- Metal-Free C?H Borylation of N-Heteroarenes by Boron Trifluoride
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Organoboron compounds are essential reagents in modern C?C coupling reactions. Their synthesis via catalytic C?H borylation by main group elements is emerging as a powerful tool alternative to transition metal based catalysis. Herein, a straightforward metal-free synthesis of aryldifluoroboranes from BF3 and heteroarenes is reported. The reaction is assisted by sterically hindered amines and catalytic amounts of thioureas. According to computational studies the reaction proceeds via frustrated Lewis pair (FLP) mechanism. The obtained aryldifluoroboranes are further stabilized against destructive protodeborylation by converting them to the corresponding air stable tetramethylammonium organotrifluoroborates.
- Iashin, Vladimir,Berta, Dénes,Chernichenko, Konstantin,Nieger, Martin,Moslova, Karina,Pápai, Imre,Repo, Timo
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supporting information
p. 13873 - 13879
(2020/10/02)
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- THIOL COMPOUND PRODUCTION METHOD AND NOVEL THIATING AGENT
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PROBLEM TO BE SOLVED: To provide: a thiol compound production method which allows selective production of a thiol compound of interest, inhibits production of by-products ending up wastes, is excellent in production efficiency, and can reduce production costs; and a novel thiating agent used for the method. SOLUTION: The thiol compound production method comprises: a step 1 of preparing a thiuronium salt by reacting at least one compound represented by the general formula (1) defined by R-(X)m with a thiating agent comprising at least one compound selected from compounds represented by the general formula (2) in the figure; and a step 2 of hydrolyzing the thiuronium salt to prepare a compound represented by the general formula (3) defined by R-(SH)m. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPOandINPIT
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Paragraph 0066
(2019/12/25)
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- Precursor reaction kinetics control compositional grading and size of CdSe1-: XSx nanocrystal heterostructures
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We report a method to control the composition and microstructure of CdSe1-xSx nanocrystals by the simultaneous injection of sulfide and selenide precursors into a solution of cadmium oleate and oleic acid at 240 °C. Pairs of substituted thio- and selenoureas were selected from a library of compounds with conversion reaction reactivity exponents (kE) spanning 1.3 × 10-5 s-1 to 2.0 × 10-1 s-1. Depending on the relative reactivity (kSe/kS), core/shell and alloyed architectures were obtained. Growth of a thick outer CdS shell using a syringe pump method provides gram quantities of brightly photoluminescent quantum dots (PLQY = 67 to 90%) in a single reaction vessel. Kinetics simulations predict that relative precursor reactivity ratios of less than 10 result in alloyed compositions, while larger reactivity differences lead to abrupt interfaces. CdSe1-xSx alloys (kSe/kS = 2.4) display two longitudinal optical phonon modes with composition dependent frequencies characteristic of the alloy microstructure. When one precursor is more reactive than the other, its conversion reactivity and mole fraction control the number of nuclei, the final nanocrystal size at full conversion, and the elemental composition. The utility of controlled reactivity for adjusting alloy microstructure is discussed.
- Hamachi, Leslie S.,Yang, Haoran,Jen-La Plante, Ilan,Saenz, Natalie,Qian, Kevin,Campos, Michael P.,Cleveland, Gregory T.,Rreza, Iva,Oza, Aisha,Walravens, Willem,Chan, Emory M.,Hens, Zeger,Crowther, Andrew C.,Owen, Jonathan S.
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p. 6539 - 6552
(2019/07/10)
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- A catalyst-free and additive-free method for the synthesis of benzothiazolethiones from: O -iodoanilines, DMSO and potassium sulfide
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Under catalyst-free and additive-free conditions, a novel, convenient, eco-friendly method for the synthesis of benzothiazolethiones has been developed. The three-component reaction of o-iodoanilines and K2S with DMSO proceeded smoothly and the corresponding benzothiazolethiones were obtained with good isolated yields. Meanwhile, this method could be used for the synthesis of thioureas from primary diamines. Furthermore, mechanism research showed that DMSO not only functioned as a carbon source, but also as a mild oxidant in this reaction.
