21244-24-6Relevant academic research and scientific papers
Desymmetrization of an Octahedral Coordination Complex Inside a Self-Assembled Exoskeleton
Johnstone, Mark D.,Schwarze, Eike K.,Ahrens, Jennifer,Schwarzer, Dirk,Holstein, Julian J.,Dittrich, Birger,Pfeffer, Frederick M.,Clever, Guido H.
, p. 10791 - 10795 (2016)
The synthesis of a centrally functionalized, ribbon-shaped [6]polynorbornane ligand L that self-assembles with PdIIcations into a {Pd2L4} coordination cage is reported. The shape-persistent {Pd2L4} cage contains two axial cationic centers and an array of four equatorial H-bond donors pointing directly towards the center of the cavity. This precisely defined supramolecular environment is complementary to the geometry of classic octahedral complexes [M(XY)6] with six diatomic ligands. Very strong binding of [Pt(CN)6]2?to the cage was observed, with the structure of the host–guest complex {[Pt(CN)6]@Pd2L4} supported by NMR spectroscopy, MS, and X-ray data. The self-assembled shell imprints its geometry on the encapsulated guest, and desymmetrization of the octahedral platinum species by the influence of the D4h-symmetric second coordination sphere was evidenced by IR spectroscopy. [Fe(CN)6]3?and square-planar [Pt(CN)4]2?were strongly bound. Smaller octahedral anions such as [SiF6]2?, neutral carbonyl complexes ([M(CO)6]; M=Cr, Mo, W) and the linear [Ag(CN)2]?anion were only weakly bound, showing that both size and charge match are key factors for high-affinity binding.
Catalytic SNAr Hydroxylation and Alkoxylation of Aryl Fluorides
Kang, Qi-Kai,Li, Ke,Li, Yuntong,Lin, Yunzhi,Shi, Hang,Xu, Lun
supporting information, p. 20391 - 20399 (2021/08/13)
Nucleophilic aromatic substitution (SNAr) is a powerful strategy for incorporating a heteroatom into an aromatic ring by displacement of a leaving group with a nucleophile, but this method is limited to electron-deficient arenes. We have now established a reliable method for accessing phenols and phenyl alkyl ethers via catalytic SNAr reactions. The method is applicable to a broad array of electron-rich and neutral aryl fluorides, which are inert under classical SNAr conditions. Although the mechanism of SNAr reactions involving metal arene complexes is hypothesized to involve a stepwise pathway (addition followed by elimination), experimental data that support this hypothesis is still under exploration. Mechanistic studies and DFT calculations suggest either a stepwise or stepwise-like energy profile. Notably, we isolated a rhodium η5-cyclohexadienyl complex intermediate with an sp3-hybridized carbon bearing both a nucleophile and a leaving group.
One-Pot Substitution of Aliphatic Alcohols Mediated by Sulfuryl Fluoride
Dubois, Rudy,Epifanov, Maxim,Hodgson, Jack W.,Mo, Jia Yi,Sammis, Glenn M.
supporting information, p. 4958 - 4962 (2020/04/22)
The Mitsunobu reaction is a powerful transformation for the one-pot activation and substitution of aliphatic alcohols. Significant efforts have focused on modifying the classic conditions to overcome problems associated with purification from phosphine-based byproducts. Herein, we report a phosphine free method for alcohol activation and substitution that is mediated by sulfuryl fluoride. This new method is effective for a wide range of primary alcohols using phthalimide, di-tert-butyl-iminodicarboxylate, and aromatic thiol nucleophiles in 74 % average yield. Activated carbon nucleophiles and a deactivated phenol were also effective for this reaction in good yields. Secondary alcohols were also successful substrates using aryl thiols, affording the corresponding sulfides in 56 % average yield with enantiomeric ratios up to 99:1. This new protocol has a distinct synthetic advantage over many existing phosphine-based methods as the byproducts are readily separable. This feature was exploited in several examples that did not require chromatography for purification. Furthermore, the mild reaction conditions enabled further in situ derivatization for the one-pot conversion of alcohols to amines or sulfones. This method also provides a boarder nucleophile scope compared to existing phosphine-free methods.
Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
supporting information, p. 2107 - 2116 (2019/03/26)
An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
Simple and rapid p-methoxybenzylation of hydroxy and amide groups at room temperature by NaOt-Bu and DMSO
Hamada, Shohei,Sugimoto, Koichi,Iida, Masashi,Furuta, Takumi
supporting information, (2019/11/13)
The p-methoxybenzylation of hydroxy and amide groups by p-methoxybenzyl chloride utilizing NaOt-Bu in DMSO is described. p-Methoxybenzylation of sterically hindered menthol using NaOt-Bu in DMSO proceeded faster than the commonly used methods which use Na
Alkoxide-Catalyzed Hydrosilylation of Cyclic Imides to Isoquinolines via Tandem Reduction and Rearrangement
Wu, Xiaoyu,Ding, Guangni,Yang, Liqun,Lu, Wenkui,Li, Wanfang,Zhang, Zhaoguo,Xie, Xiaomin
supporting information, p. 5610 - 5613 (2018/09/12)
An alkoxide-catalyzed hydrosilylation of cyclic imides to isoquinolines was realized via tandem reduction and rearrangement. Using TMSOK as the catalyst and (EtO)2MeSiH as the reductant, a series of cyclic imides containing different functional groups were reduced to the corresponding 3-aryl isoquinolines in moderate to good yields. The scenario of the reaction pathway was supposed to involve the reduction of imides to ω-hydroxylactams, which underwent rearrangement in the presence of a base catalyst, and then the carbonyl reduction, followed by siloxy elimination.
Synthetic method for N-substituted imide
-
Paragraph 0016; 0028; 0029; 0030; 0031, (2017/04/20)
The invention provides a synthetic method for N-substituted imide. According to the method, aromatic ketone and amine are used as substrates, air or oxygen is used as an oxygen source, and cyclic imide is produced under liquid phase conditions under the action of a catalyst. The method is mild in conditions, high in oxidation efficiency and high in product yield; and since the method uses air or oxygen as the oxygen source, the method is economic and environment-friendly and has good application prospect.
COMPOSITIONS FOR PROMOTING READTHROUGH OF PREMATURE TERMINATION CODONS, AND METHODS OF USING THE SAME
-
Page/Page column 214; 216; 217; 224, (2017/04/11)
Disclosed are compounds of general formula (I) that promote readthrough of a premature termination codon (PTC) of an RNA molecule in a translation system, and their use, alone or in combination with other compounds, such as aminoglycoside, to treat diseases or disorders ameliorated by modulation of a premature termination codon (PTC) of an RNA molecule in a translation system. The disorder or disease may be Dystrophic epidermolysis bullosa, Batten disease, Duchenne muscular dystrophy, cancer, and spinal muscular atrophy. Ar-L-B (I)
A class of 2, 5 - disubstituted benzenes sulfonamide compounds and their preparation and use
-
Paragraph 0108; 0110-0112, (2017/10/07)
The invention relates to 2,5-disubstituted benzsulfamide compounds, a preparation method thereof and applications thereof, and particularly relates to compounds shown in the formula I, a preparation method thereof, pharmaceutical compositions thereof, and applications of the compounds as a CCR6 antagonist in preparing medicines for treating CCR6-mediated diseases, wherein the CCR6-mediated diseases comprise autoimmune diseases, inflammation, psoriasis, multiple sclerosis or cancer, and the like.
An efficient synthesis of N-substituted phthalimides using SiO2-tpy-Nb as heterogeneous and reusable catalyst
Wan, Li,Sun, Xiaoning,Shi, Songjie,Zhang, Jiawei,Li, Xin,Li, Zhenjiang,Guo, Kai
, p. 30 - 34 (2016/09/28)
A novel and efficient heterogeneous catalyst SiO2-tpy-Nb was developed, and its application in the preparation of N-substituted phthalimides from o-phthalic acids or anhydrides with amines provides the desired products in good to excellent yields. The catalyst was stable and recoverable for eight consecutive cycles without a significant loss in its activity. Furthermore, the catalyst is applicable in continuous flow which indicates its potential utilization in industrialization.
