- Carboxyl Methyltransferase Catalysed Formation of Mono- and Dimethyl Esters under Aqueous Conditions: Application in Cascade Biocatalysis
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Carboxyl methyltransferase (CMT) enzymes catalyse the biomethylation of carboxylic acids under aqueous conditions and have potential for use in synthetic enzyme cascades. Herein we report that the enzyme FtpM from Aspergillus fumigatus can methylate a broad range of aromatic mono- and dicarboxylic acids in good to excellent conversions. The enzyme shows high regioselectivity on its natural substrate fumaryl-l-tyrosine, trans, trans-muconic acid and a number of the dicarboxylic acids tested. Dicarboxylic acids are generally better substrates than monocarboxylic acids, although some substituents are able to compensate for the absence of a second acid group. For dicarboxylic acids, the second methylation shows strong pH dependency with an optimum at pH 5.5–6. Potential for application in industrial biotechnology was demonstrated in a cascade for the production of a bioplastics precursor (FDME) from bioderived 5-hydroxymethylfurfural (HMF).
- Ashbrook, Chloe,Carnell, Andrew J.,Goulding, Ellie,Hatton, Harry,Johnson, James R.,Kershaw, Neil M.,McCue, Hannah V.,Rigden, Daniel J.,Ward, Lucy C.
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supporting information
(2022/02/21)
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- A Mild Heteroatom (O -, N -, and S -) Methylation Protocol Using Trimethyl Phosphate (TMP)-Ca(OH) 2Combination
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A mild heteroatom methylation protocol using trimethyl phosphate (TMP)-Ca(OH)2combination has been developed, which proceeds in DMF, or water, or under neat conditions, at 80 °C or at room temperature. A series of O-, N-, and S-nucleophiles, including phenols, sulfonamides, N-heterocycles, such as 9H-carbazole, indole derivatives, and 1,8-naphthalimide, and aryl/alkyl thiols, are suitable substrates for this protocol. The high efficiency, operational simplicity, scalability, cost-efficiency, and environmentally friendly nature of this protocol make it an attractive alternative to the conventional base-promoted heteroatom methylation procedures.
- Tang, Yu,Yu, Biao
-
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- Beyond Basicity: Discovery of Nonbasic DENV-2 Protease Inhibitors with Potent Activity in Cell Culture
-
The viral serine protease NS2B-NS3 is one of the promising targets for drug discovery against dengue virus and other flaviviruses. The molecular recognition preferences of the protease favor basic, positively charged moieties as substrates and inhibitors, which leads to pharmacokinetic liabilities and off-target interactions with host proteases such as thrombin. We here present the results of efforts that were aimed specifically at the discovery and development of noncharged, small-molecular inhibitors of the flaviviral proteases. A key factor in the discovery of these compounds was a cellular reporter gene assay for the dengue protease, the DENV2proHeLa system. Extensive structure-activity relationship explorations resulted in novel benzamide derivatives with submicromolar activities in viral replication assays (EC50 0.24 μM), selectivity against off-target proteases, and negligible cytotoxicity. This structural class has increased drug-likeness compared to most of the previously published active-site-directed flaviviral protease inhibitors and includes promising candidates for further preclinical development.
- Kühl, Nikos,Leuthold, Mila M.,Behnam, Mira A. M.,Klein, Christian D.
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p. 4567 - 4587
(2021/05/06)
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- Antibacterial Prenylated p-Hydroxybenzoic Acid Derivatives from Oberonia myosurus and Identification of Putative Prenyltransferases
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Twelve hitherto unknown tandem prenylated p-hydroxybenzoic acid derivatives, namely, oberoniamyosurusins A-L, together with five known derivatives, were isolated from an EtOH extract of the whole parts of the plant Oberonia myosurus. Compounds 10, 13, and 17 exhibited moderate inhibitory activity against Staphylococcus aureus subsp. aureus ATCC29213 with MIC50 values ranging from 7.6 to 23 μg/mL. To determine the biosynthetic pathway of this class of tandem prenyl-substituted compounds, the full-length transcriptome of O. myosurus was sequenced, yielding 19.09 Gb of clean data and 10 949 nonredundant sequences. Two isoforms of p-hydroxybenzoic acid prenyltransferases were annotated and functionally characterized as the enzymes that might be involved in the biosynthesis of nervogenic acid (13) in Pichia pastoris.
- Ren, Fu-Cai,Liu, Li,Lv, Yong-Feng,Bai, Xue,Kang, Qian-Jin,Hu, Xiao-Jing,Zhuang, Hong-Dan,Yang, Liu,Hu, Jiang-Miao,Zhou, Jun
-
supporting information
p. 417 - 426
(2021/02/26)
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- Photocatalytic Reductive C-O Bond Cleavage of Alkyl Aryl Ethers by Using Carbazole Catalysts with Cesium Carbonate
-
Methods to activate the relatively stable ether C-O bonds and convert them to other functional groups are desirable. One-electron reduction of ethers is a potentially promising route to cleave the C-O bond. However, owing to the highly negative redox potential of alkyl aryl ethers (Ered -2.6 V vs SCE), this mode of ether C-O bond activation is challenging. Herein, we report the visible-light-induced photocatalytic cleavage of the alkyl aryl ether C-O bond using a carbazole-based organic photocatalyst (PC). Both benzylic and non-benzylic aryl ethers underwent C-O bond cleavage to form the corresponding phenol products. Addition of Cs2CO3 was beneficial, especially in reactions using a N-H carbazole PC. The reaction was proposed to occur via single-electron transfer (SET) from the excited-state carbazole to the substrate ether. Interaction of the N-H carbazole PC with Cs2CO3 via hydrogen bonding exists, which enables a deprotonation-assisted electron-transfer mechanism to operate. In addition, the Lewis acidic Cs cation interacts with the substrate alkyl aryl ether to activate it as an electron acceptor. The high reducing ability of the carbazole combined with the beneficial effects of Cs2CO3 made this otherwise formidable SET event possible.
