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Journal articles on the topic 'Thiourea Catalysts'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 September 2023

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1

Pitchumani, Venkatachalam, and David W. Lupton. "Studies on Thiourea Catalysed Bromocycloetherification and Bromolactonisations." Australian Journal of Chemistry 73, no. 12 (2020): 1292. http://dx.doi.org/10.1071/ch20184.

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Lewis base catalysed halofunctionalisation reactions of alkenes are well established and allow access to, among others, various oxygen containing heterocycles. By exploiting the known conversion of N-heterocyclic carbenes into the corresponding thioureas it has been possible to prepare and study a range of chiral and non-chiral Lewis base catalysts for such reactions. Although all thiourea catalysts were found to mediate bromocycloetherification and bromolactonisation reactions, they could not be achieved with enantioselectivity.

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2

Andrés, José M., Miriam Ceballos, Alicia Maestro, Isabel Sanz, and Rafael Pedrosa. "Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions." Beilstein Journal of Organic Chemistry 12 (April 1, 2016): 628–35. http://dx.doi.org/10.3762/bjoc.12.61.

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The catalytic activity of different supported bifunctional thioureas on sulfonylpolystyrene resins has been studied in the nitro-Michael addition of different nucleophiles to trans-β-nitrostyrene derivatives. The activity of the catalysts depends on the length of the tether linking the chiral thiourea to the polymer. The best results were obtained with the thiourea derived from (L)-valine and 1,6-hexanediamine. The catalysts can be used in only 2 mol % loading, and reused for at least four cycles in neat conditions. The ball milling promoted additions also worked very well.

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3

Foli, Giacomo, Cecilia Sasso D'Elia, Mariafrancesca Fochi, and Luca Bernardi. "Reversible modulation of the activity of thiourea catalysts with anions: a simple approach to switchable asymmetric catalysis." RSC Advances 6, no. 71 (2016): 66490–94. http://dx.doi.org/10.1039/c6ra12732k.

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4

Li, Mao-Lin, Jin-Han Yu, Yi-Hao Li, Shou-Fei Zhu, and Qi-Lin Zhou. "Highly enantioselective carbene insertion into N–H bonds of aliphatic amines." Science 366, no. 6468 (2019): 990–94. http://dx.doi.org/10.1126/science.aaw9939.

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Aliphatic amines strongly coordinate, and therefore easily inhibit, the activity of transition-metal catalysts, posing a marked challenge to nitrogen-hydrogen (N–H) insertion reactions. Here, we report highly enantioselective carbene insertion into N–H bonds of aliphatic amines using two catalysts in tandem: an achiral copper complex and chiral amino-thiourea. Coordination by a homoscorpionate ligand protects the copper center that activates the carbene precursor. The chiral amino-thiourea catalyst then promotes enantioselective proton transfer to generate the stereocenter of the insertion pro

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5

Vazquez-Chavez, Josué, Socorro Luna-Morales, Diego A. Cruz-Aguilar, et al. "The effect of chiral N-substituents with methyl or trifluoromethyl groups on the catalytic performance of mono- and bifunctional thioureas." Organic & Biomolecular Chemistry 17, no. 47 (2019): 10045–51. http://dx.doi.org/10.1039/c9ob01893j.

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Thiourea organocatalysts with a chiral group containing a trifluoromethyl moiety have better hydrogen bonding properties. However, not all reactions catalysed by bifunctional catalysts are enhanced by stronger NH acidity.

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6

Takemoto, Yoshiji, and Tsubasa Inokuma. "ChemInform Abstract: Bifunctional Thiourea Catalysts." ChemInform 44, no. 25 (2013): no. http://dx.doi.org/10.1002/chin.201325211.

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7

Li, Zheng-Yi, Hong-Xiao Tong, Yuan Chen, et al. "Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives." Beilstein Journal of Organic Chemistry 14 (July 25, 2018): 1901–7. http://dx.doi.org/10.3762/bjoc.14.164.

