- Cellular AND Gates: Synergistic Recognition to Boost Selective Uptake of Polymeric Nanoassemblies
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The development of nanoparticle-based biomedical applications has been hampered due to undesired off-target effects. Herein, we outline a cellular AND gate to enhance uptake selectivity, in which a nanoassembly–cell interaction is turned on, only in the concurrent presence of two different protein functions, an enzymatic reaction (alkaline phosphatase, ALP) and a ligand–protein (carbonic anhydrase IX, CA IX) binding event. Selective uptake of nanoassemblies was observed in cells that overexpress both of these proteins (unicellular AND gate). Interestingly, selective uptake can also be achieved in CA IX overexpressed cells, when cocultured with ALP overexpressed cells, where the nanoassembly presumably acts as a mediator for cell–cell communication (bicellular AND gate). This logic-gated cellular uptake could find use in applications such as tumor imaging or theranostics.
- Fernandez, Ann,Gao, Jingjing,Thayumanavan, S.,Wu, Peidong,Zhuang, Jiaming
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- Kinetics and Mechanism of Oxidation of L-Threonine in Acid Media by Sodium N-Chloro-p-toluenesulfonamide
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Kinetics of oxidation of L-threonine in the presence of HCl, HClO4, and H2SO4 by chloramine-T (CAT) has been investigated at 35 deg C.The reactions follow identical kinetics in all acids, being first order in CAT, fractional order in substrate and Cl- ion, and of an inverse fractional order in +>.Variation of ionic strength and addition of the reaction product, p-toluenesulfonamide, or the ions SO42- and ClO4- had no effect on the rate.Decrease of dielectric constant of the medium by adding methanol decreased the rate.The solvent isotope effect was studied by using heavy water.The reactions were studied at different temperatures, and activation parameters have been computed.Mechanisms proposed and the derived rate laws are consistent with the observed kinetics.The rate constants predicted by the derived rate laws, as the concentrations of H+ ion, substrate, and Cl- ion change, are in excellent agreement with the observed rate constants, thus further justifying these rate laws and hence the proposed mechanistic schemes.
- Mahadevappa, D. S.,Rangappa, K. S.,Gowda, N. M. M.,Gowda, B. Thimme
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- Synthesis of 8-Alkoxy-5 H-isochromeno[3,4- c]isoquinolines and 1-Alkoxy-4-arylisoquinolin-3-ols through Rh(III)-Catalyzed C-H Functionalization of Benzimidates with 4-Diazoisochroman-3-imines and 4-Diazoisoquinolin-3-ones
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Rh(III)-catalyzed C-H activation/annulation of benzimidates with 4-diazoisochroman-3-imines furnished 8-alkoxy-5H-isochromeno[3,4-c]isoquinolines in moderate to excellent yields with a broad range of substrate scope. The reaction was carried out under mild reaction conditions and could be scaled up with practical usage. Similar reaction between benzimidates and 4-diazoisoquinolin-3-ones provided 1-alkoxy-4-arylisoquinolin-3-ols in excellent yields. Moreover, the synthesized products could be conveniently transformed to the corresponding heterocycles with a 1,8-naphthyridinone or isochromenopyridinone core, which are privileged structures in medicinal chemistry.
- Li, Zhenmin,Lu, Ping,Wang, Yanguang,Xie, Jianwei
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- Kinetics and Mechanism of the Oxidation of Hypophospite with N-Chlorotoluene-p-sulphonamide (Chloramine T) catalysed by Osmium(VIII) in Alkaline Solution
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The kinetics of osmium(VIII)-catalysed oxidation of hypophosphite, H2PO2-, with chloramine T (cat, N-chlorotoluene-p-sulphamide) was studied by estimating the latter iodometrically.The rate law (i) holds for -> = 0.02-0.142, H2PO
- Hussain, Juzar,Mishra, Som Kant,Sharma, Preen Dutt
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- Anisole alkylation with N-arenesulfonylimines of dichloro(phenyl)acetaldehyde and derivatives thereof
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N-[1-4-Methoxyphenyl-2-phenyl-2,2-dichloroethyl]arenesulfonamides are formed in reaction of N-(2-phenyl-2,2-dichloroethylidene)-4-chlorobenzenesulfonamide and N-(2-phenyl-2,2-dichloroethylidene)-4-methylbenzenesulfonamide with anisole catalyzed by boron t
- Drozdova,Mirskova
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- The Reaction of Thiocumulenes with Fulvene
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S-(9-Fluorenylidene)-N-(p-tolylsulfonyl)-sulfimide and bis(p-tolylsulfonyl)sulfur diimide reacted as 1,3-dipoles with fulvenes to form (2+3)cycloadducts.
- Saito, Takao,Musashi, Teruhiko,Motoki, Shinichi
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- Structural, vibrational spectra and normal coordinate analysis for two tautomers of 4(5)-(2′-furyl)-imidazole
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We have synthesized both the 4 and 5 tautomeric forms of 4(5)-(2′-furyl)-imidazole (1) and investigated their molecular vibrations by infrared and Raman spectroscopies as well as by calculation based on the density functional theory (DFT) approach. Examination of the temperature dependence of IR intensity revealed the band characteristics of the 4 and 5 tautomersof(1).Comparisonofexperimentalandcalculatedchemicalshiftsinnucl earmagneticresonance(NMR)spectroscopy was made in order to identify the two tautomeric forms. The assignment of vibrational normal modes was performed, and the forcefieldobtainedreproduced theexperimentalvibrationalwavenumbers with a root mean-squaredeviation (RMSD)value of ca. 13 cm-1 for both tautomers. The natural bond orbital (NBO) study reveals the characteristics of the electronic delocalization of the two tautomeric structures.
- Ledesma,Zinczuk,Gonzalez, J.J. Lopez,Altabef, A. Ben,Brandan
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- Synthesis of cyclic sulfonamides via Pd-catalyzed intramolecular coupling reaction: An expedient approach to polycyclic sultams
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A divergent synthetic approach to polycyclic sultams utilizing intramolecular ligand-free intramolecular coupling reaction is described. Georg Thieme Verlag Stuttgart.
- Majumdar,Mondal, Shovan,De, Nirupam
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- Formation and Isolation of the Disulphide Dication of 1,5-Dithiacyclo-octane in the Reactions of the Corresponding S-Oxide and S-(N-tosylimide) in Concentrated Sulphuric Acid
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The disulphide dication of 1,5-dithiacyclo-octane was generated in the reaction of the corresponding S-oxide and S-(N-tosylimide) with conc.H2SO4 and isolated in crystalline form.
