- Microwave-assisted rapid synthesis of spirooxindole-pyrrolizidine analogues and their activity as anti-amyloidogenic agents
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A library of Sox-pyrrolizidines was rapidly prepared by microwave-assisted, one-pot, three-component, 1,3-dipolar cycloaddition of azomethine ylides from l-proline and isatin, with various β-nitrostyrenes. Nitro-Sox compounds, 4b, 4d and 4e inhibit HEWL amyloid fibril formation by ThT studies with percentages of fluorescence intensity of 55.4, 42.9 and 40.3%, respectively. Further studies with MTT assay, Raman spectroscopy, TEM and molecular docking supported these promising candidates for activity against amyloid misfolding, a phenomenon leading to Alzheimer's disease pathology.
- de Silva, Nilamuni H.,Pyreddy, Suneela,Blanch, Ewan W.,Hügel, Helmut M.,Maniam, Subashani
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supporting information
(2021/07/07)
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- Palladium-Catalyzed Formal (3 + 2) Cycloaddition Reactions of 2-Nitro-1,3-enynes with Vinylaziridines, -epoxides, and -cyclopropanes
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A two-step Pd-catalyzed (3 + 2) cycloaddition/HNO2 elimination reaction sequence has been developed to give novel cyclic 1,3-dien-5-yne systems from Pd-stabilized zwitterionic 1,3-dipoles and 2-nitro-1,3-enyne substrates. The process is highly atom-efficient and tolerates the reaction of 2-vinyloxirane, 1-tosyl-2-vinylaziridine, and diethyl 2-vinylcyclopropane-1,1-dicarboxylate derived 1,3-dipoles with a variety of 2-nitro-1,3-enyne substrates. The stereochemistry of the intermediate (3 + 2) cycloadducts was determined by single crystal X-ray analysis. Furthermore, a selective kinetic elimination of the cycloadduct with an antiperiplanar relationship between the NO2 group and the participating hydrogen was demonstrated, allowing for efficient isolation of a single diastereoisomer of the cycloadduct.
- Drew, Melanie A.,Tague, Andrew J.,Richardson, Christopher,Pyne, Stephen G.,Hyland, Christopher J. T.
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supporting information
p. 4635 - 4639
(2021/06/28)
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- A green metal-free "one-pot" microwave assisted synthesis of 1,4-dihydrochromene triazoles
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The synthesis of several 4-aryl-1,4-dihydrochromene-triazoles was achieved via a metal-free "one-pot"procedure using PEG400 as the sole solvent in an eco-friendly process. Using microwave irradiation, the triazole derivatives were obtained in good yields and short reaction times starting from readily accessible building blocks.
- Alves, Tania M. F.,Jardim, Guilherme A. M.,Ferreira, Marco A. B.
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p. 10336 - 10339
(2021/03/26)
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- Organocatalytic Asymmetric Synthesis of Aza-Spirooxindoles via Michael/Friedel-Crafts Cascade Reaction of 1,3-Nitroenynes and 3-Pyrrolyloxindoles
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An asymmetric [3+3] cyclization of nitroenynes and 3-pyrrolyloxindoles has been realized with a chiral bifunctional squaramide catalyst. This Michael/Friedel-Crafts cascade strategy provides a facile and efficient access to enantioenriched polycyclic aza-spirooxindoles with 32-95% isolated yields and excellent stereocontrol under mild reaction conditions.
- Ni, Qijian,Wang, Xuyang,Zeng, Da,Wu, Qianling,Song, Xiaoxiao
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supporting information
p. 2273 - 2278
(2021/04/05)
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- Skeletally Tunable Seven-Membered-Ring Fused Pyrroles
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We describe a copper-mediated method that enables the synthesis of seven-membered-ring fused pyrroles (7-mrFPs). The protocol proceeds via an in situ spiro-intermediate ring expansion and tolerates a library of 7-mrFP derivatives with a broad range of functional groups in a simple step with tangible parameters and substrate adaptations. These rare 7-mrFPs are now accessible on a millimolar scale, and selected examples exhibit high antioxidant activity.
- Andreou, Dimitrios,Essien, Nsikak B.,Pubill-Ulldemolins, Cristina,Terzidis, Michael A.,Papadopoulos, Athanasios N.,Kostakis, George E.,Lykakis, Ioannis N.
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supporting information
p. 6685 - 6690
(2021/09/11)
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- Ipso Nitration of Aryl Boronic Acids Using Fuming Nitric Acid
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The ipso nitration of aryl boronic acid derivatives has been developed using fuming nitric acid as the nitrating agent. This facile procedure provides efficient and chemoselective access to a variety of aromatic nitro compounds. While several activating agents and nitro sources have been reported in the literature for this synthetically useful transformation, this report demonstrates that these processes likely generate a common active reagent, anhydrous HNO3. Kinetic and mechanistic studies have revealed that the reaction order in HNO3 is >2 and indicate that the ?NO2 radical is the active species.
- Baucom, Kyle D.,Brown, Derek B.,Caille, Seb,Murray, James I.,Quasdorf, Kyle,Silva Elipe, Maria V.
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supporting information
(2021/06/30)
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- A noncovalent hybrid of [Pd(phen)(OAc)2] and st-DNA for the enantioselective hydroamination of β-nitrostyrene with methoxyamine
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We developed a novel Pd-catalysed enantioselective synthesis of C-N bonds using the chiral scaffold of DNA. The non-covalently linked [Pd(phen)(OAc)2] with st-DNA catalysed the Markonicov hydroamination of β-nitrostyrene with methoxyamine for the first time with >75% enantiomeric excess (ee) in an aqueous buffer (pH 7.4) at room temperature.
