- Organosilatranes with thioester-anchored heterocyclic ring assembly: Cu2+ ion binding and fabrication of hybrid silica nanoparticles
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This work presents the design, synthesis, UV-Vis absorption properties and Cu2+ ion binding of the organo-silicon complexes (3a-h) with different coordination abilities that are derived from mercaptopropylsilatrane (MPS) and respective heteroaromatic carboxylic acids (1a-h). The prepared thioester based organosilatranes (ThE-OS) have been meticulously characterized by a series of characterization techniques such as elemental analyses, FT-IR, NMR (1H, 13C), LC-MS, and structure of 3e was unambiguously determined by X-ray single crystal analyses. All the compounds have shown judicious absorption enhancement in the intensity as well as λmax values on binding with Cu2+ ions compared to other surveyed metal ions. In addition, it is for the first time that the hybrid silica nanoparticles (H-SiNPs) bearing a thioester linkage in the silica framework are reported. The synthesis was achieved conveniently by an in situ co-condensation reaction of tetraethyl orthosilicate (TEOS) with the corresponding ThE-OS. The derivatization of silica is confirmed by FT-IR, 13C and 29Si solid state CP-MAS NMR, UV-Vis, TEM, XRD, TGA and EDX techniques. Furthermore, the H-SiNPs have exhibited greater affinity towards Cu2+ ions than the parent ThE-OS.
- Singh, Gurjaspreet,Rani, Sunita,Saroa, Amandeep,Girdhar, Shally,Singh, Jandeep,Arora, Aanchal,Aulakh, Darpandeep,Wriedt, Mario
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- Catalytic asymmetric construction of pyrroloindolines via an in situ generated magnesium catalyst
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An asymmetric formal [3 + 2]-cycloaddition between mesoaziridines and C3-alkylindoles mediated by an in situ generated magnesium catalyst was developed for asymmetric construction of pyrroloindolines. A variety of pyrroloindolines could be obtained by employing commercial available ligands with the assistance of an easily prepared achiral ligand. (Chemical Equation Presented).
- Wang, Linqing,Yang, Dongxu,Han, Fengxia,Li, Dan,Zhao, Depeng,Wang, Rui
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- Practical Chemoselective Acylation: Organocatalytic Chemodivergent Esterification and Amidation of Amino Alcohols with N-Carbonylimidazoles
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Chemoselective transformations are a cornerstone of efficient organic synthesis; however, achieving this goal for even simple transformations, such as acylation reactions, is often a challenge. We report that N-carbonylimidazoles enable catalytic chemodivergent aniline or alcohol acylation in the presence of pyridinium ions or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), respectively. Both acylation reactions display high and broad chemoselectivity for the target group. Unprecedented levels of chemoselectivity were observed in the DBU-catalyzed esterification: A single esterification product was obtained from a molecule containing primary aniline, alcohol, phenol, secondary amide, and N?H indole groups. These acylation reactions are highly practical as they involve only readily available, inexpensive, and relatively safe reagents; can be performed on a multigram scale; and can be used on carboxylic acids directly by in situ formation of the acylimidazole electrophile.
- Nelson, Hope,Richard, William,Brown, Hailee,Medlin, Abigail,Light, Christina,Heller, Stephen T.
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supporting information
p. 22818 - 22825
(2021/09/13)
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- Silver-Catalyzed Acyl Nitrene Transfer Reactions Involving Dioxazolones: Direct Assembly of N-Acylureas
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Dioxazolones and isocyanides are useful synthetic building blocks, and have attracted significant attention from researchers. However, the silver-catalyzed nitrene transfer reaction of dioxazolones has not been investigated to date. Herein, a silver-catalyzed acyl nitrene transfer reaction involving dioxazolones, isocyanides, and water was realized in the presence of Ag2O to afford a series of N-acylureas in moderate to good yields.