- Furukawa, Naomichi,Kawada, Akira,Kawai, Tsutomu
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- Michael additions of oxygen and sulfur nucleophiles to 3,4-Di-t-butyl-1-[(p-tolyl)sulfonylimino]-1,1-dihydrothiophene. A comparison study with 3,4-Di-t-butylthiophene 1-oxide and 1,1-dioxide
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The reactions of 3,4-di-t-butyl-1-[(p-tolyl)sulfonylimino]-1,1-dihydrothiophene with RONa and RSNa furnished 2-alkoxy-and 2-alkylthio-substituted thiophenes, respectively, through Michael adduct formation. The reaction of 3,4-di-t-butylthiophene 1-oxide with RSNa gave 1,6-Michael adducts, whereas the corresponding reaction of 3,4-di-t-butylthiophene 1,1-dioxide produced a mixture of 1,4-and 1,6-adducts.
- Otani, Takashi,Sugihara, Yoshiaki,Ishii, Akihiko,Nakayama, Juzo
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- Cyclopropyl aziridines: Solvolytic reactions of the N-tosylaziridines of (+)-2-carene and (+)-3-carene
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The N-tosylaziridine 4 of (+)-2-carene 1 was prepared and subjected to solvolytic reactions with weak protic acids. For comparison, the solvolytic reactions of cis-3-carene-N-tosylaziridine 8 were also studied. The solvolyses of 4 were more rapid than those of 8, and both rings were opened in 4, whereas only the aziridine was opened in 8. This leads to the conclusion that the aziridine and cyclopropane rings in 4 can achieve a conjugated transition state.
- Silverberg, Lee J.,Rabb, Javon M.,Reno, Joseph M.,He, Gang
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- Diazabenzo[a]phenoxazone sulphonamides: synthesis, in-silico and in-vitro antimicrobial studies
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The syntheses of new sulphonamide derivatives of 8,10-diazabenzo[a]phenoxazones are reported. The condensation of 4,5-diamino-6-hydroxy-2-mercaptopyrimidine and 2,3-dichloro-1,4-naphthoquinone in a basic medium gave the key functional intermediate, 11-amino-6-chloro-9-mercapto-8,10-diazabenzo[a]phenoxazin-5-one. The conversion of the later compound to its sulphonamide derivatives was achieved via nickel catalyzed cross-coupling Buchwald-Hartwig protocol. Reaction between 11-amino-6-chloro-9-mercapto-8,10-diazabenzo[a]phenoxazin-5-one and various aryl sulphonamides and sulphonyl chlorides furnished eight new mono sulphonamide substituted diazaphenoxazone compounds. Subsequent coupling of mono sulphonamide substituted diazaphenoxazone compounds 5a-d with four different arylsulphonyl chlorides under similar reaction conditions gave the disubstituted derivatives 8a-d. The products were isolated in 74 – 88% yields and characterized by means of Uv-visible, FT-IR, 1H-NMR, 13C-NMR, and Mass spectroscopy. The synthesized compounds were screened for antimicrobial activity against bacterial strains: Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhi and Klebsiella pneumonia, and fungal strains, Aspergillus niger, and Candida albican, using agar-well diffusion method. The activities of the compounds were compared with that of colymycin, which is a strong antibacterial, and antifungal drug, Most of the compounds showed appreciable antimicrobial activities comparable with the activity of colymycin. The in silico study revealed that all the synthesized compounds showed significant binding affinity for both intact and mutated DNA gyrase. Compounds 8a and 5b showed the highest binding affinities of -12.31 and -13.30 kcal/mol for intact and mutated DNA gyrase respectively.
- Ezeokonkwo, Mercy A.,Eze, Cosmas C.,Okafor, Sunday N.,Onoabedje, Efeturi A.,Godwin-Nwakwasi, Evelyn U.,Ibeanu, Fidelia N.
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- Data-Driven Identification of Hydrogen Sulfide Scavengers
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Hydrogen sulfide (H2S) is an important signaling molecule whose up- and down-regulation have specific biological consequences. Although significant advances in H2S up-regulation, by the development of H2S donors, have been achieved in recent years, precise H2S down-regulation is still challenging. The lack of potent/specific inhibitors for H2S-producing enzymes contributes to this problem. We expect the development of H2S scavengers is an alternative approach to address this problem. Since chemical sensors and scavengers of H2S share the same criteria, we constructed a H2S sensor database, which summarizes key parameters of reported sensors. Data-driven analysis led to the selection of 30 potential compounds. Further evaluation of these compounds identified a group of promising scavengers, based on the sulfonyl azide template. The efficiency of these scavengers in in vitro and in vivo experiments was demonstrated.
- Yang, Chun-tao,Wang, Yingying,Marutani, Eizo,Ida, Tomoaki,Ni, Xiang,Xu, Shi,Chen, Wei,Zhang, Hui,Akaike, Takaaki,Ichinose, Fumito,Xian, Ming
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- Base Promoted Three-Component Annulation of 4-Diazoisochroman-3-imines with Dimethylsulfonium Ylides: Synthesis of Highly Functionalized Isochromeno[4,3- c]pyridazines
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A novel method has been developed to synthesize a unique class of highly functionalized isochromeno[4,3-c]pyridazines. This reaction features an intermolecular functionalization of terminal nitrogen atom of diazo group of 4-diazoisochoman-3-imine with two dimethylsulfonium ylide components, followed by a base promoted 6-exo-trig cyclization step. Readily available starting materials, a broad substrate scope, and operationally simple, mild, and catalyst-free reaction conditions are the prominent features of this method.
- Suleman, Muhammad,Xie, Jianwei,Wang, Zaibin,Lu, Ping,Wang, Yanguang
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- Fine-tuning hydroxylamines as single-nitrogen sources for Pd(0)-catalyzed diamination of o-bromo(or chloro)-biaryls
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Transition metal-catalyzed diamination by hydroxylamines is a common approach for making three-membered aziridines, while its use for building the larger N-heterocycles is still underdeveloped. Herein, we report an efficient Pd(0)-catalyzed inter-molecular [4+1] annulation of o-bromo(or chloro)-biaryls with bifunctional secondary hydroxylamines for the one-step assembly of synthetically useful carbazoles. Noteworthily, a linchpin for this domino reaction was the judicious selection of both the amino-sources and Pd(0)-catalysts for enabling the prerequisite oxidative addition of aryl halides to Pd(0)-species in the presence of hydroxylamines with a labile N-O bond. [Figure not available: see fulltext.].