- Pal, Mrityunjoy,Musib, Dulal,Pal, Maynak,Rana, Gopal,Bag, Gobinda,Dutta, Subrata,Roy, Mithun
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supporting information
p. 5072 - 5076
(2021/06/21)
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- One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes
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β-Nitrostyrenes underwent a Diels-Alder reaction with Danishefsky's diene to afford cyclohexenes together with the corresponding hydrolyzed products, 3-arylated-5-methoxy-4-nitrocyclohexanones. When the reaction was conducted in the presence of water, the cyclohexenes were efficiently hydrolyzed into cyclohexanones. Subsequent aromatization by heating the cyclohexanone with a catalytic amount of iodine in dimethyl sulfoxide gave 3-arylated-4-nitrophenols. The reaction of nitrostyrenes with Danishefsky's diene could be conducted in one pot to directly afford the corresponding nitrophenols. Moreover, a heteroaryl group, e.g., a thienyl group could be introduced into the nitrophenol framework.
- Asahara, Haruyasu,Hiraishi, Minami,Nishiwaki, Nagatoshi
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p. 1830 - 1836
(2020/09/15)
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- Porous Boron Nitride as a Weak Solid Base Catalyst
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Porous boron nitride was synthesized by pyrolysis from boric acid and urea mixed in varying molar ratios. The boron nitride prepared had high surface areas ranging from 376 to 647 m2 g?1 with both microporous and mesoporous structures. The sample prepared with a urea-to-boric acid molar ratio of 5 exhibited the highest pore volume with the highest surface area of mesopores. Boron-K edge X-ray absorption fine structure spectroscopy revealed that the surface structure consisted of BN3 sites along with BN2O, BNO2, and BO3 sites. Fourier transform infrared (FTIR) spectroscopy indicated the formation of amino and hydroxyl groups on the surface. Analysis using color indicator reagents and deuterated chloroform-adsorbed FTIR results indicated that the porous boron nitride had very weak base sites of strength +7.2>H?≥+6.3. Porous boron nitride exhibited a high activity for the nitroaldol reaction with a high selectivity for nitroalkene (>97 %). A good correlation was observed between the catalytic activity of the boron nitride catalysts and their porous structures.
- Nakamura, Shohei,Takagaki, Atsushi,Watanabe, Motonori,Yamada, Kanta,Yoshida, Masaaki,Ishihara, Tatsumi
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p. 6033 - 6039
(2020/10/19)
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- Facile Synthesis of 1,3,5-Triarylbenzenes and 4-Aryl-NH-1,2,3-Triazoles Using Mesoporous Pd-MCM-41 as Reusable Catalyst
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We report mesoporous nano-Pd-MCM-41 catalyzed rapid and efficient synthesis of 1,3,5-triarylbenzenes via de-nitrative cyclotrimerization of β-nitrostyrenes. All the reactions were very fast and high yielding. The Pd-MCM-41 was also very effective in catalyzing de-nitrative [3+2] cycloaddition of β-nitrostyrenes with TMSN3 to synthesize 4-aryl-NH-1,2,3-triazoles. The catalyst was reused at least up to eight times with minimum loss of catalytic activity.
- Saha, Arijit,Wu, Chia-Ming,Peng, Rui,Koodali, Ranjit,Banerjee, Subhash
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p. 104 - 111
(2019/01/04)
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- Triarylimidazo[1,2-a]pyridine-8-carbonitriles: solvent-free synthesis and their anti-cancer evaluation
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In this study, we have presented the synthesis of novel 2,5,7-triarylimidazo[1,2-a]pyridine-8-carbonitriles from 2-amino-4,6-diarlypyridine-3-carbonitrile and nitrostyrene using FeCl3 (20 mol%) as Lewis acid under solvent-free conditions. A library of compounds with diverse substitutions have also been synthesized and screened for in-vitro anti-cancer activity against various cell lines such as A549 (Lung), HCT-116 (Colon), SW-620 (Colon), and MIAPACA (Pancreas).
- Gupta, Annah,Sasan, Sonakshi,Kour, Avneet,Nelofar, Nargis,Manikrao Mondhe, Dilip,Kapoor, Kamal K.
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supporting information
p. 1813 - 1822
(2019/05/15)
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- Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
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Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
- Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
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supporting information
p. 16490 - 16494
(2019/11/03)
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- Cinnamic acid derivative and preparation method and application thereof
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The invention provides a cinnamic acid derivative. The cinnamic acid derivative is of the structure as shown in the formula I. The invention also provides two methods for preparing the cinnamic acid derivative. The two methods depend on a single bond or double bonds in the structure shown in the formula I. The invention further provides a pesticide. The pesticide comprises the cinnamic acid derivative. In addition, the invention provides a sterilization method. The sterilization method includes the step of applying the cinnamic acid derivative or the pesticide to crops. The crops include rice,wheat, fruit trees and vegetables. The low-toxicity, low-residue-content and high-activity environment-friendly cinnamic acid derivative is developed, and the cinnamic acid derivative pesticide can replace traditional high-toxicity and high-residue-content pesticides.