- Yabuta, Tatsushi,Hayashi, Masahiko,Matsubara, Ryosuke
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p. 2545 - 2555
(2021/02/01)
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- Cleavage of Carboxylic Esters by Aluminum and Iodine
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A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
- Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
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p. 4254 - 4261
(2021/03/09)
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- Method for hydrolyzing diarylether compound to generate aryl phenol compound
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The invention discloses a method for hydrolyzing a diarylether compound to generate an arylphenol compound. According to the method, visible light is utilized to excite a photosensitizer for catalysis. In a reaction solvent, the raw material in the formula (1) breaks a C (sp2)-O bond under the auxiliary action of acid, and hydrolysis is performed to obtain the bimolecular aryl phenol compounds in the formula (3) and the formula (4). The method can catalyze the reaction at room temperature, is green and environment-friendly, and is easy to operate; the universality is wide, the reaction yield is relatively high, and the tolerance of functional groups is strong; the synthesis method not only can realize small-scale hydrolysis conversion of various diarylether compounds, but also can realize hydrolysis of herbicidal ether, triclosan and a lignin template substrate, and even can realize large-scale hydrolysis of triclosan and the lignin template substrate to realize gram-level degradation. A new strategy is provided for recovering phenol derivatives through lignin hydrolysis, degrading pesticides and purifying wastewater containing a degerming agent or herbicide. The method has wide application prospect and use value.
- -
-
Paragraph 0093-0095
(2021/09/29)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
-
A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
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p. 6591 - 6597
(2021/09/10)
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- Site-Selective C-H alkylation of Complex Arenes by a Two-Step Aryl Thianthrenation-Reductive Alkylation Sequence
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Herein, we present an undirected para-selective two-step C-H alkylation of complex arenes useful for late-stage functionalization. The combination of a site-selective C-H thianthrenation with palladium-catalyzed reductive electrophile cross-coupling grants access to a diverse range of synthetically useful alkylated arenes which cannot be accessed otherwise with comparable selectivity, diversity, and practicality. The robustness of this transformation is further demonstrated by thianthrenium-based reductive coupling of two complex fragments.
- Granatino, Paola,Lansbergen, Beatrice,Ritter, Tobias
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p. 7909 - 7914
(2021/06/27)
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- Erratum: Site-Selective C-H Alkylation of Complex Arenes by a Two-Step Aryl Thianthrenation-Reductive Alkylation Sequence (J. Am. Chem. Soc. (2021) 143: 21 (7909?7914) DOI: 10.1021/jacs.1c03459)
-
Page 7912. In our previous Communication, we inadvertently drew the substrates derived from the molecule pyriproxyfen with incorrect connectivity of the pyriproxyfen molecule (meta instead of para was drawn), omitted a methylene group from compound 13, and drew an epimer of compound 20 in Scheme 3. These drawing errors have been corrected in the corrected Scheme 3 shown here. As a further clarification, we have commented in the revised Supporting Information about the undefined stereocenter of compound 21. The findings and conclusions of the original communication remain unchanged. We apologize for the errors and for any inconvenience that this may have caused the readers of JACS.
- Granatino, Paola,Lansbergen, Beatrice,Ritter, Tobias
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p. 10477 - 10478
(2021/07/26)
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- Iron-Catalyzed Halogen Exchange of Trifluoromethyl Arenes**
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The facile production of ArCF2X and ArCX3 from ArCF3 using catalytic iron(III)halides is reported, which constitutes the first iron-catalyzed halogen exchange for non-aromatic C?F bonds. Theoretical calculations suggest direct activation of C?F bonds by iron coordination. ArCX3 and ArCF2X products of the reaction are synthetically valuable due to their diversification potential. In particular, chloro- and bromodifluoromethyl arenes (ArCF2Cl, ArCF2Br respectively) provide access to a myriad of difluoromethyl arene derivatives (ArCF2R). To optimize for mono-halogen exchange, a statistical method called Design of Experiments was used. Optimized parameters were successfully applied to electron rich and electron deficient aromatic substrates, and to the late stage diversification of flufenoxuron, a commercial insecticide. These methods are highly practical, being run at convenient temperatures and using inexpensive common reagents.
- Dorian, Andreas,Landgreen, Emily J.,Petras, Hayley R.,Shepherd, James J.,Williams, Florence J.
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supporting information
p. 10839 - 10843
(2021/06/21)
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- Discovery and characterization of a novel perylenephotoreductant for the activation of aryl halides
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To develop a photocatalyst with catalytical activity for substrates with low reactivities is always highly desired. Herein, based on the principle of structure–property relationships, we rationally designed the natural product cercosporin, the naturally occurring perylenequinonoid pigment, to develop a novel organic perylenephotoreductant, hexacetyl reduced cercosporin (HARCP), through structural manipulation. Compared with cercosporin, HARCP shows prominent electrochemical and photophysical characteristics with greatly improved photoreductive activity, fluorescence lifetime and fluorescence quantum yield. These properties allowed HARCP as a powerful photoreductant to efficiently realize a series of benchmark reactions, including photoreduction, alkoxylation and hydroxylation to construct C–H and C–O bonds using aryl halides as substrates under mild conditions, all of which have never been achieved by the same photocatalyst. Thus, this study well supports the notion that the principle between structural manipulation and photocatalytic activity is of great significance to design customized photocatalysts for photoredox chemistry.
- Guo, Baodang,Huang, Shuping,Li, Jia,Li, Min,Liu, Xuanzhong,Rao, Yijian,Wu, Yawen,Yin, Huimin,Yuan, Zhenbo,Zhang, Yan
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p. 111 - 120
(2021/06/16)
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- Biocatalytic Cross-Coupling of Aryl Halides with a Genetically Engineered Photosensitizer Artificial Dehalogenase
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Devising artificial photoenzymes for abiological bond-forming reactions is of high synthetic value but also a tremendous challenge. Disclosed herein is the first photobiocatalytic cross-coupling of aryl halides enabled by a designer artificial dehalogenase, which features a genetically encoded benzophenone chromophore and site-specifically modified synthetic NiII(bpy) cofactor with tunable proximity to streamline the dual catalysis. Transient absorption studies suggest the likelihood of energy transfer activation in the elementary organometallic event. This design strategy is viable to significantly expand the catalytic repertoire of artificial photoenzymes for useful organic transformations.