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A number of upper rim-functionalized calix[4]thiourea cyclohexanediamine derivatives have been designed, synthesized and used as catalysts for enantioselective Michael addition reactions between nitroolefins and acetylacetone. The optimal catalyst 2 with a mono-thiourea group exhibited good performance in the presence of water/toluene (v/v = 1:2). Under the optimal reaction conditions, high yields of up to 99% and moderate to good enantioselectivities up to 94% ee were achieved. Detailed experiments clearly showed that the upper rim-functionalized hydrophobic calixarene scaffold played an impo

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8

Zhang, Zhiguo, Zongbi Bao, and Huabin Xing. "N,N′-Bis[3,5-bis(trifluoromethyl)phenyl]thiourea: a privileged motif for catalyst development." Org. Biomol. Chem. 12, no. 20 (2014): 3151–62. http://dx.doi.org/10.1039/c4ob00306c.

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This review summarizes the key developments of N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea (Schreiner's thiourea)-mediated reactions with the aim to further expand the applications of (thio)urea-based catalysts.

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9

Bhaskararao, Bangaru, and Raghavan B. Sunoj. "Two chiral catalysts in action: insights into cooperativity and stereoselectivity in proline and cinchona-thiourea dual organocatalysis." Chemical Science 9, no. 46 (2018): 8738–47. http://dx.doi.org/10.1039/c8sc03078b.

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Increasing use of two chiral catalysts in cooperative asymmetric catalysis in recent years raises some fundamental questions on chiral compatibility between the catalysts, modes of activation, and relative disposition of substrates within the chiral environment of the catalysts for effective asymmetric induction.

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10

Levi, Samuel M., Qiuhan Li, Andreas R. Rötheli, and Eric N. Jacobsen. "Catalytic activation of glycosyl phosphates for stereoselective coupling reactions." Proceedings of the National Academy of Sciences 116, no. 1 (2018): 35–39. http://dx.doi.org/10.1073/pnas.1811186116.

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Glycosyl phosphates are shown to be activated to stereospecific nucleophilic substitution reactions by precisely tailored bis-thiourea catalysts. Enhanced reactivity and scope is observed with phosphate relative to chloride leaving groups. Stronger binding (Km) to the H-bond donor and enhanced reactivity of the complex (kcat) enables efficient catalysis with broad functional group compatibility under mild, neutral conditions.

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11

Deng, L., R. Singh, and B. Foxman. "Multifunctional Catalysts: Thiourea Amine Acid Salts." Synfacts 2010, no. 09 (2010): 1068. http://dx.doi.org/10.1055/s-0030-1257969.

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12

Nagy, Fehér, Dargó, et al. "Comparison of Cinchona Catalysts Containing Ethyl or Vinyl or Ethynyl Group at Their Quinuclidine Ring." Materials 12, no. 18 (2019): 3034. http://dx.doi.org/10.3390/ma12183034.

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Numerous cinchona organocatalysts with different substituents at their quinuclidine unit have been described and tested, but the effect of those saturation has not been examined before. This work presents the synthesis of four widely used cinchona-based organocatalyst classes (hydroxy, amino, squaramide, and thiourea) with different saturation on the quinuclidine unit (ethyl, vinyl, ethynyl) started from quinine, the most easily available cinchona derivative. Big differences were found in basicity of the quinuclidine unit by measuring the pKa values of twelve catalysts in six solvents. The eff

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13

Schroeder, Zachary W., L. K. Hiscock, and Louise Nicole Dawe. "Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole." Acta Crystallographica Section C Structural Chemistry 73, no. 11 (2017): 905–10. http://dx.doi.org/10.1107/s205322961701381x.

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Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N′-(pyridin-2-yl)thiourea, C13H13N3OS, and the intermediate metal complexes aq

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14

Mohamadpour, Farzaneh, та Mojtaba Lashkari. "Three-component reaction of β-keto esters, aromatic aldehydes and urea/thiourea promoted by caffeine, a green and natural, biodegradable catalyst for eco-safe Biginelli synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones derivatives under solvent-free conditions". Journal of the Serbian Chemical Society 83, № 6 (2018): 673–84. http://dx.doi.org/10.2298/jsc170712041m.