- -
-
Paragraph 0187-0190
(2019/10/22)
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- Synthesis of 3-Nitroisoxazoles via Copper Acetate-Mediated Reaction of Benzaldehydes with Nitromethane
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A copper acetate-mediated reaction of benzaldehydes with nitromethane to synthesis of 3-nitroisoxazoles is reported. A variety of nitro-aryl-disubstituted isoxazole derivatives can be prepared in moderate to good yields with benign functional group tolera
- Fu, Meiqiang,Li, Hui,Su, Miaodong,Cao, Zhongzhong,Liu, Yufeng,Liu, Qiang,Guo, Cancheng
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supporting information
p. 3420 - 3429
(2019/07/22)
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- Magnetically recoverable copper ferrite catalyzed cascade synthesis of 4-Aryl-1H-1,2,3-triazoles under microwave irradiation
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Magnetically active CuFe2O4 catalyzed cascade synthesis of 4-Aryl-1H-1,2,3-triazoles under microwave irradiation starting from aromatic aldehydes, sodium azide and nitromethane has been developed and demonstrated here. The catalyst system needed for the purpose was prepared following a procedure by A. Dandiya et al. with a slight modification and was characterized using FT-IR, XRD, SEM-EDX and TEM analysis. The most notable advantage of the developed methodology is the excellent time economy to carry out the transformation. Other features include simple operating procedure, wide substrate coverage and easy recovery of the catalyst. Reusability of the catalyst has been tested and found to be very satisfactory up to sixth cycle without significant loss in efficiency. All the synthesized compounds have been characterized using FTIR, 1H & 13CNMR spectroscopy, HRMS.
- Bhuyan, Pubanita,Bhorali, Pratiksha,Islam, Imdadul,Bhuyan, Amar Jyoti,Saikia, Lakhinath
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p. 1587 - 1591
(2018/03/29)
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- Base-catalyzed reactions enhanced by solid acids: Amine-catalyzed nitroaldol (Henry) reactions enhanced by silica gel or mesoporous silica SBA-15
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The reactions of various aldehydes with CH3NO2 catalyzed by Et3N, n-C6H13NH2, and Me2N(CH2)2NH2 were accelerated by the addition of silica gel to give aromatic (aliphatic) β-nitroalcohols, aromatic nitroalkenes, and aromatic 1,3-dinitroalkanes, respectively. Mesoporous silica SBA-15 showed higher activity than silica gel for the synthesis of aromatic nitroalkenes by the reactions of the corresponding aldehydes with CH3NO2 catalyzed by n-C6H13NH2.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
-
supporting information
p. 392 - 396
(2017/12/28)
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- Identification of (1S,4S)-2,5-diazabicyclo[2.2.1]heptane-dithiocarbamate-nitrostyrene hybrid as potent antiproliferative and apoptotic inducing agent against cervical cancer cell lines
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The present study seeks to describe the design and synthesis of six new Michael adducts of (1S,4S)-2,5-diazabicyclo[2.2.1]heptane-dithiocarbamate with nitrostyrenes and their in vitro antiproliferative activity against human cervical cancer cell lines [HeLa (HPV 18 positive), CaSki (HPV 16 positive) and ViBo (HPV negative) cervical cancer cell lines]. Virtual screening of the physicochemical properties of all compounds have also been presented. All the compounds exploited significant antiproliferative activity on the three cervical cancer cell lines. Compound 8a was found to be most potent, displaying in vitro antiproliferative activity against HeLa, CaSki and ViBo cervical cancer cell lines superior to Cisplatin and Paclitaxel with IC50 values 0.99 ± 0.007, 2.36 ± 0.016 and 0.73 ± 0.002 μM respectively. In addition, compound 8a did not trigger the necrosis cell death to the test cancer cell lines. Further mechanistic study revealed that compound 8a could inhibit the cancer cell proliferation by inducing apoptosis through caspase-3 activation. Moreover, cell cycle analysis indicated that compound 8a could arrest the cell cycle at the G1 phase for HeLa and CaSki cancer cells. At the predetermined IC50 values on cancer cells, compound 8a did not induce any necrotic (cytotoxic) death to the normal human lymphocytes. In the present design, (1S,4S)-2,5-diazabicyclo[2.2.1]heptane system was found to be superior than the piperazine counterpart 11.
- Laskar, Sujay,Sánchez-Sánchez, Luis,Flores, Sebastián M.,López-Mu?oz, Hugo,Escobar-Sánchez, María L.,López-Ortiz, Manuel,Hernández-Rodríguez, Marcos,Regla, Ignacio
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p. 621 - 635
(2018/02/09)
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- Mechanistic Studies on the Michael Addition of Amines and Hydrazines to Nitrostyrenes: Nitroalkane Elimination via a Retro-aza-Henry-Type Process
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In this article we report on the mechanistic studies of the Michael addition of amines and hydrazines to nitrostyrenes. Under the present conditions, the corresponding N-alkyl/aryl substituted benzyl imines and N-methyl/phenyl substituted benzyl hydrazones were observed via a retro-aza-Henry-type process. By combining organic synthesis and characterization experiments with computational chemistry calculations, we reveal that this reaction proceeds via a protic solvent-mediated mechanism. Experiments in deuterated methanol CD3OD reveal the synthesis and isolation of the corresponding deuterated intermediated Michael adduct, results that support the proposed slovent-mediated pathway. From the synthetic point of view, the reaction occurs under mild, noncatalytic conditions and can be used as a useful platform to yield the biologically important N-methyl pyrazoles in a one-pot manner, simple starting with the corresponding nitrostyrenes and the methylhydrazine.
- Kallitsakis, Michael G.,Tancini, Peter D.,Dixit, Mudit,Mpourmpakis, Giannis,Lykakis, Ioannis N.