- Fu, Yu,Huang, Jian,Wu, Yuzhou,Liu, Xiaohong,Zhong, Fangrui,Wang, Jiangyun
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supporting information
p. 617 - 622
(2021/02/03)
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- Coordination Polymers as a Functional Material for the Selective Molecular Recognition of Nitroaromatics and ipso-Hydroxylation of Arylboronic Acids
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We report the synthesis and structural characterization of two coordination polymers (CPs), namely; [{Zn(L)(DMF)4} ? 2BF4]α (1) and [{Cd(L)2(Cl)2} ? 2H2O]α (2) (where L=N2,N6-di(pyridin-4-yl)naphthalene-2,6-dicarboxamide). Crystal packing of 1 reveals the existence of channels running along the b- and c-axis filled by the ligated DMF and lattice anions, respectively. Whereas, crystal packing of 2 reveals that the metallacycles of each 1D chain are intercalating into the groove of adjacent metallacycles resulting in the stacking of 1D loop-chains to form a sheet-like architecture. In addition, both 1 and 2 were exploited as multifunctional materials for the detection of nitroaromatic compounds (NACs) as well as a catalyst in the ipso-hydroxylation of aryl/heteroarylboronic acids. Remarkably, 1 and 2 showed high fluorescence stability in an aqueous medium and displayed a maximum 88% and 97% quenching efficiency for 4-NPH, respectively among all the investigated NACs. The mechanistic investigation of NACs recognition suggested that the fluorescence quenching occurred via electron as well as energy transfer process. Furthermore, the ipso-hydroxylation of aryl/heteroarylboronic acids in presence of 1 and 2 gave up to 99% desired product yield within 15 min in our established protocol. In both cases, 1 and 2 are recyclable upto five cycles without any significant loss in their efficiency.
- Bhasin, K. K.,Husain, Ahmad,Kumar, Girijesh,Rani, Pooja
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- Isotruxene-based porous polymers as efficient and recyclable photocatalysts for visible-light induced metal-free oxidative organic transformations
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Two new isotruxene-based porous polymers were prepared and demonstrated to be highly efficient, metal-free heterogeneous photocatalysts for oxidative transformations using air as the mild oxidant under visible-light irradiation. Both catalysts show excellent recyclability. In addition, the reactions can be performed in water, further indicating the greenness of this method. This journal is
- Zhang, Haowen,Zhang, Xiao,Zheng, Ying,Zhou, Cen
-
supporting information
p. 8878 - 8885
(2021/11/27)
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- Building a Pyrazole–Benzothiadiazole–Pyrazole Photosensitizer into Metal–Organic Frameworks for Photocatalytic Aerobic Oxidation
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Charge separation plays a crucial role in regulating photochemical properties and therefore warrants consideration in designing photocatalysts. Metal–organic frameworks (MOFs) are emerging as promising candidates for heterogeneous photocatalysis due to their structural designability and tunability of photon absorption. Herein, we report the design of a pyrazole–benzothiadiazole–pyrazole organic molecule bearing a donor–acceptor–donor conjugated π-system for fast charge separation. Further attempts to integrate such a photosensitizer into MOFs afford a more effective heterogeneous photocatalyst (JNU-204). Under visible-light irradiation, three aerobic oxidation reactions involving different oxygenation pathways were achieved on JNU-204. Recycling experiments were conducted to demonstrate the stability and reusability of JNU-204 as a robust heterogeneous photocatalyst. Furthermore, we illustrate its applications in the facile synthesis of pyrrolo[2,1-a]isoquinoline-containing heterocycles, core skeletons of a family of marine natural products. JNU-204 is an exemplary MOF platform with good photon absorption, suitable band gap, fast charge separation, and extraordinary chemical stability for proceeding with aerobic oxidation reactions under visible-light irradiation.
- Jin, Ji-Kang,Wu, Kun,Liu, Xin-Yi,Huang, Guo-Quan,Huang, Yong-Liang,Luo, Dong,Xie, Mo,Zhao, Yifang,Lu, Weigang,Zhou, Xiao-Ping,He, Jian,Li, Dan
-
supporting information
p. 21340 - 21349
(2021/12/17)
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- A Dual-Function Highly Crystalline Covalent Organic Framework for HCl Sensing and Visible-Light Heterogeneous Photocatalysis
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Covalent organic frameworks (COFs) offer great potential for various advanced applications such as photocatalysis, sensing, and so on because of their fully conjugated, porous, and chemically stable unique structural architecture. In this work, we have designed and developed a truxene-based ultrastable COF (Tx-COF-2) by Schiff-base condensation between 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 5,5,10,10,15,15-hexamethyl-10,15-dihydro-5H-diindeno(1,2-a:1′,2′-c)fluorene-2,7,12-tricarbaldehyde (Tx-CHO) for the first time. The resulting COF possesses excellent crystallinity, permanent porosity, and high Brunauer-Emmett-Teller (BET) surface areas (up to 1137 m2 g-1). The COF was found to be a heterogeneous, recyclable photocatalyst for efficient conversion of arylboronic acids to phenols under visible-light irradiation, an environmentally friendly alternative approach to conventional metal-based photocatalysis. Besides, Tx-COF-2 provides an immediate naked-eye color change (1 s) and fluorescence "turn-on"phenomena upon exposure to HCl. The response is highly sensitive, with an ultralow detection limit of up to 4.5 nmol L-1.
- Addicoat, Matthew A.,Nailwal, Yogendra,Pal, Santanu Kumar,Wonanke, A. D. Dinga
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p. 6595 - 6604
(2021/07/20)
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- Double Insurance of Continuous Band Structure and N-C Layer Induced Prolonging of Carrier Lifetime to Enhance the Long-Wavelength Visible-Light Catalytic Activity of N-Doped In2O3
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Nonmetallic doped metal oxides can be broad in their visible-light-response range. However, the half-filled or isolated impurity state can also be the new recombination center for photogenerated electrons/holes, which seriously influence the photocatalytic activity of the catalyst in the visible-light region. Therefore, how to prolong the photogenerated carrier life of nonmetallic doping metal oxides is the difficult and challenging topic in the field of photocatalysis. In this work, the hexagonal nanosheets assembled by N-doped C (N-C)-coated N-doped In2O3 (N-In2O3) nanoparticles (N-C/N-In2O3 HS) was obtained by simply pyrolyzing the In(2,5-PDC) hexagonal sheets. The N-C/N-In2O3 HS catalyst exhibit good photocatalytic activity and cycle stability in the long-wavelength region of visible light (λ = 520 and 595 nm). The effective utilization of long-wavelength visible light for N-C/N-In2O3 HS was mainly attributed to the acceptor-donor-acceptor compensation mechanism between the oxygen vacancy (VO) and substitutional N-doping (Ns) sites, which made the N-C/N-In2O3 HS possess a continuous band structure, without the half-filled or isolated impurity state in the band gap, and extended its light absorption edge to 733 nm. The compensation mechanism of nitrogen doping on In2O3 can promote the photocatalytic activity under longer-wavelength yellow light (595 nm) irradiation. The N-C layer coated on the N-In2O3 nanoparticles acted as a good acceptor of photogenerated electrons, facilitating the effective spatial separation of photogenerated carriers and extend photogenerated carrier lifetimes. The comparative photocatalytic experiments (N-In2O3 HS and N-C/N-In2O3 HS) show that the presence of N-doped C layer can enhance the photocatalytic efficiency by nearly 10-fold. This double-doping and carbon-coating strategy provided a novel research idea to solve the problem that nonmetal atoms doped metal oxides led to the secondary combination of photogenerated electrons/holes.