- Yang, Zheng-Lin,Xu, Xin-Liang,Chen, Xue-Rong,Mao, Zhi-Feng,Zhou, Yi-Feng
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supporting information
p. 648 - 652
(2020/12/21)
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- Efficient Synthesis of α-Ketothioamides From α-Nitroketones, Amines or DMF and Elemental Sulfur Under Oxidant-Free Conditions
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We have developed a practical, general protocol for denitration of readily available α-nitroketones with sulfur and amines to access a broad range of α-ketothioamides under mild conditions. Such a reaction proceeds under metal-, oxidant-, and catalyst-free conditions to provide synthetically useful α-ketothioamides. Furthermore, the mild reaction conditions tolerate a wide range of substrates especially for the synthesis of aliphatic α-ketothioamides which are rarely reported.
- Zhang, Zhenlei,Yang, Jiusi,Yu, Renjie,Wu, Kairui,Bu, Jiping,Li, Shaoke,Qian, Peng,Sheng, Liangquan
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supporting information
p. 5209 - 5212
(2021/10/19)
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- Furoate cigarette spice, preparation method of furoate cigarette spice and application of furoate cigarette spice to cigarettes
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The invention belongs to the technical field of cigarette spice, and particularly relates to furoate cigarette spice, a preparation method of the furoate cigarette spice and application of the furoatecigarette spice to cigarettes. The cigarette spice uses furoic acid as raw materials, and another alcohol containing spice ingredients as ligands; through N,N'-carbonyl di-imidazole activation to synthesize the novel furoate sweet aroma compound; the compound has a simple structure; the synthesis method is simple; the burning smoking process thermal cracking study is performed on the compound; furan ingredients and other substances with unique fragrance features can be obtained through cracking. When the compound is applied to tobacco flavoring, the smoke gas richness can be enhanced; the smoke gas mouthfeel can be coordinated; the miscellaneous qi is reduced; the irritation is reduced; the aftertaste is improved; meanwhile, the mouthfeel such as sweet aroma and fruit aroma can also be obtained during the cigarette smoking evaluation through the spice addition; the smoking quality is improved.
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Paragraph 0026; 0029
(2021/03/25)
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- Chemoselective acylation of 2-amino-8-quinolinol in the generation of C2-amides or C8-esters
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Two different ways to carry out the chemoselective acylation of 2-amino-8-quinolinol with unique features to generate C2-amides or C8-esters were developed. The coupling reaction with a variety of carboxylic acids using EDCI and DMAP provided C8-ester derivatives, whereas N-heteroaromatic acids were not introduced on the C8-hydroxy group, but rather on the C2-amino group under the same conditions. To obtain C2-amides selectively, the anionic nucleophile from 2-amino-8-quinolinol was treated with less reactive acyl imidazolides or esters.
- Park, Yongseok,Fei, Xiang,Yuan, Yue,Lee, Sanha,Hur, Joonseong,Park, Sung Jean,Jung, Jae-Kyung,Seo, Seung-Yong
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p. 41955 - 41961
(2017/09/12)
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- Organo-functionalized trimethoxysilanes featuring thioester linkage: Synthetic and UV–Vis spectral investigations
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The current work reveals a series of new organo-functionalized trimethoxysilanes (OfTMS) linked via a 3C tether to the thioester group along with the inclusion of versatile aromatic and heteroaromatic sequences. The synthetic procedure implicates the one-pot thioesterification reaction of the precursor carboxylic acids (1a-r) with 3-mercaptopropyltrimethoxysilane (MPTMS), stimulated by 1,1′-carbonyldiimidazole (CDI). The OfTMS have been attentively characterized by elemental analysis, infrared and [1H, 13C] NMR spectroscopic techniques. The UV–Vis absorption behaviour demonstrates that the alkoxysilanes possess high sensitivity to the changes caused in the environment on account of different substitutions. Furthermore, the solvent effect on the absorption spectra has been scrutinized and quantified using the Kamlet-Taft approach. Importantly, the fabricated stable alkoxysilanes can be aspired for advance applications in the field of material science.
