous phase-transfer catalysis conditions was designed by using polyacrylamide-bound tungstate. A convenient method for the oxidative direct transformation of benzilic amines to carbonyls with hydrogen peroxide was then developed. 相似文献
3.
《中国化学快报》2020,31(12):3267-3270
An efficient procedure for the selective preparation of hydroxy-, carbonyl- and acetal-containing 2-pyrrolidinones has been developed through radical cyclization of 1,6-dienes initiated by α-C(sp3)–H functionalization of alcohols. This protocol could be conducted at catalyst-free conditions at relatively low temperature (80 °C) by employing commercially available tert-butyl peroxybenzoate (TBPB) as the oxidant. 相似文献
4.
Fu-Hua Qin Xun-Jie Huang Yi Liu Hongze Liang Qiang Li Zhong Cao Wen-Ting Wei Wei-Min He 《中国化学快报》2021,31(12):3267-3270
An efficient procedure for the selective preparation of hydroxy-, carbonyl- and acetal-containing 2-pyrrolidinones has been developed through radical cyclization of 1,6-dienes initiated by α-C(sp3)-H functionalization of alcohols. This protocol could be conducted at catalyst-free conditions at relatively low temperature (80 ℃) by employing commercially available tert-butyl peroxybenzoate (TBPB) as the oxidant. 相似文献
5.
CO2 capture and release behaviors of three amidines bearing silatranyl group in DMSO solution were evaluated under dry conditions containing a very small amount of water. A six-membered cyclic amidine with silatranyl group captured CO2 at 25 °C under atmospheric pressure quantitatively, and the trapped CO2 was released at 60 °C under Ar atmosphere. A five-membered cyclic amidine with silatranyl group also captured CO2, but less efficiently, under the same conditions as above. In contrast, an acyclic amidine with silatranyl group did not capture CO2 at all, as expected from the poor CO2-capturing ability of the acyclic amidine moiety. 相似文献
6.
Kalyan Kumar PasunootiHua Chai Chantel Nixon JensenBala Kishan Gorityala Siming WangXue-Wei Liu 《Tetrahedron letters》2011,52(1):80-84
The synthesis of dihydropyrimidinones via a clean multi-component Biginelli reaction under microwave irradiation is reported. The copper-catalyzed process proved to be simple, efficient, economical, and environmentally friendly. 相似文献
7.
An enantioselective carboxylative cyclization of propargylic alcohols and CO2 was realized under mild conditions,based on a kinetic resolution strategy,which enabled the synthesis of chiral cyclic carbonates and propargylic alcohols with promising yield and enantioselectivity simultaneously. 相似文献
8.
9.
《Green Chemistry Letters and Reviews》2013,6(3):249-256
Abstract An incredibly elementary procedure for the effective synthesis of 1,5-benzodiazepine derivatives using triethyl ammonium acetate (TEAA) [Et3NH][CH3COO] ionic liquid has been developed. TEAA was found to be practical, inexpensive, reusable and has a simple work-up procedure, which is absent in other catalyst. The role of TEAA as the reaction medium as well as the catalyst has shown the benefits of the use of TEAA in organic synthesis. The effect of [Et3NH][CH3COO] on the synthesis of 1,5-benzodiazepine derivatives has been studied and results are provided herein. 相似文献
10.
11.
An efficient ionic liquid system was developed for the preparation of various heterocycle-fused pyrimidine-2, 4(1H,3H)-diones in moderate to excellent yields (52–95%). It was found that [HDBN+][TFE?], a simple and easily prepared ionic liquid, could act as both the solvent and reaction promoter, and that the reactions could be efficiently carried out at atmospheric pressures of CO2. 相似文献
12.
本文研究了离子液体1-乙基-3-甲基咪唑二乙基磷酸酯([EMIM][(EtO)2PO2])中醋酸银(AgOAc)对CO2与炔醇反应生成-亚甲基环状碳酸酯的催化性能,发现该反应可以在温和的条件下进行.在AgOAc/[EMIM][(EtO)2PO2]催化体系中,30℃、4 MPa CO2压力下,反应6h时-亚甲基环状碳酸酯的产率为97%;当压力降到0.5 MPa时,反应24 h产物产率为65.8%.[EMIM][(EtO)2PO2]在反应中起到了溶剂和碱的双重作用.AgOAc/[EMIM][(EtO)2PO2]体系重复利用3次活性仅略有下降.另外,该体系也可用于催化CO2与其他炔醇(3-甲基-1-戊炔-3-醇、3,5-二甲基-1-己炔-3-醇和2-苯基-3-丁炔-2-醇)的反应. 相似文献
13.