- Sun, Liming,He, Xiaoxiao,Zeng, Suyuan,Yuan, Yusheng,Li, Rong,Zhan, Wenwen,Chen, Jinquan,Wang, Xiaojun,Han, Xiguang
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supporting information
p. 1160 - 1171
(2021/01/18)
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- Application of Electron-Rich Covalent Organic Frameworks COF-JLU25 for Photocatalytic Aerobic Oxidative Hydroxylation of Arylboronic Acids to Phenols
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Visible-light-driven organic reactions are environmentally friendly green chemical transformations among which photosynthetic oxidative hydroxylation of arylboronic acids to phenols has attracted increasing research interest during the very recent years. Given the efficiency and reusability of heterogeneous catalysts, COF-JLU25, an electron-rich COF-based photocatalyst constructed by integrating electron-donating blocks 1,3,6,8-tetrakis(4-aminophenyl)pyrene (PyTA) and 4-[4-(4-formylmethyl)-2,5-dimethoxyphenyl] benzaldehyde (TpDA), was selected as a photocatalyst for the oxidative hydroxylation of arylboronic acids. In our studies, COF-JLU25 demonstrated excellent photocatalytic activity with high efficiency, robust reusability, and low catalyst loading, showcasing an application potential of previously underexplored COF-based photocatalyst composed solely of electron-rich units.
- Xiao, Guangjun,Li, Wenqian,Chen, Tao,Hu, Wei-Bo,Yang, Hui,Liu, Yahu A.,Wen, Ke
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supporting information
p. 3986 - 3991
(2021/03/29)
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- Method for preparing alcohol and phenol through aerobic hydroxylation reaction of boric acid derivative in absence of photocatalyst
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The invention discloses a method for preparing alcohol and phenol through aerobic hydroxylation reaction of a boric acid derivative in the absence of a photocatalyst, wherein the boric acid derivativeis aryl boronic acid or alkyl boronic acid, and the corresponding target compounds are respectively a phenol-based compound and an alcohol-based compound. According to the method, by using a boric acid derivative as a reaction substrate, an additive is added under a solvent condition, and a hydroxylation reaction is performed under aerobic and illumination conditions to obtain a corresponding target compound. According to the invention, the new strategy is provided for the synthesis of phenols through aerobic hydroxylation of aryl boronic acid without a photocatalyst; the catalyst-free aerobic hydroxylation method for photocatalysis of aryl boronic acid or alkyl boronic acid by using triethylamine as an additive is firstly disclosed; and the new method has advantages of photocatalyst-freecondition, wide substrate range and good functional group compatibility.
- -
-
Paragraph 0025-0028; 0030-0032
(2020/01/25)
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- Method for preparing paraben
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The invention discloses a method for preparing paraben. The method comprises the following steps: adding p-hydroxybenzoic acid (Amol), an alcohol (Bmol) and a benzimidazole ionic liquid (Cmol) into adry three-neck flask, slowly heating, carrying out reflux reaction, and carrying out TLC monitoring until reaction is finished; carrying out reduced pressure distillation to remove a solvent, washingresidues with ethyl acetate, carrying out suction filtration, and carrying out spin-drying on an obtained filtrate to obtain paraben. The yield can reach 90% or above; an obtained filter cake is the benzimidazole ionic liquid and can be recycled; the ratio of A to B to C is 1: 5: (0.2-0.5). The method provided by the invention has the advantages that the catalyst can be recycled, green and environment-friendly effects are realized, the cost is reduced, and the method is an efficient method for synthesizing paraben.
- -
-
Paragraph 0021-0024; 0046
(2020/03/25)
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- Synthesis of Some Aromatic and Aliphatic Esters Using WO3/ZrO2 Solid Acid Catalyst under Solvent Free Conditions
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A simple method is delineated for the synthesis of substituted ester products in superior yields by esterification reaction under solvent unbound condition using tungsten upgraded ZrO2 solid acid catalyst at 353 K. The WO3/ZrO2 catalyst has been prepared by using impregnation method followed by calcination at 923 K over a period of 6 h in air atmosphere. SEM, XRD, FTIR, and BET surface area techniques were used to categorize this catalyst. Zirconia has both acidic and basic possessions which can be changed by incorporating suitable promoter atom like tungsten which in turn increases the surface area thereby enhancing the surface acidity. Impregnation of W6+ ions exhibits a strong influence on phase modification of zirconia from thermodynamically solid monoclinic to metastable tetragonal phase. Amalgamation of promoter W6+ will stabilize tetragonal phase which is active in catalyzing reactions. In esterification reaction WO3/ZrO2 catalyst was found to be stable, efficient and environmental friendly, effortlessly recovered by filtration, excellent yield of product and can be reusable efficiently.
- Guguloth, Vijaya Charan,Battu, Satyanarayana
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p. 2153 - 2157
(2020/09/16)
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- Novel Benzothiazole Ionic Liquids as Catalysts for the Synthesis of Parabens
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Abstract: A simple and green approach to the esterification of p-hydroxybenzoic acid and aliphatic alcohols to obtain parabens was developed. First, two novel benzothiazole ionic liquids [HBth]H2PW12O40 (IL1) and [HBth]H4PMo12O41 (IL2) were synthesized with benzothiazole and heteropolyacids as starting materials. The synthesized ionic liquids were characterized by FTIR spectroscopy, TGA, PXRD analysis, and SEM. The application of IL1 and IL2 as catalysts for the synthesis of parabens was explored. The results showed that the ILs had a high catalytic activity in the synthesis of parabens, and, at the same time, they could be easily recovered and reused five times without loss of activity.
- Liu, B.,Liu, Y.,Sun, J.,Yin, D.