- Bai, Jiaxing,Ding, Pin,Han, Lingbo,Liu, Jingjing,Luan, Xinjun
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- Synthesis, biological evaluation, and docking studies of novel pyrrolo[2,3-b]pyridine derivatives as both ectonucleotide pyrophosphatase/phosphodiesterase inhibitors and antiproliferative agents
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Ecto-nucleotide pyrophosphatases/phosphodiesterases (NPPs) together with nucleoside triphosphate diphosphohydrolases (NTPDases) and alkaline phosphatases (APs) are nucleotidases located at the surface of the cells. NPP1 and NPP3 are important members of NPP family that are known as druggable targets for a number of disorders such as impaired calcification, type 2 diabetes, and cancer. Sulfonylurea derivatives have been reported as antidiabetic and anticancer agents, therefore, we synthesized and investigated series of sulfonylurea derivatives 1a-m possessing pyrrolo[2,3-b]pyridine core as inhibitors of NPP1 and NPP3 isozymes that are over-expressed in cancer and diabetes. The enzymatic evaluation highlighted compound 1a as selective NPP1 inhibitor, however, 1c was observed as the most potent inhibitor of NPP1 with an IC50 value of 0.80 ± 0.04 μM. Compound 1l was found to be the most potent and moderately selective inhibitor of NPP3 (IC50 = 0.55 ± 0.01 μM). Furthermore, in vitro cytotoxicity assays of compounds 1a-m against MCF-7 and HT-29 cancer cell lines exhibited compound 1c (IC50 = 4.70 ± 0.67 μM), and 1h (IC50 = 1.58 ± 0.20 μM) as the most cytotoxic compounds against MCF-7 and HT-29 cancer cell lines, respectively. Both of the investigated compounds showed high degree of selectivity towards cancer cells than normal cells (WI-38). Molecular docking studies of selective and potent enzyme inhibitors revealed promising mode of interactions with important binding sites residues of both isozymes i.e., Thr256, His380, Lys255, Asn277 residues of NPP1 and His329, Thr205, and Leu239 residues of NPP3. In addition, the most potent antiproliferative agent, compound 1h, doesn't produce hypoglycemia as a side effect when injected to mice. This is an additional merit of the promising compound 1h.
- Ullah, Saif,El-Gamal, Mohammed I.,El-Gamal, Randa,Pelletier, Julie,Sévigny, Jean,Shehata, Mahmoud K.,Anbar, Hanan S.,Iqbal, Jamshed
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- Inhibitory Evaluation and Molecular Docking Analysis of Benzenesulfonamides on Carbonic Anhydrase II
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Abstract: Sulfonamides is an important class of compounds, which can be used as carbonic anhydrase inhibitors. Nine different benzenesulfonamide compounds were synthesized, and their inhibitory effects on carbonic anhydrase II were studied by esterase method and molecular docking. The results showed that compounds (IId)–(IIg) with nitro and acetamide groups on the benzene ring exhibited excellent carbonic anhydrase II inhibitory activities. Molecular docking showed that compared with the control inhibitor acetazolamide, the compounds (IId)–(IIg) docked at the carbonic anhydrase II active site and showed higher binding energy and stronger binding ability. The physical and chemical properties of all compounds were studied by Molinspiration, which showed outstanding drug-like properties and ADME properties. Cytotoxicity assay results showed that compounds (IIe) and (IIf) were almost non-toxic to HepG2 and RAW264.7 cells. In conclusion, the compounds (IIe) and (IIf) have a certain application prospect as new inhibitors of carbonic anhydrase II.
- Zhang,Wei,Liu,Wu,Xuan
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p. 261 - 269
(2021/03/23)
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- Synthesis of magnetic chitosan supported metformin-Cu(II) complex as a recyclable catalyst for N-arylation of primary sulfonamides
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The application of chitosan, which has received much attention as a natural polymer and effective support, has many advantages such as biodegradability and biocompatibility. In this study, the immobilization of a copper complex on the magnetic chitosan bearing metformin ligand has been developed through immobilizing structurally defined metformin with long tail of (3-chloropropyl)trimethoxysilane (TMOS). The synthesized Fe3O4-chitosan@metformin-Cu(II) complex (Fe3O4-CS@Met-Cu(II)) was used as an effective, reusable and magnetic catalyst in the N-arylation of different derivatives of primary sulfonamides with arylboronic acids in ethanol. The primary sulfonamides were prepared from the reaction of sulfonyl chlorides with sodium cyanate in water under ultrasonic irradiation. Utilizing a wide variety of substrates in EtOH as a green solvent, high yields of the primary and secondary sulfonamides, easy work-up along with the excellent recovery and reusability of the catalyst, make this process a simple, economic and environmentally benign method. The synthesized Fe3O4-CS@Met-Cu(II) was characterized using various techniques such as XRD (X-ray diffraction), EDS (energy-dispersive X-ray spectroscopy), elemental mapping, TEM (transmission electron microscopy), FESEM (field emission scanning electron microscopy), VSM (vibrating sample magnetometer), ICP-MS (inductively coupled plasma mass spectroscopy), TGA (thermogravimetric analysis) and FT-IR (Fourier-transform infrared spectroscopy) analyses. The catalyst can be recycled and reused 5 times with no considerable loss of catalytic activity.
- Ahmadpoor, Fatemeh,Nasrollahzadeh, Mahmoud,Nezafat, Zahra,Pakzad, Khatereh
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- Unlocking Amides through Selective C–N Bond Cleavage: Allyl Bromide-Mediated Divergent Synthesis of Nitrogen-Containing Functional Groups
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We report a new set of reactions based on the unlocking of amides through simple treatment with allyl bromide, creating a common platform for accessing a diverse range of nitrogen-containing functional groups such as primary amides, sulfonamides, primary amines, N-acyl compounds (esters, thioesters, amides), and N-sulfonyl esters. The method has potential industrial applicability, as demonstrated through gram-scale syntheses in batch and in a continuous flow system.
- Govindan, Karthick,Chen, Nian-Qi,Chuang, Yu-Wei,Lin, Wei-Yu
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p. 9419 - 9424
(2021/11/30)
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- Cyhalofop-containing pesticide composition and application thereof
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The invention discloses a pesticide composition containing cyhalofop-butyl and application thereof, belongs to the technical field of pesticide preparation and comprises 10 - 20 parts of cyhalofop-butyl. Tetramethyl chloride 3-5 parts, synergistic microcapsule 8-13 parts, wetting agent 1.5 - 4.5 parts, dispersing agent 1-3 parts, defoaming agent 0.5 - 1.5 parts and water 40 - 50 parts. When the water in the soil is less, the weed is absorbed by the chitosan so as to accelerate the absorption of A the synergic microcapsule and the cyhalofop-butyl ester, so that the pesticide composition is greatly reduced per mu.
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Paragraph 0022; 0035; 0043; 0046; 0054; 0057; 0065
(2021/11/26)
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- Synthesis of new Copper Catalyst with Pyrazole Based Tridentate Ligand and Study of Its Activity for Azide Alkyne Coupling
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Synthesis of new copper catalyst with pyrazole based tridentate ligand and study of its activity for azide alkyne coupling were investigated by researchers. To a solution of acetyl acetone (2.002 g, 20 mmol), 2- nitrophenylhydrazine in ethanol was added five drops of con. HCl and heated at 50° for 1 hour. After confirming the formation of 3, 5-dimethyl-1-(2-nitrophenyl)- 1H-pyrazole by TLC, ice cooled water was added in to the reaction mixture. The precipitate was filtered, washed with water and then hexane. The product formed as yellow precipitate, that precipitate had been filtered by normal filter paper. The product was recrystallized in ethanol. For synthesis, was suspended in 6 mL of deionized and stirred for 4 h until a clear solution was obtained in 50 ml round bottom flask Cu(OAc) 2. The reaction mixture was diluted with water, filtered, washed sequentially with water, methanol and n-hexane. Then dark greenish blue color crystal were formed and used for the reactions. The solid was crystallized in CH2Cl2 to get crystal whose structure was confirmed by single crystal XRD.