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supporting information
p. 1176 - 1184
(2018/02/09)
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- Squaramide-Linked Chloramphenicol Base Hybrid Catalysts for the Asymmetric Michael Addition of 2,3-Dihydrobenzofuran-2-carboxylates to Nitroolefins
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An array of hybrid catalysts incorporating a chloramphenicol base moiety linked to another chiral scaffold through a squaramide linker were developed and successfully used in the Michael addition of 2,3-dihydrobenzofuran-2-carboxylates to nitroolefins. Control experiments suggested that the hybrid catalysts were more reactive than nonhybridized bifunctional catalysts, and matching of the chirality between the two scaffolds was crucial for high reactivity and stereoselectivity. These hybrid organocatalysts could be used with a variety of substrates. At a 0.5 mol-% catalyst loading, a range of 2,3-dihydrobenzofuran-2-carboxylates derivatives bearing quaternary and tertiary stereogenic centers were obtained in high yields (up to 98 %) with excellent enantioselectivities (up to 99 % ee) and moderate diastereoselectivities (up to 8:92 dr).
- Yan, Linjie,Huang, Guanxin,Wang, Haifeng,Xiong, Fangjun,Peng, Haihui,Chen, Fener
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supporting information
p. 99 - 103
(2018/01/17)
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- Copper-Promoted Regioselective Synthesis of Polysubstituted Pyrroles from Aldehydes, Amines, and Nitroalkenes via 1,2-Phenyl/Alkyl Migration
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The facile copper-catalyzed synthesis of polysubstituted pyrroles from aldehydes, amines, and β-nitroalkenes is reported. Remarkably, the use of α-methyl-substituted aldehydes provides efficient access to a series of tetra- and pentasubstituted pyrroles via an overwhelming 1,2-phenyl/alkyl migration. The present methodology is also accessible to non α-substituted aldehydes, yielding the corresponding trisubstituted pyrroles. On the contrary, the use of ketones, in place of aldehydes, does not promote the organic transformation, signifying the necessity of α-substituted aldehydes. The reaction proceeds under mild catalytic conditions with low catalyst loading (0.3-1 mol %), a broad scope, very good functional-group tolerance, and high yields and can be easily scaled up to more than 3 mmol of product, thus highlighting a useful synthetic application of the present catalytic protocol. Based on formal kinetic studies, a possible radical pathway is proposed that involves the formation of an allylic nitrogen radical intermediate, which in turn reacts with the nitroalkene to yield the desired pyrrole framework via a radical 1,2-phenyl or alkyl migration.
- Andreou, Dimitrios,Kallitsakis, Michael G.,Loukopoulos, Edward,Gabriel, Catherine,Kostakis, George E.,Lykakis, Ioannis N.
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p. 2104 - 2113
(2018/02/23)
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- Sulfonation of carbonized xylan-type hemicellulose: A renewable and effective biomass-based biocatalyst for the synthesis of O- and N-heterocycles
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The application of biomass-based carbonaceous solid acids in catalysis is attracting increasing attention in the field of chemistry. In this study, a heterogeneous carbon-based solid acid biocatalyst (CXH-SO3H) with regular spherical structure was synthesized from xylan-type hemicellulose (XH) by a simple two-step method. The catalyst was successfully applied in the synthesis of O- and N-heterocycles with yields of 80-99% and 60-97%, respectively. In view of environment and economy, CXH-SO3H shows the merits of environmental friendliness, easy operation, simple work-up, excellent yields, and the avoidance of use of organic solvents and expensive catalysts. Moreover, the as-synthesized solid acid catalyst could be used for several cycles without significant loss in its catalytic activity. The results of FT-IR, XRD, and SEM showed that no distinct differences in physico-chemical structures of CXH-SO3H were observed. Thus, the eco-friendly CXH-SO3H catalyst is a promising candidate for green synthesis of O- and N-heterocycles from low-cost feed-stocks and has good prospect in partially substituting commercially available solid and liquid acid catalysts and precious metal catalysts.
- Ma, Jiliang,Peng, Xinwen,Zhong, Linxin,Sun, Runcang
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supporting information
p. 9140 - 9150
(2018/06/11)
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- Synthesis of Benzo[4,5]imidazo[2,1-b]thiazole by Copper(II)-Catalyzed Thioamination of Nitroalkene with 1H-Benzo[d]imidazole-2-thiol
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A Copper(II)-catalyzed thioamination of β-nitroalkene with 1H-benzo[d]imidazole-2-thiol has been developed for the synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives. A variety of N-fused benzoimidazothiazole derivatives are obtained in high yields through successive C?N and C?S bond formations. This protocol is also applicable to β-substituted β-nitroalkenes to afford 2,3-disubstituted benzoimidazothiazoles. (Figure presented.).
- Jana, Sourav,Chakraborty, Amrita,Shirinian, Valerii Z.,Hajra, Alakananda
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supporting information
p. 2402 - 2408
(2018/05/08)
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- Method for synthesizing nitroolefin compound
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The invention relates to a method for synthesizing an organic compound. The method is used for solving the problem of current synthesis of nitroolefin compounds that reaction byproducts are numerous,raw materials are expensive, and some methods are relatively troublesome in aftertreatment. The invention provides a method for preparing a nitroolefin compound. The nitroolefin compound is prepared through subjecting a cinnamyl aldehyde compound, which serves as a starting material, to a reaction with a nitrate and a solvent for 1 to 24 hours at the temperature of 25 DEG C to 150 DEG C. A methodfor direct nitration by using a cheap nitrate is achieved. The method is a new route for synthesizing the nitroolefin compound.