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p. 1476 - 1483
(2020/10/02)
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- Proline ionic liquid and method for catalyzing synthesis of paraben by proline ionic liquid
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The invention discloses proline ionic liquid and a method for catalyzing synthesis of paraben by the proline ionic liquid. The preparation method comprises the following steps: adding N-butylbenzimidazole, a solvent and proline into a dry three-neck flask, carrying out reflux reaction until the reaction is complete (monitored by TLC), evaporating to remove the solvent to obtain a faint yellow oilyliquid, namely the proline ionic liquid, adding p-hydroxybenzoic acid, alcohol and a proline ionic liquid into a dry three-necked bottle, heating to reflux reaction, monitoring by TLC until the reaction is finished, evaporating under reduced pressure to remove the solvent, extracting residues with diethyl ether, evaporating the diethyl ether phase to remove the solvent to obtain the methylparabenwith the yield of 88% or above, wherein the remainder is the ionic liquid, and carrying out washing and drying so that the product can be recycled for many times. The method disclosed by the invention is efficient, environment-friendly and safe, the catalyst can be recycled, the cost is reduced, the requirement on equipment is low, and the method is an efficient method for synthesizing paraben.
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Paragraph 0043-0046
(2020/09/16)
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- Preparation method for p-hydroxybenzonitrile
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The invention relates to the technical field of organic synthesis, specifically to a preparation method for p-hydroxybenzonitrile. The preparation method for the p-hydroxybenzonitrile comprises the following step: allowing p-hydroxybenzamide to react in a solvent under the action of a palladium catalyst, wherein the solvent comprises acetonitrile and water. According to the invention, the acetonitrile is used as a dehydrating agent; a palladium-loaded catalyst is used for catalyzing the reaction; the reaction conditions are mild; and the yield is high. Meanwhile, the acetonitrile is used as the dehydrating agent and the solvent; and a byproduct namely acetamide generated by hydrolysis of acetonitrile is an important product and can be used for production applications, so the additional value is increased.
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-
Paragraph 0060; 0061
(2020/03/12)
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- Design, synthesis, and antimicrobial evaluation of some nifuroxazide analogs against nosocomial infection
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A series of 10 p-substitutedbenzoylmethylene hydrazide derivatives 4a-j were synthesized by protecting carboxylic group of 4-hydroxybenzoic acid using methanol and sulfuric acid than reacting it with hydrazide to form 4-hydroxybenzohydrazide followed by reacting with a variety of aldehydes and evaluated for their activity against nosocomial infection. All the synthesized compounds were characterized by Fourier-transform infrared (FT-IR), 1H nuclear magnetic resonance (NMR), and mass spectral data. The in vitro antimicrobial potential of synthesized compounds was estimated against prominent strains of nosocomial pathogens (Staphylococcus aureus, Escherichia coli, and Aspergillus niger). The antimicrobial evaluation revealed compounds 4b, 4c, 4d, 4e, 4f, and 4j to be the most active compounds of the series with IC50 value for antibacterial in the range 0.39 to 0.75 μM/mL. Furthermore, the in vitro cytotoxic potential of the compounds was appraised by hemolytic assay. The results showed that some of the synthesized compounds exhibited marked activity.
- Agrawal, Ram Kishore,Dighade, Sachin J.,Dwivedi, Deepak K.,Sahu, Adarsh
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- Nickel-catalyzed removal of alkene protecting group of phenols, alcohols via chain walking process
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An efficient nickel-catalyzed removal of alkene protection group under mild condition with high functional group tolerance through chain walking process has been established. Not only phenolic ethers, but also alcoholic ethers can be tolerated with the retention of stereocenter adjacent to hydroxyl group. The new reaction brings the homoallyl group into a start of new type of protecting group.
- Meng, Chenkai,Niu, Haolin,Ning, Juehan,Wu, Wengang,Yi, Jun
-
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- C3N4-Photocatalyzed aerobic oxidative cleavage of CC bonds in alkynes with diazonium salts leading to two different aldehydes or esters in one pot
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A novel photocatalyzed radical addition/oxygen oxidation/cleavage of dioxetane/HAT domino process for cleavage of CC bonds has been described. This protocol used porous graphitic carbon nitrides (p-g-C3N4) as a metal-free recyclable photocatalyst for transformations of alkynes with diazonium salts to give two different aldehydes or esters, which enables the formation of multiple C-O bonds in a single reaction with operational simplicity. This reaction has an excellent substrate scope and gives the desired products in moderate to high yields. In addition, the heterogeneous semiconductor exhibits easy handling and excellent recyclability for at least 6 cycles without any apparent loss of activity. Furthermore, this reaction could be carried out under solar light irradiation and is applicable for the gram scale with satisfactory results.
- Wang, Jingjing,Ni, Bangqing,Niu, Tengfei,Ji, Fei
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p. 8458 - 8464
(2020/12/30)
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- Anchimerically Assisted Selective Cleavage of Acid-Labile Aryl Alkyl Ethers by Aluminum Triiodide and N, N-Dimethylformamide Dimethyl Acetal
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Aluminum triiodide is harnessed by N,N-dimethylformamide dimethyl acetal (DMF-DMA) for the selective cleavage of ethers via neighboring group participation. Various acid-labile functional groups, including carboxylate, allyl, tert-butyldimethylsilyl (TBS), and tert-butoxycarbonyl (Boc), suffer the conditions intact. The method offers an efficient approach to cleaving catechol monoalkyl ethers and to uncovering phenols from acetal-type protecting groups such as methoxymethyl (MOM), methoxyethoxymethyl (MEM), and tetrahydropyranyl (THP) chemoselectively.
- Sang, Dayong,Yue, Huaxin,Zhao, Zhengdong,Yang, Pengtao,Tian, Juan
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p. 6429 - 6440
(2020/07/14)
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- Selective ether bond breaking method of aryl alkyl ether
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The invention discloses a selective aryl alkyl ether cracking method, which comprises that aryl alkyl ether, aluminum iodide and an additive are subjected to a selective ether bond cleavage reaction in an organic solvent at a temperature of -20 DEG C to a reflux temperature to generate phenol and derivatives thereof. The method is mild in condition and simple and convenient to operate, is suitablefor cracking aryl alkyl ether containing o-hydroxyl and o-carbonyl and acetal ether, and can also be used for removing tertiary carbon hydroxyl protecting groups with higher steric hindrance, such astriphenylmethyl, tertiary butyl and the like.