- Zhu, Xiaoming,Li, Wenguang,Luo, Xiai,Deng, Guobo,Liang, Yun,Liu, Jianbing
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supporting information
p. 1970 - 1974
(2018/05/23)
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- Synthesis, spectroscopic characterization and in vitro anticancer activity of new platinum(II) complexes with some thione ligands?in the presence of triethylphosphine
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Seven new platinum(II) complexes (1–7) of triethylphosphine (Et3P) and thiones (L) with general formula, cis-[Pt(Et3P)2(L)2]Cl2 were prepared and characterized by elemental analysis, FTIR and NMR (1H, 13C & 31P) measurements. The analytical and spectroscopic data suggested the formation of the desired complexes. The complexes were tested for in vitro cytotoxicity against four cell lines: Hela (human cervical adenocarcinoma), MCF-7 (human breast carcinoma), A549 (human lung carcinoma), and HTC15 (human colon carcinoma). The anticancer activity values of compounds 1–6 are much better than cisplatin and carboplatin as indicated by their IC50 values.
- Jomaa, Mohammed Yagoub,Altaf, Muhammed,Ahmad, Saeed,Bhatia, Gaurav,Singh, Jatinder,Altuwaijri, Saleh,Isab, Anvarhusein A.
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p. 787 - 795
(2017/10/13)
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- Bis-(triethylphosphine)platinum(II) complexes with thiones as anti cancer agents
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Platinum(II) complexes having mixed ligands as anticancer agents. The central platinum atom is coordinated by two phosphine ligands and two heterocyclic thione ligands. Each heterocyclic thione ligand has a five-, six- or seven-membered heterocyclic ring with two nitrogen atoms at positions 1 and 3 of the ring and a thiocarbonyl group at position 2. Pharmaceutical compositions incorporated the platinum(II) complexes, methods of synthesizing the complexes and methods of treating cancers with the complexes or pharmaceutical compositions thereof are also described.
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Page/Page column 20
(2017/02/28)
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- Development of Thiourea-Based Ligands for the Palladium-Catalyzed Bis(methoxycarbonylation) of Terminal Olefins
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Thiourea-based ligands were evaluated for the palladium-catalyzed bis(methoxycarbonylation) of terminal olefins. The usefulness of these ligands for this reaction is demonstrated by their stability to oxidizing agents, and their superiority in preventing
- Dai, Mingji,Wang, Cuihua,Dong, Guangbin,Xiang, Jing,Luo, Tuoping,Liang, Bo,Chen, Jiahua,Yang, Zhen
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p. 4346 - 4348
(2007/10/03)
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- C-H activation with elemental sulfur: Synthesis of cyclic thioureas from formaldehyde aminals and S8
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The C-H activation of cyclic formaldehyde aminals LCH2 (L = RNCH2CH2CH2-NR and RNCH2CH2-NR, R = Me, Et, iPr, tBu, or Ph) with S8 proceeds at unusually low temperatures (T 2S. The reaction constitutes a new, solvent-free method for the synthesis of thioureas that eliminates the toxic and highly flammable CS2. For R = tBu, the ionic carbenium thiocyanates [LCH]+ SCN- dominate the product spectrum and the respective thioureas are obtained in low yield. The reactivity of the analogous sulfur and oxygen ring systems towards S8 was investigated. 1,3-Dithiolane is cleanly converted into 1,3-dithiolane-2-thione (S8, 14 d, 190°C) and resembles the cyclic formaldehyde aminals in this respect. 1,3-Dioxolane (L = OCH2CH2O) is completely inert towards sulfur even under forceful reaction conditions (190°C, 14 d). The formation of thioureas from aminals was investigated at the CBS-4 and B3LYP/6-31G(d) levels of theory.
- Denk, Michael K.,Gupta, Shilpi,Brownie, John,Tajammul, Sabiha,Lough, Alan J.