- Rajeswari, Panneer Selvam,Nagarajan, Rajendran,P, Sujith K,Emmanuvel, Lourdusamy
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supporting information
(2020/12/03)
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- Mechanically Strong Heterogeneous Catalysts via Immobilization of Powderous Catalysts to Porous Plastic Tablets
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Main observation and conclusion: We describe a practical and general protocol for immobilization of heterogeneous catalysts to mechanically robust porous ultra-high molecular weight polyethylene tablets using inter-facial Lifshitz-van der Waals Interactions. Diverse types of powderous catalysts, including Cu, Pd/C, Pd/Al2O3, Pt/C, and Rh/C have been immobilized successfully. The immobilized catalysts are mechanistically robust towards stirring in solutions, and they worked well in diverse synthetic reactions. The immobilized catalyst tablets are easy to handle and reused. Moreover, the metal leaching of immobilized catalysts was reduced significantly.
- Li, Tingting,Xu, Bo
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supporting information
p. 2673 - 2678
(2021/08/03)
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- Donepezil oxidation: complementary chemical and spectroscopic exploration of products, mechanism and kinetics
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Oxidation is a vital step of drug metabolism and hence a pharmaceutically relevant process. This study explores the potential of Donepezil, a widely used drug against mild to moderately severe Alzheimer's disease, to undergo oxidation using a mild, versatile oxidant Chloramine-T in acidic medium. A first-order dependency of rate on Donepezil and oxidant, fractional-order dependency on acid medium, independency of the rate on ionic concentration and an elevation of rate with increasing dielectric constant are revealed by the kinetic studies. The stoichiometry, thermodynamic properties, rate equation, mechanistic details are outlined, and identification of reaction products is supported by consistent oxidative degradation related UV, IR, 1H NMR and mass spectroscopic data. The spectroscopic results are in good agreement with theoretical predictions, providing an insight and deepen the understanding of oxidative metabolic pathway of Donepezil.
- Anantharaju, K. S.,Malini, S.,Raj, Kalyan,Suresha, N.
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- METHOD FOR PRODUCING OXIDE USING BETA-MANGANESE DIOXIDE
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With the object of efficiently producing an oxidation product, the present invention provides a method for producing an oxidation product by oxidizing a raw material compound in the presence of oxygen, wherein the raw material compound is oxidized in the presence of manganese dioxide having a crystal structure of β-type.
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Paragraph 0097; 0098
(2021/10/15)
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- Solvent-freeN-Boc deprotection byex situgeneration of hydrogen chloride gas
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An efficient, scalable and sustainable method for the quantitative deprotection of thetert-butyl carbamate (N-Boc) protecting group is described, using down to near-stoichiometric amounts of hydrogen chloride gas in solvent-free conditions. We demonstrate theex situgeneration of hydrogen chloride gas from sodium chloride and sulfuric acid in a two-chamber reactor, introducing a straightforward method for controlled and stoichiometric release of HCl gas. The solvent-free conditions allow deprotection of a wide variety ofN-Boc derivatives to obtain the hydrochloride salts in quantitative yields. The procedure obviates the need for any work-up or purification steps providing an uncomplicated green alternative to standard methods. Due to the solvent-free, anhydrous conditions, this method shows high tolerance towards acid sensitive functional groups and furnishes expanded functional group orthogonality.
- De Borggraeve, Wim M.,Gilles, Philippe,Van Mileghem, Seger,Verschueren, Rik H.
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supporting information
p. 5782 - 5787
(2021/07/12)
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- Facile synthesis of sulfonyl chlorides/bromides from sulfonyl hydrazides
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A simple and rapid method for efficient synthesis of sulfonyl chlorides/bromides from sulfonyl hydrazide with NXS (X = Cl or Br) and late-stage conversion to several other functional groups was described. A variety of nucleophiles could be engaged in this transformation, thus permitting the synthesis of complex sulfonamides and sulfonates. In most cases, these reactions are highly selective, simple, and clean, affording products at excellent yields.
- Chen, Rongxiang,Xu, Shaohong,Shen, Fumin,Xu, Canran,Wang, Kaikai,Wang, Zhanyong,Liu, Lantao
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- Visible-light enabled room-temperature dealkylative imidation of secondary and tertiary amines promoted by aerobic ruthenium catalysis
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Employing sulfonyl azide as a nitrogen donor, a visible-light-enabled aerobic dealkylative imidation of tertiary and secondary amines involving C(sp3)-C(sp3) bond cleavage with moderate to excellent yields at room temperature is described. It has been demonstrated that this imidation could take place spontaneously upon visible-light irradiation, and could be facilitated considerably by a ruthenium photocatalyst and oxygen. An alternative mechanism to the previous aerobic photoredox pathway has also been proposed.
- Yang, Dong,Shi, Jingqi,Chen, Jiaming,Jia, Xiaoqi,Shi, Cuiying,Ma, Lifang,Li, Ziyuan
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p. 18966 - 18973
(2021/06/03)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- Intermolecular C-H Amidation of Alkenes with Carbon Monoxide and Azides via Tandem Palladium Catalysis
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An atom- and step-economic intermolecular multi-component palladium-catalyzed C-H amidation of alkenes with carbon monoxide and organic azides has been developed for the synthesis of alkenyl amides. The reaction proceeds efficiently without an ortho -directing group on the alkene substrates. Nontoxic dinitrogen is generated as the sole by-product. Computational studies and control experiments have revealed that the reaction takes place via an unexpected mechanism by tandem palladium catalysis.
- Gu, Zheng-Yang,Wu, Yang,Jin, Feng,Bao, Xiaoguang,Xia, Ji-Bao
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supporting information
p. 3361 - 3371
(2021/04/09)
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- Alkene: Versus alkyne reactivity in unactivated 1,6-enynes: Regio-And chemoselective radical cyclization with chalcogens under metal-And oxidant-free conditions
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Herein, we have developed metal and oxidant-free visible light-promoted alkene vs. alkyne regio-And chemoselective radical cascade cyclization of electronically unbiased 1,6-enynes with chalcogens to synthesize substituted pyrrolidines bearing chalcogens. The reaction generated three new bonds, namely, C-SO2, C-C, and C-Se under extremely mild conditions. Furthermore, we achieved regio-And chemoselective mono-addition of aromatic thiophenols with unactivated 1,6-enynes. The key features of this protocol are broad substrate scope, environment-friendly conditions, operational simplicity, atom economy, and amenability to gram-scale synthesis. The mechanistic studies corroborate that the reaction proceeds via a radical pathway.