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Paragraph 0243-0247
(2020/09/16)
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- Evidence for Photocatalyst Involvement in Oxidative Additions of Nickel-Catalyzed Carboxylate O-Arylations
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Dual photocatalysis and nickel catalysis can effect cross-coupling under mild conditions, but little is known about the in situ kinetics of this class of reactions. We report a comprehensive kinetic examination of a model carboxylate O-arylation, comparing a state-of-the-art homogeneous photocatalyst (Ir(ppy)3) with a competitive heterogeneous photocatalyst (graphitic carbon nitride). Experimental conditions were adjusted such that the nickel catalytic cycle is saturated with excited photocatalyst. This approach was designed to remove the role of the photocatalyst, by which only the intrinsic behaviors of the nickel catalytic cycles are observed. The two reactions did not display identical kinetics. Ir(ppy)3 deactivates the nickel catalytic cycle and creates more dehalogenated side product. Kinetic data for the reaction using Ir(ppy)3 supports a turnover-limiting reductive elimination. Graphitic carbon nitride gave higher selectivity, even at high photocatalyst-to-nickel ratios. The heterogeneous reaction also showed a rate dependence on aryl halide, indicating that oxidative addition plays a role in rate determination. The results argue against the current mechanistic hypothesis, which states that the photocatalyst is only involved to trigger reductive elimination.
- Madani, Amiera,Malik, Jamal A.,Pieber, Bartholom?us,Seeberger, Peter H.
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supporting information
p. 11042 - 11049
(2020/07/13)
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- Iodine(III)-catalyzed benzylic oxidation by using the (PhIO)n/Al(NO3)3 system
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The first iodine(III)-based procedure for the benzylic oxidation of different arenes is described by using the (PhIO)n/Al(NO3)3 system under catalytic conditions leading to the formation of the corresponding carbonyl derivatives. The method proceeds under mild, operationally simple, room temperature, short reaction times, and open flask conditions. In light of the organocatalysis relevance and the novelty of our protocol, we wish to communicate our initial results of this novel oxidation.
- Yahuaca-Juárez, Berencie,González, Gerardo,Ramírez-Morales, Marco A.,Alba-Betancourt, Calara,Deveze-álvarez, Martha A.,Mendoza-Macías, Claudia L.,Ortiz-Alvarado, Rafael,Juárez-Ornelas, Kevin A.,Solorio-Alvarado, César R.,Maruoka, Keiji
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p. 539 - 548
(2020/01/22)
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- Imidazotetrazines as Weighable Diazomethane Surrogates for Esterifications and Cyclopropanations
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Diazomethane is one of the most versatile reagents in organic synthesis, but its utility is limited by its hazardous nature. Although alternative methods exist to perform the unique chemistry of diazomethane, these suffer from diminished reactivity and/or correspondingly harsher conditions. Herein, we describe the repurposing of imidazotetrazines (such as temozolomide, TMZ, the standard of care for glioblastoma) for use as synthetic precursors of alkyl diazonium reagents. TMZ was employed to conduct esterifications and metal-catalyzed cyclopropanations, and results show that methyl ester formation from a wide variety of substrates is especially efficient and operationally simple. TMZ is a commercially available solid that is non-explosive and non-toxic, and should find broad utility as a replacement for diazomethane.
- Svec, Riley L.,Hergenrother, Paul J.
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supporting information
p. 1857 - 1862
(2019/12/27)
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- Palladium-Catalyzed Hydroxylation of Aryl Halides with Boric Acid
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Boric acid, B(OH)3, is proved to be an efficient hydroxide reagent in converting (hetero)aryl halides to the corresponding phenols with a Pd catalyst under mild conditions. Various phenol products were obtained in good to excellent yields. This transformation tolerates a broad range of functional groups and molecules, including base-sensitive substituents and complicated pharmaceutical (hetero)aryl halide molecules.
- Song, Zhi-Qiang,Wang, Dong-Hui
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supporting information
p. 8470 - 8474
(2020/11/18)
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- Efficient solvent- And temperature-tuned access to aldoxime ethers and phenolic functions by Pd-catalyzed C-O cross-coupling of aldoximes with aryl bromides and bromo-chalcones
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A single method with a functionality switching option was developed for the first time for the Pd-catalyzed C-O cross-coupling of aryl bromides and bromo-chalcones with aldoximes. The ligand tBuXPhos (L2) was found to be an effective supporting ligand for the Pd-catalyzed coupling of aldoximes with bromo coupling partners. The functionality switching from oxime ethers to a phenolic or hydroxy group was driven by solvent or temperature. This method offers the products in good to excellent yields in short reaction times.
- Reeta,Rangarajan,Kaushik, Kumar,Singh, Rishi Pal,Singh, Manjula,Singh, Raj Pal
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supporting information
p. 1326 - 1336
(2020/02/11)
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- Visible light-catalytic hydroxylation of aryl halides with water to phenols by carbon nitride and nickel complex cooperative catalysis
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The efficient conversion of aryl halides to phenols under mild reaction conditions remains a great challenge. Here we demonstrate that a facile and efficient hydroxylation reaction of aryl halides with water could be accomplished through a merger of a heterogeneous organic semiconductor graphitic carbon nitride (g-C3N4) photocatalyst and a homogeneous nickel(ii) bipyridine organometallic catalyst under visible-light irradiation at room temperature. The protocol is tolerant to a wide range of substituted aryl halides, resulting in various phenol products with excellent conversion and selectivity. It is worth noting that the OH group of the resulting phenols originating from water increased the environmental friendliness of the reaction. It is worth noting that among all the previously reported catalysts (even including thermal catalysts with harsh reaction conditions), our Nidabpy/g-C3N4 dual catalytic system demonstrated the highest catalytic activity reported in the shortest reaction time. This remarkable catalytic performance was attributed to the strong interaction between the Nidabpy complex and g-C3N4, which decreased the transfer distance of photogenerated electrons transferring to Ni(ii), accelerating the catalytic cycle. Furthermore, g-C3N4 was easily recovered from the reaction mixture and reused five times, showing the good potential of green hydroxylation reactions for large-scale industrial application.
- Li, Hexing,Liu, Helong,Tong, Min,Wang, Kaixuan,Yang, Yanan,Zhang, Bingyu,Zhang, Fang
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supporting information
p. 7417 - 7423
(2020/11/19)
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- Dual aminoquinolate diarylboron and nickel catalysed metallaphotoredox platform for carbon-oxygen bond construction
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Herein, aminoquinolate diarylboron complexes are utilized as photocatalysts in dual Ni/photoredox catalyzed carbon-oxygen construction reactions. Via this unified metallaphotoredox platform, diverse (hetero)aryl halides can be conveniently coupled with acids, alcohols and water. This method features operational simplicity, broad substrate scope and good compatibility with functional groups. This journal is
- Day, Craig,Jia, Xin,Wei, Lanfeng,Xu, Liang,Zu, Weisai
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supporting information
p. 8273 - 8276
(2020/08/17)
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- Aerobic photooxidative hydroxylation of boronic acids catalyzed by anthraquinone-containing polymeric photosensitizer
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We report herein the synthesis of a polymeric photosensitizer and its application in aerobic photooxidative hydroxylation of boronic acids. The polymeric photosensitizer was synthesized by the condensation of anthraquinone-2-carbonyl chloride (AQ-2-COCl) with poly (2-hydroxyethyl methacrylate) (PHEMA). The photo-oxidative hydroxylation of boronic acids using anthraquinone-containing-poly (2-hydroxyethyl methacrylate) (AQ-PHEMA) was then explored and shown to exhibit high efficiency and broad scope. Moreover, AQ-PHEMA could be easily recovered and reused for more than 20 times without significant loss of the catalytic activity.