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p. 4477 - 4486
(2007/10/03)
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- Efficient synthesis of 2-methylaminothiazolines via Mitsunobu reaction of N-(2-hydroxyethyl)-N'-methyl-thioureas
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2-Methylaminothiazolines 3 were synthesized selectively from N-(2- hydroxyethyl)-thioureas 2 by the intramolecular Mitsunobu reaction.
- Kim, Taek Hyeon,Cha, Mi-Hyun
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p. 3125 - 3128
(2007/10/03)
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- Ambident reactivities of carbenium salts possessing a thiocarbonyl group at the β-position
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A stable, crystalline carbenium iodide, which possesses a thiocarbonyl group at the β-position, shows ambident reactivities, thereby reacting with a hard nucleophile OH- at the carbenium carbon atom and with a soft nucleophile RLi at the thioca
- Nakayama, Juzo,Kitahara, Taku,Sugihara, Yoshiaki,Ishii, Akihiko
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p. 187 - 188
(2007/10/03)
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- Synthesis and antimicrobial activity of electron rich olefin derived cyclic ureas
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Seventeen cyclic ureas containing imidazolidine and benzimidazoline nuclei were synthesised by the reaction of electron-rich olefins with appropriate group 16 elements (O, S, Se, Te). The compounds synthesised were identified by 1H, 13C-NMR, FT-IR and mass spectroscopic techniques and micro analysis. All compounds studied in this work were screened for their in vitro antimicrobial activity against standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853). Eight of the compounds were found effective to inhibit the growth of Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) at MIC values between 25-400 μg/ml. None of the compounds exhibit antimicrobial activity against gram-negative bacteria (Escherichia coli and Pseudmonas aeruginosa) at the concentrations studied (6.25-800 μg/ml).
- Cetinkaya, Bekir,Cetinkaya, Engin,Kuecuekbay, Hasan,Durmaz, Riza
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p. 1154 - 1158
(2007/10/03)
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- Aminosilylation of heterocumulenes and the intramolecular decomposition of their silyl-functionalized adducts
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Heteroorganic amidosilanes are readily obtained by interaction of CO2, CS2 and other heterocumulenes with pentacoordinated diaminosilanes.A comparison is made with the corresponding reactions of tetracoordinated species.Decompositon of these bifunctional organosilanes gives 2-substituted ureido derivatives and base-stabilized low coordinated silicon species, seemingly by a unimolecular thermal β-elimination.
- Corriu, R. J. P.,Lanneau, Gerard F.,Mehta, V. D.
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- THE NUCLEOPHILICITY OF SUBSTITUTED THIOUREAS TOWARDS PLATINUM(II) SUBSTRATES
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The kinetics of the displacement of chloride from three platinum(II) substrates, trans- (py = pyridine), K and ClO4 (dien = 1,5-diamino-3-azapentane) by a series of substituted thioureas have been studied in methanol
- Cattalini, Lucio,Bonivento, Massimiliano,Michelon, Gianni,Tobe, Martin L.,Treadgold, Andrew T.
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p. 725 - 728
(2007/10/02)
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- THIONO COMPOUNDS. 5. PREPARATION AND OXIDATION OF SOME THIONO DERIVATIVES OF IMIDAZOLES
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1,3-Dimethyl-3H-imidazole-2-thione (3), prepared by a much improved procedure from 1,3-dimethylimidazolium iodide (6) with sulfur and organic base, was oxidized with H2O2 in MeOH; three molar proportions of H2O2 were consumed, 1,3-dimethylimidazolium picrate (14; synthesized independently) was isolated in 61percent yield, and 80percent of the expected sulfate ion was found.Oxidation of the analogous imidazolidine (4), prepared from 1,3-dimethyl-2-imidazolidone (16) with Lawesson's reagent (17), gave a counterpart picrate (73percent from 4) in a similar but slower reaction. 1,3-Diphenyl-2-imidazolidinethione (5) had to be oxidized in DMF-AcOH, with H2SO4 catalysis, and only 1,3-diphenyl-2-imidazolidone (19, 63percent) could be isolated.Understanding is added to the behavior in oxidations of thiono derivatives of imidazoles by these extensions of several earlier studies to different types within the class, i.e., of an N-unsubstituted one (1) to the N,N-dimethyl counterpart (4), of an N-methyl unsaturated one (2) to the N,N-dimethyl counterpart (3), and of an N,N-diphenyl unsaturated one (23) to the saturated counterpart (5).Similarities and differences are discussed relative to members of the class studied previously, along with information that improves understanding of the different courses of reactions various members of the class may follow when they are oxidized.