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Caffeine was found to be a natural and green and biodegradable catalyst for the one-pot, three-component condensation Biginelli reaction of ?-keto esters, aromatic aldehydes and urea/thiourea to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones/thiones derivatives under solvent-free conditions. The remarkable features of this green procedure are high yields, short reaction times, simplicity of operation and work-up procedures, the availability and easy handling of this solid catalyst, avoidance of hazardous or toxic catalysts and organic solvents and economic availability of the catalys

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15

Chowdhury, Raghunath, Mukesh Kumar, and Sunil K. Ghosh. "Organocatalyzed enantioselective Michael addition/cyclization cascade reaction of 3-isothiocyanato oxindoles with arylidene malonates." Organic & Biomolecular Chemistry 14, no. 47 (2016): 11250–60. http://dx.doi.org/10.1039/c6ob02104b.

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Both enantiomers of functionalized 3,2′-pyrrolidinyl spirooxindoles were obtainedviaa Michael-cyclization cascade reaction using pseudoenantiomeric cinchona alkaloid derived thiourea based bifunctional catalysts.

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16

Wang, Yongchao, Angel A. Cobo, and Annaliese K. Franz. "Recent advances in organocatalytic asymmetric multicomponent cascade reactions for enantioselective synthesis of spirooxindoles." Organic Chemistry Frontiers 8, no. 15 (2021): 4315–48. http://dx.doi.org/10.1039/d1qo00220a.

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17

Michigami, Kenichi, Hiroki Murakami, Takeru Nakamura, Noboru Hayama, and Yoshiji Takemoto. "Catalytic asymmetric aza-Michael addition of fumaric monoacids with multifunctional thiourea/boronic acids." Organic & Biomolecular Chemistry 17, no. 9 (2019): 2331–35. http://dx.doi.org/10.1039/c9ob00045c.

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18

Frings, Marcus, Isabelle Thomé, and Carsten Bolm. "Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis." Beilstein Journal of Organic Chemistry 8 (September 3, 2012): 1443–51. http://dx.doi.org/10.3762/bjoc.8.164.

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For the first time, chiral sulfoximine derivatives have been applied as asymmetric organocatalysts. In combination with a thiourea-type backbone the sulfonimidoyl moiety leads to organocatalysts showing good reactivity in the catalytic desymmetrization of a cyclic meso-anhydride and moderate enantioselectivity in the catalytic asymmetric Biginelli reaction. Straightforward synthetic routes provide the newly designed thiourea-sulfoximine catalysts in high overall yields without affecting the stereohomogeneity of the sulfur-containing core fragment.

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19

Puglisi, Alessandra, Maurizio Benaglia, Elisabetta Massolo, and Giuseppe Celentano. "Poly(methylhydrosiloxane)-supported chiral thiourea-based bifunctional catalysts." Recyclable Catalysis 1 (January 23, 2012): 1–5. http://dx.doi.org/10.2478/recat-2012-0001.

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20

Shim, Jae Ho, Yeonsun Hong, Ji Hae Kim, Hyeon Soo Kim, and Deok-Chan Ha. "Organocatalytic Asymmetric Michael Addition in Aqueous Media by a Hydrogen-Bonding Catalyst and Application for Inhibitors of GABAB Receptor." Catalysts 11, no. 9 (2021): 1134. http://dx.doi.org/10.3390/catal11091134.

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Catalysts based on (R, R)-1,2-diphenylethylenediamine are, as chiral organic catalysts, applied to the asymmetric Michael addition to α, β-unsaturated nitroalkenes under neutral conditions. The role of an aqueous medium for organic catalytic activity can be reversed concerning hydrophilic-hydrophobic function depending on the reaction conditions. In this study, to provide an environmentally friendly system, the thiourea-based catalyst substituted with 3,5-(CF3)2-Ph was used in water solvents. The hydrophobic effect of the substituent provided fast reaction, high chemical yield, and mirror-imag

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21

Yang, Hui, Choon-Hong Tan, and Ming Wah Wong. "In silico characterization and prediction of thiourea-like neutral bidentate halogen bond catalysts." Organic & Biomolecular Chemistry 19, no. 32 (2021): 7051–60. http://dx.doi.org/10.1039/d1ob01092a.