- Chen, Yang,Ding, Aishun,Hu, Jianhua
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p. 7927 - 7932
(2020/03/11)
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- Helical Carbenium Ion: A Versatile Organic Photoredox Catalyst for Red-Light-Mediated Reactions
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Red light has the advantages of low energy, less health risks, and high penetration depth through various media. Herein, a helical carbenium ion (N,N′-di-n-propyl-1,13-dimethoxyquinacridinium (nPr-DMQA+) tetrafluoroborate) has been used as an organic photoredox catalyst for photoreductions and photooxidations in the presence of red light (λmax = 640 nm). It has catalyzed red-light-mediated dual transition-metal/photo-redox-catalyzed C-H arylation and intermolecular atom-transfer radical addition through oxidative quenching. Moreover, its potential in photooxidation catalysis has also been demonstrated by successful applications in red-light-induced aerobic oxidative hydroxylation of arylboronic acids and benzylic C(sp3)-H oxygenation through reductive quenching. Thus, a versatile organic photoredox catalyst (helical carbenium ion) for red-light-mediated photoredox reactions has been developed.
- Mei, Liangyong,Veleta, José M.,Gianetti, Thomas L.
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supporting information
p. 12056 - 12061
(2020/08/07)
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- Bimetallic photoredox catalysis: Visible light-promoted aerobic hydroxylation of arylboronic acids with a dirhodium(ii) catalyst
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We report the use of a rhodium(II) dimer in visible light photoredox catalysis for the aerobic oxidation of arylboronic acids to phenols under mild conditions. Spectroscopic and computational studies indicate that the catalyst Rh2(bpy)2(OAc)4 (1) undergoes metal-metal to ligand charge transfer upon visible light irradiation, which is responsible for catalytic activity. Further reactivity studies demonstrate that 1 is a general photoredox catalyst for diverse oxidation reactions.
- Campbell, Michael G.,Chuang, Gary Jing,Liu, Ming-Lun,Miura-Stempel, Emily,Tu, Jing-Wen,Yang, Hsiang-Ming
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p. 2040 - 2047
(2020/03/13)
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- Photocatalytic Molecular Oxygen Activation by Regulating Excitonic Effects in Covalent Organic Frameworks
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Excitonic effects caused by Coulomb interactions between electrons and holes play subtle and significant roles on photocatalysis, yet have been long ignored. Herein, porphyrinic covalent organic frameworks (COFs, specifically DhaTph-M), in the absence or presence of different metals in porphyrin centers, have been shown as ideal models to regulate excitonic effects. Remarkably, the incorporation of Zn2+ in the COF facilitates the conversion of singlet to triplet excitons, whereas the Ni2+ introduction promotes the dissociation of excitons to hot carriers under photoexcitation. Accordingly, the discriminative excitonic behavior of DhaTph-Zn and DhaTph-Ni enables the activation of O2 to 1O2 and O2?-, respectively, under visible light irradiation, resulting in distinctly different activity and selectivity in photocatalytic terpinene oxidation. Benefiting from these results, DhaTph-Ni exhibits excellent photocatalytic activity in O2?-engaged hydroxylation of boronic acid, while DhaTph-Zn possesses superior performance in 1O2-mediated selective oxidation of organic sulfides. This work provides in-depth insights into molecular oxygen activation and opens an avenue to the regulation of excitonic effects based on COFs.
- Qian, Yunyang,Li, Dandan,Han, Yulan,Jiang, Hai-Long
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supporting information
p. 20763 - 20771
(2020/12/23)
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- Visible-light-promoted aerobic oxidative hydroxylation of arylboronic acids in water by hydrophilic organic semiconductor
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A green and sustainable catalytic system was developed based on perylenediimide (PDI) organic semiconductor for the aerobic oxidative hydroxylation of arylboronic acids in aqueous solution with visible light. By using PDI-SN, a hydrophilic organic semiconductor, which can activate oxygen to produce superoxide radicals in aqueous solution, this reaction proceeds under ambient conditions: water as the solvent and air as the oxidant, giving various phenols as products with high yields. In contrast to methods using organic solvents, this novel process has the potential of green industrial application.
- Yu, Kunyi,Zhang, Hanjie,Sheng, Yuqiang,Zhu, Yongfa
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supporting information
(2020/06/23)
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- Synthetic method of Pimavanserin
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The invention belongs to the field of medicine synthesis, and especially relates to a synthetic method of Pimavanserin. According to the synthetic method, 4-hydroxy benzoic acid is taken as a raw material, esterification reaction, alkylation reaction, hydrolysis, acylation reaction, dehydration reduction, and acylation reaction are carried out to obtain an intermediate (9); fluorobenzylamine and N-methyl-4-piperidone are taken as raw materials for reductive amination to obtain intermediate (10); and at last the intermediate (9) and the intermediate (10) are subjected to aminolysis to obtain finished product Pimavanserin. The initial raw materials are cheap and easily available; reaction conditions are mild; no column chromatography is needed; and the yield is relatively high.