- Singh, Gurjaspreet,Rani, Sunita,Saroa, Amandeep,Arora, Aanchal
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- Synthesis of 6-substituted-4-hydroxy-2-pyridinones via intramolecular ketene trapping of functionalized enamine-dioxinones
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The synthesis of various 6-substituted-4-hydroxy-2-pyridinones is reported. The functionalized keto-dioxinones were constructed via a diethylzinc mediated crossed Claisen condensation reaction and subsequent enamine formation, thermolysis, and cyclization
- Patel, Bhavesh H.,Mason, Andrew M.,Barrett, Anthony G.M.
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supporting information; experimental part
p. 5156 - 5159
(2011/11/29)
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- Expedient synthesis of 3-hydroxyisoquinolines and 2-hydroxy-1,4- naphthoquinones via one-pot aryne acyl-alkylation/condensation
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A convenient method is disclosed for the synthesis of both 3-hydroxyisoquinolines and 2-hydroxy-1,4-naphthoquinones from β-ketoesters using a one-pot aryne acyl-alkylation/condensation procedure. When performed in conjunction with a one-step method for the synthesis of the β-ketoester substrates, this method provides a new route to these polyaromatic structures in only two steps from commercially available carboxylic acid starting materials. The utility of this approach is demonstrated in the synthesis of the atropisomeric P,N-ligand, QUINAP. The Royal Society of Chemistry 2009.
- Allan, Kevin M.,Hong, Boram D.,Stoltz, Brian M.
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supporting information; experimental part
p. 4960 - 4964
(2010/02/15)
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- Design, synthesis, and evaluation of inhibitors for severe acute respiratory syndrome 3C-like protease based on phthalhydrazide ketones or heteroaromatic esters
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The 3C-like protease (3CLpro), which controls the severe acute respiratory syndrome (SARS) coronavirus replication, has been identified as a potential target for drug design in the treatment of SARS. A series of tetrapeptide phthalhydrazide ketones, pyridinyl esters, and their analogs have been designed, synthesized, and evaluated as potential SARS 3CLpro inhibitors. Some pyridinyl esters are identified as very potent inhibitors, with IC50 values in the nanomolar range (50-65 nM). Electrospray mass spectrometry indicates a mechanism involving acylation of the active site cysteine thiol for this class of inhibitors.
- Zhang, Jianmin,Pettersson, Hanna I.,Huitema, Carly,Niu, Chunying,Yin, Jiang,James, Michael N. G.,Eltis, Lindsay D.,Vederas, John C.
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p. 1850 - 1864
(2008/02/02)
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- A process for the synthesis of βketoesters using in-situ generated (trimethylsilyl)malonates
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(TMS)ethyl malonate can be generated in-situ by treating potassium ethyl malonate with trimethylsilyl chloride and acylated with aliphatic or aromatic acyl imidazoles or chlorides in the presence of DBU to prepare a variety of β-ketoesters. This constitutes a high yield method for preparing β-ketoesters, which also can be extended to the formation of alkylidene malonates.
- Wang, Xui,Monte, William T.,Napier, James J.,Ghannam, Ameen
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p. 9323 - 9326
(2007/10/02)
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- Facile Conversions of Carboxylic Acids into Amides, Esters, and Thioesters Using 1,1'-Oxalyldiimidazole and 1,1'-Oxalyldi(1,2,4-triazole)
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Aliphatic, aromatic, and heteroaromatic carboxylic acids react with 1,1'-oxalyldiimidazole (1) or 1,1'-oxalyldi(1,2,4-triazole) (2) in acetonitrile for 40 min at 40 degC to give the corresponding 1-acylazole intermediates (11), which promptly undergo aminolysis and alcoholysis to form amides (13) including dipeptides (14), esters (16), and thioesters (19).These findings show that both 1 and 2 can be utilized as condensing reagents for the synthesis of carboxylic acid derivatives.Keywords --- 1,1'-oxalyldiimidazole; 1,1'-oxalyldi(1,2,4-triazole); 1,1'-carbonyldiimidazole; 1-acylazole; condensing reagent; amidation; esterification; dipeptide; aminolysis; alcoholysis
- Kitagawa, Tokujiro,Kuroda, Hiroko,Sasaki, Hideaki,Kawasaki, Koichi
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p. 4294 - 4301
(2007/10/02)
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