- -
-
Paragraph 0058-0060
(2018/03/26)
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- Direct synthesis and application of bridged diamino-functionalized periodic mesoporous organosilicas with high nitrogen contents
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Bridged diamino-functionalized periodic mesoporous organosilicas [BD-PMO(Et), Et = ethyl] materials were synthesized directly by co-condensation of 2-bis (triethoxysilyl)ethane (BTEE) and 1,4-bis[3-(tirmethoxysilyl)-propyl]ethylenediamino (BTMSEN) under acidic conditions with pluronic triblock copolymer P123 as a template. The nitrogen content in BD-PMO(Et) could be adjusted up to 40% without disturbing the ordered mesoporous structure. These materials were proved to be effective heterogeneous catalysts for the liquid-phase reactions such as Knoevenagel and Henry condensations as well as in the intermolecular cross-double-Michael addition reaction between α-methyl-β-nitrostyrene and α, β-unsaturated ketone. They exhibited comparable catalytic activities with homogeneous catalyst piperazine and can be reused for several times without any negative environmental impact.
- Zhu, Feng-Xia,Zhao, Pu-Su,Sun, Xiao-Jun,An, Li-Tao,Deng, Yong,Wu, Jia-Min
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-
- Design, synthesis and molecular docking study of novel pyrrole-based α-amylase and α-glucosidase inhibitors
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Abstract: In an effort to design and synthesize a new class of α-glucosidase and α-amylase inhibitors, we have synthesized novel pyrrole based molecules using molecular hybridization approach. These novel analogs were synthesized by the novel methodology developed in our lab which comprises of the multi-component direct synthesis route using hypervalent iodine reagent. The compounds were characterized by infrared, 1H nuclear magnetic resonance (NMR), 13C NMR and Mass Spectroscopy. These compounds were screened for their α-amylase and α- glucosidase activity. They showed a varying degree of inhibition with IC50 values ranging between 0.4 to 4.14 μmol/mL and 0.8 to 4.14 μmol/mL for α-amylase and α-glucosidase respectively. Compounds 3, 7, 12, and 18 showed excellent activity as compared to standard acarbose. This has identified a new class of α-amylase and α-glucosidase inhibitor which can be further developed as antihyperglycemic agents. The molecular docking analysis was carried out to better understand of interaction between α-amylase and α-glucosidase target and inhibitors in this series. We also generated a homology model for human α-glucosidase enzyme and identified the key residues at the binding site. The outcome of the study could be used for the rational design of potent and selective α-amylase and α-glucosidase inhibitors, respectively. Graphical abstract: [InlineMediaObject not available: see fulltext.].
- Jadhav, Nikhil C.,Pahelkar, Akshata R.,Desai, Neha V.,Telvekar, Vikas N.
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p. 2675 - 2691
(2017/10/05)
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- Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins
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Catalyst-free sulfa-Michael addition of pyrimidine-2-thiol to nitroolefins is described. A series of 2-((2-nitro-1-arylethyl)thio)pyrimidines were efficiently synthesized. The protocol has advantages of wide range of substituents tolerance, no catalyst, additives and bases, mild condition, and high yield. The method can also extend to gram scale.
- Li, Zheng,Song, Geyang,He, Jiaojiao,Du, Yan,Yang, Jingya
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p. 686 - 698
(2017/09/06)
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- Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine-Functionalized Metal–Organic Frameworks
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Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal–organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2, Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2. Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
- Li, Xinle,Zhang, Biying,Tang, Linlin,Goh, Tian Wei,Qi, Shuyan,Volkov, Alexander,Pei, Yuchen,Qi, Zhiyuan,Tsung, Chia-Kuang,Stanley, Levi,Huang, Wenyu
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supporting information
p. 16371 - 16375
(2017/11/28)
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- An Asymmetric Vinylogous Michael Cascade of Silyl Glyoximide, Vinyl Grignard, and Nitroalkenes via Long Range Stereoinduction
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A diastereoselective auxiliary-mediated vinylation/[1,2]-Brook rearrangement/vinylogous Michael cascade of silyl glyoximide, vinylmagnesium bromide, and nitroalkenes is described. The reaction occurs with complete regio- and diastereocontrol in good yield. The diastereoselectivity is induced by a rare instance of 1,7-chirality transfer that is hypothesized to arise from a trans-multihetero-decalin transition state. (Chemical Equation).
- Boyce, Gregory R.,Johnson, Jeffrey S.
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p. 1712 - 1717
(2016/03/01)
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- Yolk-shell-structured mesoporous silica: A bifunctional catalyst for nitroaldol-Michael one-pot cascade reaction
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Great interest in heterogeneous asymmetric catalysis has focused on obtaining an enantioselective cascade reaction through a controllable active site-isolated heterogeneous catalyst. Herein, we utilize a yolk-shell-structured mesoporous silica and assemble an active site-isolated bifunctional heterogeneous catalyst, where chiral cinchonine-based squaramide molecules are anchored within a silicate channel as an outer shell while amine-functionalities are entrapped onto a silicate yolk as an inner core. Structural analyses and characterizations of the heterogeneous catalyst reveal its well-defined single-site chiral active species within its silicate network. Electron microscopy confirms the yolk-shell-structured mesoporous material. As presented in this study, as a bifunctional heterogeneous catalyst, it enables an efficiently nitroaldol-Michael cascade reaction to conduct the three-component coupling of nitromethane, aldehyde and acetylacetone into various chiral diones with high yields and up to 99% enantioselectivities in a one-pot process. As expected, this active site-isolated catalyst not only enhances the catalytic selectivity of the first-step nitroaldol condensation, but also keeps the enantioselectivity of the second-step Michael addition. Moreover, the heterogeneous catalyst can be also recovered easily and recycled repeatedly, making it an interesting feature in a three-component organic transformation.