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Paragraph 0006; 0034-0036; 0051-0053; 0068-0070
(2019/09/14)
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- A process for preparing Nepal jin zhi method (by machine translation)
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The invention discloses a method for preparing Nepal jin zhi method: in a reaction container by adding of formula choline chloride (Amol) and methanesulfonic acid (Bmol), for 80 °C stirring to complete dissolution shall be low altogether [...]; cooling to room temperature, then added to the hydroxy benzoic acid of formula (Cmol) acrylic (Dmol), slow heating, reflux reaction, TLC monitoring until a reaction is finished (1 - 2 h); reaction liquid-cooled to the room temperature, precipitate solid, filtered, cake of a small amount of washing, get [...], a yield of 90% or more; recycling the filtrate to obtain low altogether [...]. Wherein A: B: C: D is 1: (1 - 4): 1: (1.1 - 1.5). The method of the invention short reaction time, efficiency is high, the catalyst can be recycled, environmental protection, and reducing the cost; to reduce the consumption of the stinging; low requirements on equipment, is an efficient method of synthesizing [...]. (by machine translation)
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Paragraph 0028; 0029; 0030; 0031; 0032; 0033; 0034
(2019/10/02)
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- Method for preparing parabens
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The invention discloses a method for preparing parabens. The method comprises the following steps: adding an appropriate amount of methanol (A) into a reaction container, sequentially adding a benzothiazole ionic liquid (B) and p-hydroxybenzoic acid (C) while stirring, slowly heating the obtained solution to a reflux temperature, and carrying out TLC monitoring until the reaction ends; and distilling off methanol, washing the obtained reaction product with ethyl acetate, carrying out suction filtration (the filter cake is the benzothiazole ionic liquid), carrying out rotary evaporation on thefiltrate, washing the product with water, carrying out suction filtration, and drying the product to obtain colorless crystals (methylparaben) at a yield of 91% or above. A ratio of A:B:C is 1:4:0.15, and a catalyst has a high activity and a good stability, and can be recycled. Additionally, the method also has a high esterification rate of 87%% or above to other parabens (ethylparaben, propylparaben, isopropylparaben, butylparaben and n-dodecyl 4-hydroxybenzoate), and provides a good method for industrial synthesis of parabens.
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Paragraph 0026; 0030-0046; 0048
(2019/07/01)
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- Synthesis, characterisation of new derivatives with mono ring system of 1,2,4-triazole scaffold and their anticancer activities
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In the present study, two important starting materials and 18 new 1,2,4-triazole compounds with mono ring system have been synthesized and characterized. The mono system showed 16 compounds of a Schiff base moiety attached to the triazole ring which was prepared from the corresponding starting material 5(A–B) or piperidinium salt system 6(A–B). All these compounds were characterized using Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy and carbon hydrogen nitrogen (CHN) elemental analysis. The compounds were selected for in vitro anticancer study to test the therapeutic cytotoxic potential against cancer cells. The MTT test was conducted against human breast (MCF-7) and colorectal (HCT-116) cancer cells. Among all the compounds tested, 7A-i demonstrated more pronounced in vitro anticancer effect against MCF-7 and HCT-116 cells with IC50 of 38 and 19.2 μM, respectively, comparable to that of the standard reference drugs, tamoxifen and 5-fluorouracil, respectively. Compound 7A-vi showed a considerable cytotoxic effect with IC50 53 and 41.2 μM against MCF-7 and HCT-116 cells, respectively. Compounds 7A-ii, 7A-iii and 7A-v exhibited moderate cytotoxicity with IC50 68, 91 and 85 μM, respectively against MCF-7 cells and also 59.3, 81.7 and 137.1 μM against HCT-116 cells, respectively. However, all other compounds tested in this study showed poor cytotoxicity against both the cell lines. Cellular morphological analysis revealed that the cytotoxicity induced by the compounds could probably due to autophagy. It can be concluded that 1,2,4-triazole derivatives can be promising therapeutic agents. Further studies will be done to investigate the antitumor efficacy of the 1,2,4-triazole derivatives using suitable preclinical models.
- Slaihim, Mukhlif Mohsin,Al-Suede, Fouad Saleih R.,Khairuddean, Melati,Khadeer Ahamed, Mohamed B.,Shah Abdul Majid, Amin Malik
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- A Structure-Reactivity Relationship of the Tandem Asymmetric Dihydroxylation on a Biologically Relevant Diene: Influence of Remote Stereocenters on Diastereofacial Selectivity
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The Sharpless asymmetric dihydroxylation (AD) finds widespread use in natural product and drug molecule syntheses, in part, due to its efficiency and predictability. However, the tandem AD of dienes is much less studied, but important in complex molecular synthesis. Herein, a biologically relevant tandem AD is reported, and several anomalies are discovered with the accepted model. These include the formation of unpredicted diastereoisomers, with matched and mismatched stereocenters contradicting the Sharpless mnemonic device. From a structural analysis of the tandem AD, we present a strategy to improve asymmetric induction in sterically hindered alkenes using double diastereodifferentiation from a 9-bond distant stereocenter. A theoretical justification for the unpredicted stereoselectivity, accounting for the influence of steric hindrance and pre-installed chirality, is proposed.
- Gill, Daniel M.,Male, Louise,Jones, Alan M.
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supporting information
p. 7568 - 7577
(2019/12/11)
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- Compound as well as preparation method and application thereof as c-Met inhibitor
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The invention provides a compound as well as a preparation method and application thereof as a c-Met inhibitor. The compound has a structure as shown in a formula (X) or an isomer of the compound in the formula (X) or a pharmaceutically acceptable slat of the compound, wherein A is hydrogen or B is shown as the specification or C does not exist or is a benzene ring, and C forms a quinazoline grouptogether with a parent nucleus structure when being the benzene ring; L1 is -NH-CH2- or -O-; L2 does not exist or is -NH-; X is C or N; Y is O or S; R1 is halogen or -NO2; R2 is shown as the specification or is -COR5; R3 is selected from halogen, alkyl and alkoxy; each of R4 and R5 is an independent C3-C6 saturated or unsaturated cycloalkyl, aryl or heteroaryl; and the cycloalkyl, aryl or heteroaryl is substituted or unsubstituted, the substituent group is selected from halogen, nitryl, alkyl and substituent alkyl.
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Paragraph 0184; 0185; 0186
(2019/10/01)
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- Synthesis, crystal structure and biological activity of new phosphoester-p-substituted-methylparabens
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Bis(4-(methoxycarbonyl)phenyl)phosphonate and bis(4-(methoxycarbonyl)phenyl) phosphate were prepared from the reaction of p-hydroxybenzoate with phenyl phosphonic dichloride and with phenyl dichlorophosphate, respectively, in the presence of CuCl as catal
- Serbezeanu,Carja, Ionela-Daniela,Nicolescu,Aflori, Magdalena,Vlad-Bubulac, T?chi??,Butnaru,Damian, Radu-Florin,Dunca, Simona,Shova, Sergiu
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p. 637 - 646
(2019/07/10)
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- METHOD FOR THE SYNTHESIS AND PURIFICATION OF ARYL ACID ESTERS
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The general inventive concepts are directed to the discovery that certain aryl acids can be esterified under particular conditions to provide the resulting ester as a solid that precipitates in good yield from the reaction mixture. The esters may then be isolated and purified with relative ease. Accordingly, a method for the esterification, isolation, and purification of aryl acids is provided.
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Paragraph 0031-0032
(2019/10/17)
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