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Through DFT calculations, thiourea-like halogen bond (XB)-based catalysts, with XB donor moieties connected via covalent bonds, have been designed and applied to Diels–Alder reaction and sulfa-Michael addition.

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22

Chassillan, Louis, Yasuhiro Yamashita, Woo-Jin Yoo, et al. "Enantioselective hydrophosphonylation of N-Boc imines using chiral guanidine–thiourea catalysts." Organic & Biomolecular Chemistry 19, no. 48 (2021): 10560–64. http://dx.doi.org/10.1039/d1ob01953h.

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The synthesis of new guanidine-thiourea catalysts and their use for the formation of α-amino phosphonate by asymmetric hydrophosphonylation of N-Boc aldimines under batch and continous-flow conditions is described.

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23

Bai, Zhushuang, Ling Ji, Zemei Ge, Xin Wang, and Runtao Li. "Asymmetric Michael addition reactions of nitroalkanes to 2-furanones catalyzed by bifunctional thiourea catalysts." Organic & Biomolecular Chemistry 13, no. 19 (2015): 5363–66. http://dx.doi.org/10.1039/c5ob00708a.

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24

Huang, Wen-Yao, Li-Cheng Jheng, Tar-Hwa Hsieh, et al. "Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell." Polymers 12, no. 12 (2020): 3070. http://dx.doi.org/10.3390/polym12123070.

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Triethylenetetramine (TETA) and thiourea complexed Cobalt(II) (Co(II)) ions are used as cathode catalysts for proton exchanged membrane fuel cells (PEMFCs) under the protection of polyaniline (PANI) which can become a conducting medium after calcination. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra clearly reveal the presence of typical carbon nitride and sulfide bonds of the calcined Nitrogen (N)- or Sulfur (S)-doped co-catalysts. Clear (002) and (100) planes of carbon-related X-ray diffraction patterns are found for co-catalysts after calc

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25

Azad, Chandra S., Imran A. Khan, and Anudeep K. Narula. "Organocatalyzed asymmetric Michael addition by an efficient bifunctional carbohydrate–thiourea hybrid with mechanistic DFT analysis." Organic & Biomolecular Chemistry 14, no. 48 (2016): 11454–61. http://dx.doi.org/10.1039/c6ob02158a.

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A series of thiourea based bifunctional organocatalysts having d-glucose as a core scaffold were synthesized and examined as catalysts for the asymmetric Michael addition reaction of aryl/alkyl trans-β-nitrostyrenes over cyclohexanone and other Michael donors having active methylene.

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26

Lu, Jinni, and Patrick H. Toy. "Multifunctional organic polymeric catalysts and reagents." Pure and Applied Chemistry 85, no. 3 (2012): 543–56. http://dx.doi.org/10.1351/pac-con-12-04-13.

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A series of polystyrenes bearing multiple different functional groups has been synthesized, and these materials have been used as catalysts and reagents in a variety of organic reactions. Polymers functionalized with various combinations of amine, phenol, phosphine, and thiourea groups have been prepared in both non-cross-linked (soluble) and cross-linked (insoluble) formats. Reactions catalyzed by these polymers include Morita–Baylis–Hillman (MBH), alkyne to 1,3-diene isomerization, and decarboxylative Doebner–Knoevenagel reactions. Furthermore, Wittig and tandem Wittig/reduction reactions ha

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27

Kobayashi, Yusuke, and Yoshiji Takemoto. "Reactions Catalyzed by 2-Halogenated Azolium Salts: From Halogen-Bond Donors to Brønsted-Acidic Salts." Synlett 31, no. 08 (2020): 772–83. http://dx.doi.org/10.1055/s-0039-1690815.