- Kudale, Vishal Suresh,Li, Jing,Mutra, Mohana Reddy,Tsai, Wu-Hsun,Wang, Jeh-Jeng
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supporting information
p. 2288 - 2300
(2020/04/21)
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- Palladium-Catalyzed ortho-Benzoylation of Sulfonamides through C?H Activation: Expedient Synthesis of Cyclic N-Sulfonyl Ketimines
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The ortho-carbonylation of sulfonylarenes by non-hazardous aryl aldehydes as a carbonyl precursor was reported. In this method, the sulfonamide group serves as a directing group for C?H activation in the presence of a Pd catalyst under ligand-free conditions. The scope of this strategy has been extended to the one-pot two-step synthesis of cyclic N-sulfonyl ketimines under mild reaction conditions. Our approach could be considered as an alternative by circumventing the use of highly reactive organolithium or Grignard reagents to access a wide range of biologically potent cyclic N-sulfonyl ketimines. (Figure presented.).
- Ojha, Subhadra,Panda, Niranjan
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p. 561 - 571
(2019/12/24)
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- Tetrahydropyridines via FeCl3-Catalyzed Carbonyl-Olefin Metathesis
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Herein we describe the application of Lewis-acid-catalyzed carbonyl-olefin metathesis toward the synthesis of substituted tetrahydropyridines from commercially available amino acids as chiral pool reagents. This strategy relies on FeCl3 as an inexpensive and environmentally benign catalyst and enables access to a variety of substituted tetrahydropyridines under mild reaction conditions. The reaction proceeds with complete stereoretention and is viable for a variety of natural and unnatural amino acids to provide the corresponding tetrahydropyridines in up to 99% yield.
- Gaviria, Mario A.,Groso, Emilia J.,Richardson, Alistair D.,Rykaczewski, Katie A.,Schindler, Corinna S.,Vonesh, Hannah L.,Zehnder, Troy E.
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supporting information
(2020/04/02)
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- Synthesis of N-substituted sulfonamides containing perhalopyridine moiety as bio-active candidates
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A series of new halogenated aryl sulfonamides, as bio-active candidates, was synthesized from the reaction of the corresponding aryl sulfonamides with pentafluoro- and pentachloropyridines. Surprisingly, unlike aryl sulfonamides, the reaction of sulfamides with pentafluoro- and pentachloropyridines gave unexpected bis-perfluoro(chloro)pyridin-4-ylamines.
- Hosseini, Raziyeh,Mohammadiannejad, Kazem,Ranjbar-Karimi, Reza
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- Pd-catalyzed amidation of 1,3-diketones with CO and azidesviaa nitrene intermediate
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An efficient Pd-catalyzed amidation of 1,3-diketones has been developed using carbon monoxide and organic azides. This reaction provides a step-economic approach to produce β-ketoamides from readily available compounds under mild ligand-, oxidant-, and base-free conditions. The mechanistic studies showed that the reaction occurred through anin situgenerated isocyanate intermediate.
- Gu, Zheng-Yang,Chen, Jie,Xia, Ji-Bao
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p. 11437 - 11440
(2020/10/12)
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- Harnessing Endogenous Formate for Antibacterial Prodrug Activation by in cellulo Ruthenium-Mediated Transfer Hydrogenation Reaction
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The abundance and evolving pathogenic behavior of bacterial microorganisms give rise to antibiotic tolerance and resistance which pose a danger to global public health. New therapeutic strategies are needed to keep pace with this growing threat. We propose a novel approach for targeting bacteria by harnessing formate, a cell metabolite found only in particular bacterial species, to activate an antibacterial prodrug and selectively inhibit their growth. This strategy is premised on transfer hydrogenation reaction on a biorthogonal substrate utilizing native formate as the hydride source as a means of uncaging an antibacterial prodrug. Using coordination-directed 3-component assembly to prepare a library of 768 unique Ru–Arene Schiff-base complexes, we identified several candidates that efficiently reduced sulfonyl azide functional group in the presence of formate. This strategy paves the way for a new approach of targeted antibacterial therapy by exploiting unique bacterial metabolites.
- Ang, Wee Han,Shen, Linghui,Weng, Cheng
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supporting information
p. 9314 - 9318
(2020/04/29)
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- One-pot aerobic oxidative sulfonamidation of aromatic thiols with ammonia by a dual-functional β-MnO2 nanocatalyst
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High-surface-area β-MnO2 (β-MnO2-HS) nanoparticles could act as effective heterogeneous catalysts for the one-pot oxidative sulfonamidation of various aromatic and heteroaromatic thiols to the corresponding sulfonamides using molecular oxygen (O2) and ammonia (NH3) as respective oxygen and nitrogen sources, without the need for any additives.
- Hayashi, Eri,Yamaguchi, Yui,Kita, Yusuke,Kamata, Keigo,Hara, Michikazu
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supporting information
p. 2095 - 2098
(2020/02/26)
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- Mild, Rapid, and Chemoselective Procedure for the Introduction of the 9-Phenyl-9-fluorenyl Protecting Group into Amines, Acids, Alcohols, Sulfonamides, Amides, and Thiols
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The 9-phenyl-9-fluorenyl (PhF) group has been used as an Nα protecting group of amino acids and their derivatives mainly as a result of its ability to prevent racemization. However, installing this group using the standard protocol, which employs 9-bromo-9-phenylfluorene/K3PO4/Pb(NO3)2, often takes days and yields can be variable. Here, we demonstrate that the PhF group can be introduced into the amino group of Weinreb's amides and methyl esters of amino acids, as well as into alcohols and carboxylic acids, rapidly and in excellent yields, using 9-chloro-9-phenylfluorene (PhFCl)/N-methylmorpholine (NMM)/AgNO3. Nα-PhF-protected amino acids can be prepared from unprotected α-amino acids, rapidly and often in near quantitative yields, by treatment with N,O-bis(trimethylsilyl)acetamide (BSA) and then PhFCl/NMM/AgNO3. Primary alcohols can be protected with the PhF group in the presence of secondary alcohols in moderate yield. Using PhFCl/AgNO3, a primary alcohol can be protected in good yield in the presence of a primary ammonium salt or a carboxylic acid. Primary sulfonamides and amides can be protected in moderate to good yields using phenylfluorenyl alcohol (PhFOH)/BF3·OEt2/K3PO4, while thiols can be protected in good to excellent yield using PhFOH/BF3·OEt2 even in the presence of a carboxylic acid or primary ammonium group.
- Soley, Jacob,Taylor, Scott D.
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- Hydroxylamines As Bifunctional Single-Nitrogen Sources for the Rapid Assembly of Diverse Tricyclic Indole Scaffolds
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Conventional approaches on using hydroxylamine derivatives as single nitrogen sources, for the construction of n-membered (n > 3) N-heterocycles, rely upon two chemical operations by involving sequential nucleophilic and electrophilic C-N bond formations. Here, we report a highly efficient cascade of alkyne insertion/C-H activation/amination for the rapid preparation of a myriad of tricyclic indoles, in a single-step transformation, by using bifunctional secondary hydroxylamines. It is noteworthy that judicious selection of applicable amino agents, for enabling the prior oxidative addition of aryl iodide to initial Pd(0) species and subsequent two C-N bonds formation, was the key to the success of this reaction. Control experiments indicated that a five-membered palladacyclic intermediate played a crucial role in promoting the final aminative ring closure.