- An, Juzeng,Cheng, Tanyu,Xiong, Xi,Wu, Liang,Han, Bin,Liu, Guohua
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p. 5714 - 5720
(2016/07/21)
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- Palladium(II)-catalyzed C-C and C-O bond formation for the synthesis of C1-benzoyl isoquinolines from isoquinoline: N -oxides and nitroalkenes
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C1-Benzoyl isoquinolines can be generated via a palladium(ii)-catalyzed C-C and C-O coupling of isoquinoline N-oxides with aromatic nitroalkenes. The reaction proceeds through remote C-H bond activation and subsequent intramolecular oxygen atom transfer (OAT). In this reaction, the N-O bond was designed as a directing group in the C-H bond activation as well as the source of an oxygen atom.
- Li, Jiu-Ling,Li, Wei-Ze,Wang, Ying-Chun,Ren, Qiu,Wang, Heng-Shan,Pan, Ying-Ming
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supporting information
p. 10028 - 10031
(2016/08/15)
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- Synthesis of pyrimidine-2,4,6-trione derivatives: Anti-oxidant, anti-cancer, α-glucosidase, β-glucuronidase inhibition and their molecular docking studies
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This paper describes a facile protocol, efficient, and environmentally benign for the synthesis a series of barbiturate acid substituted at C5 position 3a–o. The desired compounds subjected in vitro for different set of bioassays including against anti-oxidant (DPPH and super oxide scavenger assays), anti-cancer, α-glucosidase and β-glucuronidase inhibitions. Compound 3m (IC50?=?22.9?±?0.5?μM) found to be potent α-glucosidase enzyme inhibitors and showed more activity than standard acarbose (IC50?=?841?±?1.73?μM). Compound 3f (IC50?=?86.9?±?4.33?μM) found to be moderate β-Glucuronidase enzyme inhibitors and showed activity comparatively less than the standard D-saccharic acid 1,4-lactone (IC50?=?45.75?±?2.16?μM). Furthermore, in sillico investigation was carried out to investigate bonding mode of barbiturate acid derivatives.
- Barakat, Assem,Islam, Mohammad Shahidul,Al-Majid, Abdullah Mohammed,Ghabbour, Hazem A.,Yousuf, Sammer,Ashraf, Mahwish,Shaikh, Nimra Naveed,Iqbal Choudhary,Khalil, Ruqaiya,Ul-Haq, Zaheer
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supporting information
p. 72 - 79
(2016/07/26)
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- Zeolite Y-assisted nitration of aromatic and heterocyclic compounds and decarboxylative nitration of α,β-unsaturated acids under non-conventional conditions
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Zeolite Y was found to be an efficient catalyst for a facile nitration of aromatic compounds with acetonitrile as the solvent in the presence of small amounts of HNO3 at room temperature. The reactions afforded mono-nitro derivatives of aromatic compounds in about three hours under stirred conditions with high yields and regioselectivity. The reaction times drastically reduced to about 20 min under sonication and to about 20 s under microwave irradiation. Zeolite is recovered after completion of the reaction and recycled for three to four times without any problem. The approach is particularly appropriate for the conversion of unsaturated cinnamic acids into nitrostyrenes.
- Sudhakar Chary,Rajanna,Krishnaiah,Srinivas
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p. 1430 - 1434
(2016/03/08)
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- Ethylenediamine-functionalized magnetic Fe3O4@SiO2 nanoparticles: cooperative trifunctional catalysis for selective synthesis of nitroalkenes
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A magnetically separable trifunctional nanocatalyst Fe3O4@SiO2-NH2 was synthesized and characterized by TEM, FT-IR, XRD, TGA, and EA. The designed nanocatalyst was found to be highly active for selective synthesis of nitroalkenes with nitromethane and aromatic aldehyde through cooperative trifunctional catalysis of primary amine, secondary amine and Si-OH groups on the surface of the catalyst. Under the optimized conditions, various representative substrates were extended to obtain the corresponding products in moderate or excellent yields. After the reaction, the trifunctional nanocatalyst was easily recovered and recycled by applying an external magnet. In addition, a possible cooperative trifunctional catalysis mechanism was also proposed.
- Xue, Fengjun,Dong, Yahao,Hu, Peibo,Deng, Yanan,Wei, Yuping
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p. 73684 - 73691
(2015/09/15)
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- (1R,2R)-(+)-(1,2)-DPEN-Bonded Sulfonic Acid Resin: A Trifunctional Heterogeneous Catalyst for Asymmetric Michael Additions of Acetone to Nitroolefins
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Based on (1R,2R)-(+)-(1,2)-DPEN skeleton, a series of primary amine-sulfamide bifunctional catalysts were synthesized, which exhibited excellent catalytic performance in the Michael addition of acetone to β-nitrostyrene. Therefore, a trifunctional heterogeneous catalyst was designed and prepared by simple N-sulfonyl reaction of (1R,2R)-(+)-(1,2)-DPEN and sulfonyl chloride resin. It was employed for the aforementioned addition without any additive and satisfactory results (80.5% conversion; 84.3% ee) were obtained. Meanwhile, the structural and textural properties of the catalyst were characterized by infrared spectroscopy (FT-IR), elemental analysis, SEM, and N2 adsorption and desorption experiments. Finally, the generality of the catalyst was investigated.