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Our research group has developed a variety of organocatalysts, especially bi- and multi-functional hydrogen-bond (HB)-donor catalysts. Since 2013, we have become interested in halogen-bond (XB) interactions in organic synthesis, and we have focused on the development of organocatalysts using XBs. Although it is difficult to develop otherwise inaccessible transformations using XBs as the primary interaction, we found several unique reactions that use XB interactions in combination with co-catalysts such as trimethylsilyl iodide, Proton Sponge, and Schreiner’s thiourea. During the synthesis of v

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28

Hillerová, Eva, Jiří Sedláček, and Miroslav Zdražil. "Bimetallic sulphide catalysts Ni-M-Sx/SiO2 prepared by unconventional method involving thiourea complexes." Collection of Czechoslovak Chemical Communications 52, no. 7 (1987): 1748–57. http://dx.doi.org/10.1135/cccc19871748.

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An unconventional method of preparation of hydrodesulphurization catalysts was tested. A series of M-Sx/SiO2 and Ni-M-Sx/SiO2 catalysts was prepared, where M was V, Cr, Mn, Mo, W or Nb, respectively. A mixture of a salt of the metal M, thiourea, glycerol, sulphur, isopropanol, and silica gel was thermally decomposed to obtain the M-Sx/SiO2 catalysts. Nickel was deposited from solution of nickel acetate in methanol. Activity of catalysts was tested in benzothiophene hydrodesulphurization and their surface composition was characterized by XPS. The activity of samples containing Ni-Mo and Ni-W wa

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29

Li, Yun, Qing-chuan Yang, Xiao-Ying Xu, et al. "A highly asymmetric direct aldol reaction catalyzed by chiral proline amide – thiourea bifunctional catalysts." Canadian Journal of Chemistry 89, no. 10 (2011): 1312–18. http://dx.doi.org/10.1139/v11-029.

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A series of chiral proline amide – thiourea bifunctional catalysts derived from l-proline and chiral diamine were prepared and successfully applied to highly enantioselective direct aldol reactions of cyclohexanone with various aldehydes in excellent yields (85%–97%), diastereoselectivities (anti/syn > 20:1) and enantioselectivities (up to 91% ee).

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30

Yamamoto, Eiji, Kodai Wakafuji, Yusuke Mori, Gaku Teshima, Yuki Hidani, and Makoto Tokunaga. "Enantioselective Protonation of Enol Esters with Bifunctional Phosphonium/Thiourea Catalysts." Organic Letters 21, no. 11 (2019): 4030–34. http://dx.doi.org/10.1021/acs.orglett.9b01216.

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31

Tommasino, M. Lorraine, Magali Casalta, Jérémy A. J. Breuzard, and Marc Lemaire. "Asymmetric hydrogenation of enamides with catalysts containing chiral thiourea ligands." Tetrahedron: Asymmetry 11, no. 24 (2000): 4835–41. http://dx.doi.org/10.1016/s0957-4166(00)00489-4.

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32

Li, De Run, Anyu He, and J. R. Falck. "Enantioselective, Organocatalytic Reduction of Ketones using Bifunctional Thiourea-Amine Catalysts." Organic Letters 12, no. 8 (2010): 1756–59. http://dx.doi.org/10.1021/ol100365c.

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33

Fotaras, Stamatis, Christoforos G. Kokotos, Evaggelia Tsandi, and George Kokotos. "Prolinamides Bearing Thiourea Groups as Catalysts for Asymmetric Aldol Reactions." European Journal of Organic Chemistry 2011, no. 7 (2011): 1310–17. http://dx.doi.org/10.1002/ejoc.201001417.

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34

Fernandes, Eryk, Paweł Mazierski, Tomasz Klimczuk, Adriana Zaleska-Medynska, Rui C. Martins, and João Gomes. "g-C3N4 for Photocatalytic Degradation of Parabens: Precursors Influence, the Radiation Source and Simultaneous Ozonation Evaluation." Catalysts 13, no. 5 (2023): 789. http://dx.doi.org/10.3390/catal13050789.