- Fan, Liangxin,Hao, Jiamao,Liu, Jingjing,Luan, Xinjun,Ma, Xiaojun,Yu, Jingxun
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supporting information
p. 6698 - 6707
(2020/04/30)
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- Photocatalytic α-Tertiary Amine Synthesis via C?H Alkylation of Unmasked Primary Amines
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A practical, catalytic entry to α,α,α-trisubstituted (α-tertiary) primary amines by C?H functionalisation has long been recognised as a critical gap in the synthetic toolbox. We report a simple and scalable solution to this problem that does not require any in situ protection of the amino group and proceeds with 100 percent atom-economy. Our strategy, which uses an organic photocatalyst in combination with azide ion as a hydrogen atom transfer (HAT) catalyst, provides a direct synthesis of α-tertiary amines, or their corresponding γ-lactams. We anticipate that this methodology will inspire new retrosynthetic disconnections for substituted amine derivatives in organic synthesis, and particularly for challenging α-tertiary primary amines.
- Alder, Catherine M.,Ballantyne, George,Cresswell, Alexander J.,Cunningham, William B.,Edwards, Lee J.,Grayson, Matthew N.,Kinsella, Anna G.,McKay, Blandine S. J.,Mules, Tom,Ryder, Alison S. H.,Turner-Dore, Jacob
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supporting information
p. 14986 - 14991
(2020/06/20)
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- Primary Sulfonamide Synthesis Using the Sulfinylamine Reagent N-Sulfinyl- O-(tert-butyl)hydroxylamine, t-BuONSO
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Sulfonamides have played a defining role in the history of drug development and continue to be prevalent today. In particular, primary sulfonamides are common in marketed drugs. Here we describe the direct synthesis of these valuable compounds from organometallic reagents and a novel sulfinylamine reagent, t-BuONSO. A variety of (hetero)aryl and alkyl Grignard and organolithium reagents perform well in the reaction, providing primary sulfonamides in good to excellent yields in a convenient one-step process.
- Davies, Thomas Q.,Hall, Adrian,Skolc, David,Tilby, Michael J.,Willis, Michael C.
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supporting information
p. 9495 - 9499
(2020/12/21)
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- Ethynylbenziodazolones (EBZ) as Electrophilic Alkynylation Reagents for the Highly Enantioselective Copper-Catalyzed Oxyalkynylation of Diazo Compounds
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Ethynylbenziodoxol(on)e (EBX) cyclic hypervalent iodine reagents are now established reagents for the alkynylation of radicals and nucleophiles, yet they present limited possibilities for further structure and reactivity modification. Herein, the first synthesis is reported for the corresponding ethynylbenziodazolone (EBZ) reagents, in which the oxygen atom in the iodoheterocycle is replaced by a nitrogen atom. The substituent on the nitrogen enables further fine-tuning of the reagent structure and reactivity. EBZ reagents are obtained easily from the corresponding benzamides by using a one-step procedure, and display reactivity comparable to that of EBX reagents. In particular, they are applied in an asymmetric copper-catalyzed oxyalkynylation of diazo compounds, which proceeds in high yield and enantioselectivity for a broad range of substituents on the diazo compounds and the alkyne.
- Hari, Durga Prasad,Schouwey, Lionel,Barber, Verity,Scopelliti, Rosario,Fadaei-Tirani, Farzaneh,Waser, Jerome
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supporting information
(2019/05/28)
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- High yielding protocol for direct conversion of thiols to sulfonyl chlorides and sulfonamides
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In this paper, a new method for oxidative chlorination of thiols to sulfonyl chlorides and sulfonamides using H2O2 in the presence of TMSCl is reported. The excellent yields, short reaction times, excellent efficiencies, low costs, and easy separation of products are the most important advantages of this method.
- Sohrabnezhad, Samira,Bahrami, Kiumars,Hakimpoor, Farahman
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p. 256 - 264
(2019/02/06)
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- Rational Design, synthesis and biological evaluation of novel triazole derivatives as potent and selective PRMT5 inhibitors with antitumor activity
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Protein arginine methyltransferase 5 (PRMT5) is responsible for the mono-methylation and symmetric dimethylation of arginine, and its expression level and methyl transferring activity have been demonstrated to have a close relationship with tumorigenesis, development and poor clinical outcomes of human cancers. Two PRMT5 small molecule inhibitors (GSK3326595 and JNJ-64619178) have been put forward into clinical trials. Here, we describe the design, synthesis and biological evaluation of a series of novel, potent and selective PRMT5 inhibitors with antiproliferative activity against Z-138 mantle cell lymphoma cell line. Among them, compound C_4 exhibited the highest potency with enzymatic and cellular level IC50 values of 0.72 and 2.6 μM, respectively, and displayed more than 270-fold selectivity toward PRMT5 over several other isoenzymes (PRMT1, PRMT4 and PRMT6). Besides, C_4 demonstrated obvious cell apoptotic effect while reduced the cellular symmetric arginine dimethylation levels of SmD3 protein. The potency, small size, and synthetic accessibility of this compound class provide promising hit scaffold for medicinal chemists to further explore this series of PRMT5 inhibitors.
- Zhu, Kongkai,Shao, Jingwei,Tao, Hongrui,Yan, Xue,Luo, Cheng,Zhang, Hua,Duan, Wenhu
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p. 775 - 785
(2019/07/22)
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- Easy-handling and low-leaching heterogeneous palladium and platinum catalysts via coating with a silicone elastomer
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We have developed a practical protocol for coating of commercial Pd/Al2O3 and Pt/Al2O3 catalysts in micro-powders with a silicone elastomer. Compared to original catalysts, the treated catalysts are easier to weight and transfer, and they are easier to recover by simple filtration. More importantly, the metal leaching of treated catalysts was significantly reduced. The treated catalysts worked very well in diverse hydrogenation reactions.
- Zhou, Mi,Li, Tingting,Xu, Bo
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supporting information
p. 948 - 952
(2019/03/08)
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- Na2S-promoted reduction of azides in water: Synthesis of pyrazolopyridines in one pot and evaluation of antimicrobial activity
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Reduction of various azides using Na2S has been accomplished in water, and, in situ, the resulting amines on reaction with various ketones lead to pyrazolo[3,4-b]pyridines in one pot. Thus, a number of new trifluoromethyl-substituted pyrazolo[3,4-b]pyridine compounds have been prepared and screened for antimicrobial activity against different Gram-positive and Gram-negative strains. A good number of compounds, 4a, 4b, 4d, 4f, 4i, 4k, 4l, 4m, 4r and 4s, were found to possess promising activity. Notably, Na2S on hydrolysis in water generates H2S and NaOH, which facilitate the reduction of azides followed by intramolecular cyclization leading to the title compounds. To the best of our knowledge, this is the first report of the synthesis of the title compounds in aqueous medium in a one-pot reaction.