- Karkhanis, Dattatraya W.,Field, Lamar
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- MACROHETEROCYCLES. XXII. N,N'-DIALKYLDIAZA(OXA)CYCLOALKANETHIONES, SYNTHESIS AND PROPERTIES
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During the alkylation of diaza(oxa)cycloalkanethiones with halogenoalkanes in a two-phase system in the presence of potassium carbonate the corresponding N,N'-dialkylthiuronium salts are formed.Heating of the latter under vacuum leads to the elimination of the halogenoalkanes and the formation of N,N'-dialkyldiaza(oxa)cycloalkanethiones, including new crown compounds.The cationic selectivity of the latter with respect to the ions of alkali and alkaline-earth metals was determined.
- Bogat-skii, A. V.,Luk'yanenko, N. G.,Kirichenko, T. I.,Limich, V. V.,Nazarova, N. Yu.,Karpenko, L. P.
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p. 1379 - 1385
(2007/10/02)
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- Crystal structure of N,N'-dimethyl-2-imidazolidinethione, a by-product from the reaction of Na2(CH2N(CH3)CS2)2 and HgCl2
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The reaction between mercury (II) chloride and N,N'-dimethylethylenebisdithiocarbamate gave a white precipitate.In an attempted recrystallization from an aqueous-ethanol solution, a cyclic thiourea-type compound, N,N-dimethyl-2-imidazolidinethione, was obtained.The crystals of this compound are monoclinic, a = 10.388(2), b = 6.139(1), c = 12.291(4) Angstroem, β = 118.64(2), and space group P21/c.The non-hydrogen atoms of the molecule are planar and the C=S bond length is 1.673(4) Angstroem.The strusture was refined by full-matrix least-squares from 642 independent reflections measured on an automatic diffractometer to R and RW of 0.053 and 0.068 respectively.
- Chieh, Chung,Cheung, Sing Kwen
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p. 211 - 213
(2007/10/02)
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- Comparative radioprotective activity of various pentagonal compounds with two heteroatomes
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Various heterocyclic compounds with two heteroatomes were synthesized and their potential radioprotective activity was tested. This study shows the interest of phenylthiazolidines derivatives in chemical radioprotection.
- Robbe,Fernandez,Dubief,et al.
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p. 235 - 243
(2007/10/02)
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- Cyclic Urea and Thiourea Derivatives as Inducers of Murine Erythroleukemia Differentiation
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A series of derivatives of tetramethylurea, a known inducer of the differentiation of Friend erythroleukemia cells, has been synthesized and tested for its capacity to induce erythroid maturation, as measured by the synthesis of hemoglobin.Cyclic urea and thiourea derivatives consisting of five-, six-, and seven-membered ring systems containing N-alkyl substituents were prepared.Most of these agents were relatively effective inducers of differentiation, with N-alkyl substitution appearing to be essential for maximum response.The most potent agents developed wereN,N'-dimethyl cyclic ureas.Exposure to concentrations of 2 to 4 mM of these derivatives resulted in more than 90percent of the cell population achieving a differentiated state.Under these conditions, the parent compound, tetramethylurea, was slightly less efficacious, causing differentiation of only 68percent of the population at its maximum effective level of 4 mM.
- Li, Chau-der,Mella, Sharon L.,Sartorelli, Alan C.
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p. 1089 - 1092
(2007/10/02)
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