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Graphitic carbon nitride (g-C3N4) is a promising catalyst for contaminants of emerging concern removal applications, especially as a visible-light-driven material. In this study, g-C3N4 catalysts were effectively synthesized through a simple thermal polymerization method, using melamine, urea, and thiourea as precursors to elucidate the influence of these compounds on the final product’s photocatalytic performance. The degradation of a mixture of three parabens was investigated under different types of radiation: two artificial, ultraviolet-A (UVA) and visible LED, and natural sunlight. The ur

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35

Phillips, Ana Maria Faisca, Martin H. G. Prechtl, and Armando J. L. Pombeiro. "Non-Covalent Interactions in Enantioselective Organocatalysis: Theoretical and Mechanistic Studies of Reactions Mediated by Dual H-Bond Donors, Bifunctional Squaramides, Thioureas and Related Catalysts." Catalysts 11, no. 5 (2021): 569. http://dx.doi.org/10.3390/catal11050569.

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Chiral bifunctional dual H-bond donor catalysts have become one of the pillars of organocatalysis. They include squaramide, thiosquaramide, thiourea, urea, and even selenourea-based catalysts combined with chiral amines, cinchona alkaloids, sulfides, phosphines and more. They can promote several types of reactions affording products in very high yields and excellent stereoselectivities in many cases: conjugate additions, cycloadditions, the aldol and Henry reactions, the Morita–Baylis–Hilman reaction, even cascade reactions, among others. The desire to understand mechanisms and the quest for t

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36

Mayakrishnan, Gopiraman, Kim Ick Soo, and Chung Ill Min. "Stepwise Construction of Ru(II)Center Containing Chiral Thiourea Ligand on Graphene Oxide: First Efficient, Reusable, and Stable Catalyst for Asymmetric Transfer Hydrogenation of Ketones." Catalysts 10, no. 2 (2020): 175. http://dx.doi.org/10.3390/catal10020175.

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Heterogenization of homogenous catalysts on solid support has attracted tremendous attention in organic synthesis due to the key benefits of heterogenized catalysts such as easy recovery and reusability. Although a considerable number of heterogenized catalysts are available, to the best of our knowledge, there is no efficient and reusable heterogenized catalyst reported for asymmetric reactions to date. Herein, we prepared a [RuCl2(η6-p-cymene)]/chiralthiourea ligand covalently bonded to graphene nanosheets (G-CLRu(II), where G represents graphene oxide (GO), CL denotes chiral N-((1-phenyleth

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37

Cui, Yingna, Changping Li, and Ming Bao. "Deep eutectic solvents (DESs) as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones." Green Processing and Synthesis 8, no. 1 (2019): 568–76. http://dx.doi.org/10.1515/gps-2019-0026.

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Abstract Deep eutectic solvents (DESs) are successfully used as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs). The acidity of DESs is the main factor that determines catalytic activity. DESs, based on p-toluene sulfonic acid (PTSA) and choline chloride (ChCl), exhibits the highest catalytic activity. ChCl/2PTSA is suitable for a vast variety of aromatic aldehydes with electron-donating and electron-withdrawing groups, different β-diketonates, and urea or thiourea to obtain the corresponding DHPMs. Furthermore, DESs can be re

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38

He, Leqin, Shenjun Qin, Jianjun Liu, Wei Zhao, and Tao Chang. "Long-chain Brønsted acidic ionic liquids catalyzed one-pot three-component Biginelli reaction." World Journal of Engineering 17, no. 1 (2020): 21–26. http://dx.doi.org/10.1108/wje-09-2019-0255.