- Kale, Ashok,Medishetti, Nagaraju,Kanugala, Sirisha,Ganesh Kumar,Atmakur, Krishnaiah
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p. 3186 - 3194
(2019/03/26)
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- Methyl-triflate-mediated dearylmethylation of: N -(arylmethyl)carboxamides via the retro-Mannich reaction induced by electrophilic dearomatization/rearomatization in an aqueous medium at room temperature
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We have developed a protocol for the dearylmethylation of N-(arylmethyl)carboxamides under metal-free conditions in an aqueous medium at room temperature. This protocol involves methyl triflate-mediated successive C-C and C-N bond cleavages (retro-Mannich reaction) induced by electrophilic dearomatization/rearomatization. The dearomatization/rearomatization strategy can be expected to inspire the development of novel transformations based on the C-C bond cleavage in an environmentally benign manner.
- Peng, Hui,Ma, Jinhui,Luo, Wenkun,Zhang, Guangwen,Yin, Biaolin
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supporting information
p. 2252 - 2256
(2019/05/17)
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- Sulfonylimino group transfer reaction using imino-λ3-iodanes with I2 as catalyst under metal-free conditions
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A new practical procedure of imination for sulfide has been developed. The treatment of (N-tosylimino)-phenyl-λ3-iodane, PhINTs, with various sulfides in the presence of a catalytic amount of I2 under metal-free conditions affords the corresponding N-tosylsulfilimine compounds with moderate to good yields. This facile transfer procedure of the sulfonylimino group can also be applied to triphenylphosphine to produce the respective iminotriphenylphosphoranes in high yields. According to the reaction mechanism studies, the process of imination from (N-tosylimino)-phenyl-λ3-iodane to sulfide under the conditions may involve radical steps within the reaction mechanism.
- Yoshimura, Akira,Makitalo, Cody L.,Jarvi, Melissa E.,Shea, Michael T.,Postnikov, Pavel S.,Rohde, Gregory T.,Zhdankin, Viktor V.,Saito, Akio,Yusubov, Mekhman S.
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- Sulfonamide compound and synthesis method and application thereof
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The invention discloses a synthesis method of a sulfonamide compound represented in a formula (2). According to the method, diazonium salt is used as a reaction raw material, and under the action of an inorganic nitrogen reagent, an inorganic sulfur dioxide reagent, an additive and a phosphine reagent, the diazonium salt is reacted in a solvent at 60-100 DEG C to obtain various sulfonamide compounds. According to the method inorganic salt is used as a nitrogen atom source and a sulfur dioxide source under a metal-free catalytic condition to construct the sulfonamide compound through one step,thereby avoiding the conventional multi-step synthesis of sulfonamide by condensing unstable acid chloride and amine; and the developed sulfonamide synthesis method can be further applied to the synthesis of the arthritis drug celecoxib and the psychotropic drug sulpiride.
- -
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Paragraph 0042-0045
(2019/04/02)
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- Trispyrazolylborate Ligands Supported on Vinyl Addition Polynorbornenes and Their Copper Derivatives as Recyclable Catalysts
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Polynorbornenes prepared by vinyl addition polymerization and bearing pendant alkenyl groups serve as skeletons to support trispyrazolylborate ligands (Tpx) built at those alkenyl sites. Reaction with CuI in acetonitrile led to VA-PNB–TpxCu(NCMe) (VA-PBN=vinyl addition polynorbornene) with a 0.8–1.4 mmol incorporation of Cu per gram of polymer. The presence of tetracoordinated copper(I) ions was been assessed by FTIR studies on the corresponding VA-PNB-TpxCu(CO) adducts, in agreement with those on discrete TpxCu(CO). The new materials were employed as heterogeneous catalysts in several carbene- and nitrene-transfer reactions, showing a behavior similar to that of the homogeneous counterparts but also being recycled several times maintaining a high degree of activity and selectivity. This is the first example of supported Tpx ligands onto polymeric supports with catalytic applications.
- Molina de la Torre, Jesús A.,Pérez-Ortega, Ignacio,Beltrán, álvaro,Rodríguez, Manuel R.,Díaz-Requejo, M. Mar,Pérez, Pedro J.,Albéniz, Ana C.
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p. 556 - 563
(2018/12/11)
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- Intermolecular C?H Amidation of (Hetero)arenes to Produce Amides through Rhodium-Catalyzed Carbonylation of Nitrene Intermediates
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Amide bond formation is one of the most important reactions in organic chemistry because of the widespread presence of amides in pharmaceuticals and biologically active compounds. Existing methods for amides synthesis are reaching their inherent limits. Described herein is a novel rhodium-catalyzed three-component reaction to synthesize amides from organic azides, carbon monoxide, and (hetero)arenes via nitrene-intermediates and direct C?H functionalization. Notably, the reaction proceeds in an intermolecular fashion with N2 as the only by-product, and either directing groups nor additives are required. The computational and mechanistic studies show that the amides are formed via a key Rh-nitrene intermediate.
- Yuan, Si-Wen,Han, Hui,Li, Yan-Lin,Wu, Xueli,Bao, Xiaoguang,Gu, Zheng-Yang,Xia, Ji-Bao
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supporting information
p. 8887 - 8892
(2019/05/29)
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- Engineering Chemoselectivity in Hemoprotein-Catalyzed Indole Amidation
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Here we report a cytochrome P450 variant that catalyzes C2-amidation of 1-methylindoles with tosyl azide via nitrene transfer. Before evolutionary optimization, the enzyme exhibited two undesired side reactivities resulting in reduction of the putative iron-nitrenoid intermediate or cycloaddition between the two substrates to form triazole products. We speculated that triazole formation was a promiscuous cycloaddition activity of the P450 heme domain, while sulfonamide formation likely arose from surplus electron transfer from the reductase domain. Directed evolution involving mutagenesis of both the heme and reductase domains delivered an enzyme providing the desired indole amidation products with up to 8400 turnovers, 90% yield, and a shift in chemoselectivity from 2:19:1 to 110:12:1 in favor of nitrene transfer over reduction or triazole formation. This work expands the substrate scope of hemoprotein nitrene transferases to heterocycles and highlights the adaptability of the P450 scaffold to solve challenging chemoselectivity problems in non-natural enzymatic catalysis.
- Brandenberg, Oliver F.,Miller, David C.,Markel, Ulrich,Ouald Chaib, Anissa,Arnold, Frances H.