Easily prepared choline iodide is an active catalyst for the synthesis of cyclic carbonates through the coupling reaction of CO2 and epoxides using low pressure (1 MPa), moderate temperature (85 ºC) and green solvents (ethanol and propan-2-ol). The effects of reaction temperature, pressure, reaction time and amount of catalyst used were also investigated. The results showed moderate to high yields and excellent selectivities of cyclic carbonates with vinyl or acrylate groups under mild reaction conditions. The heterogenization of choline over a Merrifield resin gives access to a supported catalyst with good recyclability and reactivity that can be extended to a variety of terminal epoxide substrates. 相似文献
14.
Qing-Wen Gui Fan Teng Zhou-Chao Li Zhi-Yuan Xiong Xue-Feng Jin Ying-Wu Lin Zhong Cao Wei-Min He 《中国化学快报》2021,32(6):1907-1910
An efficient and eco-friendly protocol for synthesizing difluoromethylated oxindoles through a visiblelight induced one-pot tandem reaction of N-arylacrylamides, difluoroacetic acid and Ph I(OAc)_2 was developed. This reaction proceeded in the absence of any additive, base, metal-catalyst and external photosensitizer, using cheap and easily available CHF_2CO_2H as the difluoromethylation reagent and bulk biomass-derived 2-Me THF as the sole solvent. 26 Examples of N-arylacrylamide substrates were investigated, and all of them successfully underwent difluoromethylation to deliver the target products in good to excellent yields. 相似文献
15.
A mild esterification process in phosphonium salt ionic liquid 总被引:2,自引:0,他引:2
James McNulty Sreedhar Cheekoori Vladimir Larichev Al J. Robertson 《Tetrahedron letters》2005,46(21):3641-3644
A general, high yielding procedure is described for the esterification of carboxylic acids through carboxylate alkylation in phosphonium salt ionic liquid. 相似文献
16.
17.
CO2是最重要的可再生碳源之一.为了将CO2转化为有用的有机化合物,我们研究了二种模型硅基"废"材料—乙硅烷和硅粉的反应活性.在这些反应中,氟盐的催化活性最高,在常压、在质子源水和硅基还原剂的存在下,CO2可转化为甲酸.原位NMR和动力学分析表明,含氢硅烷和五配位的硅物种分别是反应中间物和活性物种. 相似文献
18.
《Journal of Energy Chemistry》2014,23(1):22-28
We reported a bifunctional material, Cr-salen implanted conjugated microporous polymer (Cr-CMP), which is able to capture excellent CO2 amounts and has a remarkable catalytic activity towards the cycloaddition reaction of CO2 to epoxides forming cyclic carbonates at mild conditions without additional solvents. This heterogeneous Cr-CMP catalyst has a superior catalytic activity to its related homogeneous catalyst and can be reused more than ten times without a significant decrease in catalytic activity. 相似文献
19.
通过共沉淀法制备了一系列Mn掺杂量不同的Ce1-xMnxO2催化剂, 并将其用于催化CO2和甲醇直接合成碳酸二甲酯(DMC). 通过X射线衍射(XRD)、 氮气吸附-脱附、 透射电子显微镜(TEM)、 X射线光电子能谱(XPS)和程序升温脱附(TPD)等手段研究了Ce1-xMnxO2表面性质对催化CO2和甲醇直接合成DMC反应活性的影响. 结果表明, Mn离子进入CeO2晶格中形成固溶体, 随着Mn掺杂量增加, 催化剂表面弱酸碱位数量逐渐降低, 中强酸碱和强酸碱位数量增加, 催化剂表面氧空位含量呈先增加后减少的变化趋势, 当Mn掺杂量较少时, 催化剂表面Mn2+比例较高, 有利于Ce4++Mn2+→Ce3++Mn3+反应的进行, 促进催化剂表面氧空位生成; 进一步提高Mn掺杂量时, 催化剂表面Mn4+比例提高, 有利于Ce3++Mn4+→Ce4++Mn3+反应的进行, 导致催化剂表面氧空位含量减少. 研究发现Ce1-xMnxO2催化剂活性与表面氧空位含量线性相关. 相似文献
20.
A cost-effective and eco-friendly straightforward synthesis of new bis-isoxazolyl amino dihydro-1H-indol-4(5H)-ones is successfully achieved via one-pot three-component reaction of N-isoxazolyl enaminone, aryl glyoxal monohydrates and 4-amino-3-methyl-5-styrylisoxazoles by using water as a reaction medium and acetic acid (AcOH) as cheap and green promoter. The protocol proves to be an efficient and environmentally benign in terms of high yields, low reaction time, operational simplicity, metal-free and wide substrates scope. Most important of all, this reaction process is green. 相似文献