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Purpose From the atom economy and environmentally friendly point of views, the development of clean and green approaches using ionic liquids (ILs) as recyclable catalysts has attracted increasing attention. The purpose of this study is to investigate the effect of task-specific ILs content on the one-pot three-component Biginelli reaction. Design/methodology/approach A series of halogen-free quaternary ammonium ILs functionalized with –SO3H group were prepared and characterized by 1H nuclear magnetic resonance (NMR), 13C NMR and electrospray ionization mass spectrometry. The ILs were used as c

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39

Vargas, Adriana, Johana Borda, and Robinson Torres. "Aqueous Pretreatment Effect to Improve Au, Ag, and Pt Recovery from Spent Automotive Catalysts." Revista Científica 47, no. 2 (2023): 116–26. http://dx.doi.org/10.14483/23448350.20875.

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Automotive catalysts represent a secondary source for precious metals recovery. These elements are usually obtained from minerals. Recently, methods have been sought to recover them from waste materials. The main route consists of pyrometallurgical treatments at high temperatures with the generation of other pollutants and very high energy consumption. With hydrometallurgy, routes can be developed which favor the aqueous extraction of said elements at room temperature. In an automotive catalyst, there are different metals which can interfere in the recovery process. In this study, sodium citra

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40

Sakakura, Akira, Yudai Fujii, Ryota Nakao, et al. "Enantioselective Diels–Alder Reaction of 3-Nitrocoumarins Promoted by Chiral Organoammonium Salt Catalysts." Synlett 31, no. 20 (2020): 2013–17. http://dx.doi.org/10.1055/s-0040-1707302.

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AbstractAn enantioselective Diels–Alder reaction of 3-nitrocoumarins has been developed. A tryptophan-derived C 1-symmetric organoammonium thiourea catalyst promoted the reaction of 3-nitrocoumarins with Danishefsky’s diene to give the corresponding adducts with good enantioselectivity (up to 94% ee). One of the resulting adducts was converted into a chiral carbocyclic quaternary β-amino alcohol.

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S. Refat, Moamen, Mohamed Y. El-Sayed, Ibrahim H. Alsohaimi, Hassan M. Hassan, Thamer S. Alraddadid, and Sultan Akhtar. "A simple and low-cost new procedure for synthesis of nickel(II) and cadmium(II) sulfides in situ thiourea metal–chelation precursor." Bulletin of the Chemical Society of Ethiopia 37, no. 3 (2023): 663–74. http://dx.doi.org/10.4314/bcse.v37i3.10.

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ABSTRACT. Nickel(II) and cadmium(II) sulfides are a promising chemical material in various advanced research areas such as solar cells, supercapacitors, catalysts, and of significant interest for their practical implementations in up to photonics and electronics. Cadmium and nickel sulfides were synthesized with stoichiometries in aqueous media at elevated temperature from Ni(NO3)2.6H2O, NiCl2.6H2O, NiSO4.6H2O, CdCl2, Cd(NO3)2.4H2O, CdSO4.8H2O and thiourea as a sulfur precursor using a direct chemical reaction. At room temperature an octahedral and tetrahedral geometries result from the reacti

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贾, 俊. "L-Proline Derived New Thiourea Catalysts Catalyzed Addition Alkylation of Benzaldehyde." Studies in Synthetic Chemistry 08, no. 01 (2020): 25–32. http://dx.doi.org/10.12677/ssc.2020.81003.

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Takemoto, Yoshiji, Hideto Miyabe, Sayo Tuchida, and Masashige Yamauchi. "Reaction of Nitroorganic Compounds Using Thiourea Catalysts Anchored to Polymer Support." Synthesis 2006, no. 19 (2006): 3295–300. http://dx.doi.org/10.1055/s-2006-950196.

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Wang, Yi, Karen L. Milkiewicz, Mildred L. Kaufman, et al. "Plant Process for the Preparation of Cinchona Alkaloid-Based Thiourea Catalysts." Organic Process Research & Development 21, no. 3 (2017): 408–13. http://dx.doi.org/10.1021/acs.oprd.7b00049.

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Mei, Y., P. A. Bentley, and J. Du. "NCS with thiourea as highly efficient catalysts for acetalization of aldehydes." Tetrahedron Letters 50, no. 29 (2009): 4199–200. http://dx.doi.org/10.1016/j.tetlet.2009.01.006.