- Zhang, Chao,Li, Jing,Tian, Jun,Fang, Wangwang,Li, Yang,Chen, Ligong,Yan, Xilong
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supporting information
p. 1248 - 1258
(2015/03/30)
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- Iodine catalyzed one-pot synthesis of highly substituted N-methyl pyrroles via [3 + 2] annulation and their in vitro evaluation as antibacterial agents
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A new class of highly substituted pyrroles have been synthesized via a simple, fast, and efficient method using environmentally friendly iodine catalyzed [3 + 2] annulation. N-Methyl-N-[(E)-1-(methylsulfanyl)-2-nitro-1-ethenyl]amine (NMSM) 1 and β-nitrostyrenes 3 underwent cycloaddition to afford the desired products 4 in excellent yields under solvent and metal free conditions. All the pyrrole derivatives were evaluated for their in vitro anti-bacterial activity. Among the synthesized pyrrole derivatives, 4b, 4c, 4e, 4g, 4i, 4j, 4l, 4m and 4n displayed good inhibitory properties against a panel of Gram positive and negative infectious pathogens.
- Balachandra, Biguvu,Shanmugam, Sivakumar,Muneeswaran, Thillaichidambaram,Ramakritinan, Muthiah
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p. 64781 - 64789
(2015/08/18)
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- Diastereoselective synthesis of polysubstituted cyclopentanols and cyclopentenes containing stereogenic centers via domino Michael/cyclization reaction
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A highly efficient domino Michael/cyclization reaction was developed for the synthesis of cyclopentanols and cyclopentenes with four and three stereogenic centers that were generated in one-pot reaction conditions with high diastereoselectivity. The reactions proceeded through a one-pot three-component reaction of β-nitrostyrenes, malononitrile and phenacyl bromide derivatives in basic media at room temperature.
- Ahadi,Naghdiani,Balalaie,Rominger
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p. 6860 - 6866
(2015/08/24)
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- Ultrasonically Assisted Rate Enhancements in Trichloroisocyanuric Acid/DMF/NaNO2 Triggered Nitration of Aromatic Compounds and Decarboxylative Nitration of α,β-Unsaturated Acids
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An efficient and safe method for nitration of aromatic compounds and decarboxylative nitration of α,β-unsaturated acids was developed using trichloroisocyanuric acid (TCICA)/dimethylformamide (DMF) in the presence of NaNO2. The reaction times of conventional protocol reduced from 8-10 h to 1.0-1.5 h (60-90 min) under sonication, even though the yields are comparable under both the conditions.
- Kumar, Mukka Satish,Rajanna, Kamatala Chinna,Venkateswarlu, Marri,Venkanna, Purugula,Saiprakash, Pondichery Kuppuswamy
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p. 2251 - 2258
(2015/09/22)
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- Stereoselective reaction of 2-carboxythioesters-1,3-dithiane with nitroalkenes: An organocatalytic strategy for the asymmetric addition of a glyoxylate anion equivalent
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An efficient organocatalytic methodology has been developed to perform the stereoselective addition of 2-carboxythioesters-1,3-dithiane to nitroalkenes. Under mild reaction conditions γ-nitro-β-aryl-α-keto esters with up to 92% ee were obtained, realizing a formal catalytic stereoselective conjugate addition of the glyoxylate anion synthon. The reaction products are versatile starting materials for further synthetic transformations; for example, the simultaneous reduction of the nitro group and removal of the dithiane ring was accomplished, allowing the preparation of a GABAB receptor agonist baclofen.
- Massolo, Elisabetta,Benaglia, Maurizio,Genoni, Andrea,Annunziata, Rita,Celentano, Giuseppe,Gaggero, Nicoletta
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supporting information
p. 5591 - 5596
(2015/05/27)
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- Diaminosilane-functionalized on silicate-stabilised hydrotalcite (MA-HTSi-DA): As potential catalyst for nitro-aldol condensation
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Diaminosilane was introduced into silicate-anion-intercalated hydrotalcite (HT-Si) using a post-synthesis method. The resulting functionalized materials possess surface basicity. The textural properties of the functionalized materials were systematically investigated through powder XRD, FTIR and MAS-NMR studies. The diamine-functionalized materials showed very good catalytic activity for the nitro-aldol condensation of benzaldehyde and nitromethane under solvent-free conditions. The materials showed comparable catalytic activity upon recycling.
- Thangaraj, Baskaran,Jayaraj, Christopher,Srinivasan, Radhakrishnan,Ayyamperumal, Sakthivel
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- 17a-HYDROXYLASE/C17,20-LYASE INHIBITORS
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The present invention provides compounds of Formula (I), or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, A and n are as defined herein. A deuteriated derivative of the compound of Formula (I) is also provided.
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Paragraph 0170; 0171
(2014/03/21)
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- Highly efficient iridium-catalyzed asymmetric hydrogenation of β-acylamino nitroolefins
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The first highly efficient Ir-catalyzed enantioselective hydrogenation of β-acylamino nitroolefins is reported. This reaction provides straightforward access to chiral β-amino nitroalkanes in high yields and excellent enantioselectivities (up to >99.9% ee) catalyzed by an Ir-(R,R)-f-spiroPhos complex. This journal is
- Yan, Qiaozhi,Liu, Man,Kong, Duanyang,Zi, Guofu,Hou, Guohua
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supporting information
p. 12870 - 12872
(2014/12/11)
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- Synthesis, in vitro cytotoxicity and apoptosis inducing study of 2-aryl-3-nitro-2 H -chromene derivatives as potent anti-breast cancer agents
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A series of 2-aryl-3-nitro-2H-chromenes 4a-u were designed as hybrid analogs of flavanone, β-nitrostyrene and nitrovinylstilbene scaffolds. They were synthesized from the reaction of appropriate β-nitrostyrenes and salicylaldehydes in good yields. In vitro cytotoxic activities of compounds 4a-u were tested against breast cancer cell lines including MCF-7, T-47D and MDA-MB-231. Most compounds exhibited good cytotoxic activity against selected cell lines, being more potent than standard drug etoposide. Representatively, 8-methoxy-3-nitro-2-(4-chlorophenyl)-2H-chromene (4l) with IC50 Combining double low line 0.2 μ4M against MCF-7 cells, was 36-times more potent than etoposide. Apoptosis as a mechanism of cell death for selected compounds 4h and 4l was confirmed morphologically by acridine orange/ethidium bromide double staining and TUNEL analysis, as well as caspase-3 activation assay.