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p. 8271 - 8275
(2019/08/22)
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- Catalyst-controlled regiodivergent ring-opening C(sp3)-Si bond-forming reactions of 2-arylaziridines with silylborane enabled by synergistic palladium/copper dual catalysis
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A catalyst-controlled regiodivergent and stereospecific ring-opening C(sp3)-Si cross-coupling of 2-arylaziridines with silylborane enabled by synergistic Pd/Cu dual catalysis has been developed. Just by selecting a suitable combination of catalysts, the regioselectivity of the coupling is completely switched to efficiently provide two regioisomers of β-silylamines (i.e., β-silyl-α-phenethylamines and β-silyl-β-phenethylamines) in good to high yields. Furthermore, a slight modification of the reaction conditions caused a drastic change in reaction pathways, leading to a tandem reaction to produce another regioisomer of silylamine (i.e., α-silyl-β-phenethylamines) in an efficient and selective manner.
- Takeda, Youhei,Shibuta, Kaoru,Aoki, Shohei,Tohnai, Norimitsu,Minakata, Satoshi
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p. 8642 - 8647
(2019/10/02)
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- Nitrene transfer catalyzed by a non-heme iron enzyme and enhanced by non-native small-molecule ligands
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Transition-metal catalysis is a powerful tool for the construction of chemical bonds. Here we show that Pseudomonas savastanoi ethylene-forming enzyme, a non-heme iron enzyme, can catalyze olefin aziridination and nitrene C-H insertion, and that these activities can be improved by directed evolution. The non-heme iron center allows for facile modification of the primary coordination sphere by addition of metal-coordinating molecules, enabling control over enzyme activity and selectivity using small molecules.
- Goldberg, Nathaniel W.,Knight, Anders M.,Zhang, Ruijie K.,Arnold, Frances H.
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p. 19585 - 19588
(2019/12/24)
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- β-(Cycloalkylamino)ethanesulfonyl azides as novel water-soluble reagents for the synthesis of diazo compounds and heterocycles
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[Figure not available: see fulltext.] Novel water-soluble sulfonyl azides were synthesized, which are basic by nature. The obtained compounds were used as donors of the diazo group in the diazo transfer reaction. Due to their good solubility in water and high polarity, the byproducts formed in this case were easily separated from the desired products by washing with water or column chromatography. It was also shown that new sulfonyl azides as a result of reactions can be incorporated in heterocyclic products, imparting them water solubility.
- Shafran, Yuri M.,Silaichev, Pavel S.,Bakulev, Vasiliy A.
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p. 1251 - 1261
(2020/01/11)
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- Design, synthesis and biological evaluation of novel phenylsulfonylurea derivatives as PI3K/mTOR dual inhibitors
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Five series of novel phenylsulfonylurea derivatives, 19a–d, 20a–d, 21a–d, 22a–d and 23a–d, bearing 4-phenylaminoquinoline scaffold were designed, synthesized and their IC50 values against four cancer cell lines (HepG-2, A549, PC-3 and MCF-7) were evaluated. Most compounds showed moderate cytotoxicity activity against the cancer cell lines. Structure–activity relationships (SARs) and pharmacological results indicated that introduction of 4-aminoquinoline scaffold and phenylsulfonylurea scaffold were beneficial for anti-tumor activity. Moreover, para-methoxyl substitution of 4-anilino moiety and para-halogen substitution of phenylsulfonylurea have different impacts on different series of compounds. Furthermore, the micromolecule group substitution in the 6-position of the quinoline ring have a slight impact on the cellular activity of the target compounds.
- Zhao, Bingbing,Lei, Fei,Wang, Caolin,Zhang, Binliang,Yang, Zunhua,Li, Wei,Zhu, Wufu,Xu, Shan
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- Three-Component Ring-Opening Reactions of Cyclic Ethers, α-Diazo Esters, and Weak Nucleophiles under Metal-Free Conditions
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A protocol for three-component reactions of cyclic ethers, α-diazo esters, and weak nitrogen, oxygen, carbon, and sulfur nucleophiles (pKa = 2.2-14.8) to afford a variety of structurally complex α-oxyalkylated esters is reported. These reactions involve intermolecular activation of the cyclic ether (present in excess) by the α-diazo ester to form an oxonium ylide under metal-free conditions, followed by ring opening by the nucleophile.
- Lu, Lin,Chen, Chuwei,Jiang, Huanfeng,Yin, Biaolin
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p. 14385 - 14395
(2018/11/27)
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- An Isolable Terminal Imido Complex of Palladium and Catalytic Implications
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Herein, we report the isolation and a reactivity study of the first example of an elusive palladium(II) terminal imido complex. This scaffold is an alleged key intermediate for various catalytic processes, including the amination of C?H bonds. We demonstrate facile nitrene transfer with H?H, C?H, N?H, and O?H bonds and elucidate its role in catalysis. The high reactivity is due to the population of the antibonding highest occupied molecular orbital (HOMO), which results in unique charge separation within the closed-shell imido functionality. Hence, N atom transfer is not necessarily associated with the high valency of the metal (PdIII, PdIV) or the open-shell character of a nitrene as commonly inferred.
- Grünwald, Annette,Orth, Nicole,Scheurer, Andreas,Heinemann, Frank W.,P?thig, Alexander,Munz, Dominik
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p. 16228 - 16232
(2018/11/23)
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- Visible-light-driven Efficient Photocatalytic Reduction of Organic Azides to Amines over CdS Sheet–rGO Nanocomposite
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CdS sheet–rGO nanocomposite as a heterogeneous photocatalyst enables visible-light-induced photocatalytic reduction of aromatic, heteroaromatic, aliphatic and sulfonyl azides to the corresponding amines using hydrazine hydrate as a reductant. The reaction shows excellent conversion and chemoselectivity towards the formation of the amine without self-photoactivated azo compounds. In the adopted strategy, CdS not only accelerates the formation of nitrene through photoactivation of azide but also enhances the decomposition of azide to a certain extent, which entirely suppressed formation of the azo compound. The developed CdS sheet-rGO nanocomposite catalyst is very active, providing excellent results under irradiation with a 40 W simple household CFL lamp.
- Singha, Krishnadipti,Mondal, Aniruddha,Ghosh, Subhash Chandra,Panda, Asit Baran
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p. 255 - 260
(2018/01/15)
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- Copper-mediated reduction of azides under seemingly oxidising conditions: Catalytic and computational studies
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The reduction of aryl azides in the absence of an obvious reducing agent is reported. Careful catalyst design led to the production of anilines in the presence of water and air. The reaction medium (toluene/water) is crucial for the success of the reaction, as DFT calculations support the formation of benzyl alcohol as the oxidation product. A singular catalytic cycle is presented for this transformation based on four key steps: nitrene formation through nitrogen extrusion, formal oxidative addition of water, C(sp3)-H activation of toluene and reductive elimination.
- Zelenay, Benjamin,Besora, Maria,Monasterio, Zaira,Ventura-Espinosa, David,White, Andrew J. P.,Maseras, Feliu,Díez-González, Silvia
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p. 5763 - 5773
(2018/11/24)
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