- Rahmani-Nezhad, Samira,Safavi, Maliheh,Pordeli, Mahboobeh,Ardestani, Sussan Kabudanian,Khosravani, Leila,Pourshojaei, Yaghoub,Mahdavi, Mohammad,Emami, Saeed,Foroumadi, Alireza,Shafiee, Abbas
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p. 562 - 569
(2015/01/09)
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- A branched domino reaction: Asymmetric organocatalytic two-component four-step synthesis of polyfunctionalized cyclohexene derivatives
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Take two: By employing two equivalents of an aldehyde in an asymmetric organocatalytic domino reaction, the nucleophilic enamine intermediate is also converted into the corresponding iminium species through oxidation with o-iodoxybenzoic acid. Thus, polyfunctionalized cyclohexene derivatives are formed from two simple starting materials in good yields and stereoselectivities (see scheme; Bn=benzyl, EWG=electron-withdrawing group). Copyright
- Zeng, Xiaofei,Ni, Qijian,Raabe, Gerhard,Enders, Dieter
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supporting information
p. 2977 - 2980
(2013/04/11)
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- Urea postmodified in a metal-organic framework as a catalytically active hydrogen-bond-donating heterogeneous catalyst
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New functionally diverse urea-derived MOF hydrogen-bond-donating heterogeneous catalysts were achieved via postsynthetic modification, which exhibit excellent catalytic activity and very broad substrate scopes for the Friedel-Crafts alkylation reactions.
- Dong, Xiao-Wu,Liu, Tao,Hu, Yong-Zhou,Liu, Xin-Yuan,Che, Chi-Ming
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supporting information
p. 7681 - 7683
(2013/09/02)
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- Oxalylchloride/DMF as an efficient reagent for nitration of aromatic compounds and nitro decarboxylation of cinnamic acids in presence of KNO 3 or NaNO2 under conventional and nonconventional conditions
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Nitration of aromatic compounds and cinnamic acids with oxalylchloride/DMF afforded the corresponding nitro derivatives in the presence of KNO3 or NaNO2 under conventional and nonconventional (ultrasonic and microwave) conditions. The present methodology offers several benefits such as excellent yields, simple work-up procedure, and short reaction times. The yields obtained under present methodology are comparable with those obtained from (POCl3/DMF/KNO3 or NaNO2) and (SOCl 2/DMF/KNO3 or NaNO2) systems followed by shorter reaction times. The reaction times of sonication and microwave conditions are very shorter than those of the conventional conditions.
- Kumar, M. Satish,Reddy, K. Rajendar,Rajanna,Venkanna,Krishnaiah
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p. 977 - 983
(2013/06/05)
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- Ultrasonic and microwave-assisted synthesis of β-nitro styrenes and nitro phenols with tertiary butyl nitrite under acid-free conditions
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Tertiary butyl nitrite (TBN) is an acid-free and safe nitrating agent that provides preferentially β-nitrostyrenes with cinnamic acids and corresponding nitro derivatives with phenols in good yields under classical conditions. However, ultrasonic and microwave-assisted reactions reduced the reaction times substantially and enhanced the yields from good to excellent. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Kumar, M. Satish,Rajanna,Reddy, K. Rajendar,Venkateswarlu,Venkanna
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supporting information
p. 2672 - 2677
(2013/07/26)
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- A novel route to organonitrites by Pd-catalyzed cross-coupling of sodium nitrite and potassium organotrifluoroborates
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Microwave irradiated palladium-catalyzed cross-coupling reaction of potassium styryltrifluoroborates and sodium nitrite gives the corresponding styryl nitrites in high yields. Potassium aryltrifluoroborates also furnish aryl nitrites under same reaction condition. This unprecedented cross-coupling is an interesting development and has the potential to lead to new nitration protocols.
- Al-Masum, Mohammad,Saleh, Nabil,Islam, Tasfia
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supporting information
p. 1141 - 1144
(2013/03/28)
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- Asymmetric N-heterocyclic carbene catalyzed addition of enals to nitroalkenes: Controlling stereochemistry via the homoenolate reactivity pathway to access δ-lactams
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An asymmetric intermolecular reaction between enals and nitroalkenes to yield δ-nitroesters has been developed, catalyzed by a novel chiral N-heterocyclic carbene. Key to this work was the development of a catalyst that favors the δ-nitroester pathway over the established Stetter pathway. The reaction proceeds in high stereoselectivity and affords the previously unreported syn diastereomer. We also report an operationally facile two-step, one-pot procedure for the synthesis of δ-lactams.
- White, Nicholas A.,Dirocco, Daniel A.,Rovis, Tomislav
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p. 8504 - 8507
(2013/07/19)
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- 17α-HYDROXYLASE/C17,20-LYASE INHIBITORS
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The present invention provides compounds of Formula (I), or a pharmaceutically acceptable salt thereof, where R1, R2, R3, R4, R5, R6, A and n are as defined herein. A deuteriated derivative of the compound of Formula (I) is also provided.
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Page/Page column 35-36
(2012/04/04)
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