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Elmaghraby, A. M., I. A. Mousa, A. A. Harb, and M. Y. Mahgoub. "Three Component Reaction: An Efficient Synthesis and Reactions of 3,4-Dihydropyrimidin-2(1H)-Ones and Thiones Using New Natural Catalyst." ISRN Organic Chemistry 2013 (August 18, 2013): 1–13. http://dx.doi.org/10.1155/2013/706437.

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Synthesis of 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidin-2(1H)-thione derivatives from aldehydes, 1,3-dicarbonyl derivatives and urea or thiourea using granite and quartz as new, natural and reusable catalysts. Some of the 3,4-dihydropyrimidin-2(1H)-thione derivatives were used to prepare new heterocyclic compounds. The antimicrobial activity of selected examples of the synthesized compounds was tested and showed moderate activity.

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Zielińska-Błajet, Mariola, and Joanna Najdek. "Novel Selenoureas Based on Cinchona Alkaloid Skeleton: Synthesis and Catalytic Investigations." Materials 14, no. 3 (2021): 600. http://dx.doi.org/10.3390/ma14030600.

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An efficient approach to the synthesis of chiral selenoureas consisting of Cinchona alkaloid scaffolds was described. The new selenoureas were assessed as bifunctional organocatalysts in the asymmetric Michael addition reactions under mild conditions. The best results were obtained for selenoureas bearing the 4-fluorophenyl group. These catalysts promoted the reactions with enantioselectivities of up to 96% ee. Additionally, the catalytic performance of the thiourea and selenourea counterpart was compared.

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Jawore, A. M., T. Xaba, and M. J. Moloto. "(Z)-2-(pyrrolidin-2-ylidene) thiourea based nickel (II) complex as a single source precursor for the synthesis of NiS nanoparticles and thin films." Chalcogenide Letters 20, no. 7 (2023): 497–505. http://dx.doi.org/10.15251/cl.2023.207.497.

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Nickel sulfides nanocrystals may be regarded as promising of materials in different research areas such as catalysts, solar cells, and electrode-materials. (Z)-2-(pyrrolidin-2-ylidene) thiourea ligand and (Z)-2-(pyrrolidin-2-ylidene) thiourea based nickel (II) complex have been prepared and utilized as single source molecular precursor for the synthesis of nickel sulfide nanoparticles and thin films. The effect of temperature was studies during the synthetic processes. The synthesized nanomaterials were characterized with various instruments. UV-Vis spectroscopy results of the nanoparticles we

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Xia, Pengfei, Guojing Li, Xiaowei Li, et al. "Synthesis of g-C3N4 from Various Precursors for Photocatalytic H2 Evolution under the Visible Light." Crystals 12, no. 12 (2022): 1719. http://dx.doi.org/10.3390/cryst12121719.

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Graphitic carbon nitride (g-C3N4) fabricated from different precursors exhibits unique microstructures and photocatalytic performance under visible light. Herein, we synthesized five different microstructures of g-C3N4 by the thermal poly condensation method using guanidine hydrochloride, melamine, urea, dicyandiamide and thiourea as the precursors. The results indicated that g-C3N4 prepared from urea precursor (UCN) has a nanostructure, porous layered structure, large specific surface area, and high separation efficiency of photo generated hole-electron pairs, which showed the best photocatal

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Quan, Zheng-Jun, Xi-Cun Wang, Zheng-He Zhu, Ming-Zhe Ren, and Bao-Qian Cao. "Metal- and Oxidant-Free Electrochemical Oxidative Desulfurization C–O Coupling of Thiourea-Type Compounds with Alcohols." Synthesis 52, no. 11 (2020): 1634–42. http://dx.doi.org/10.1055/s-0039-1690837.

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An efficient desulfurization C–O coupling reaction of 3,4-dihydropyrimidine-2(1H)-thiones (including thioureas) with alcohols was developed under electrochemical oxidation conditions. Herein, transition-metal catalysts and additives are not required and the alcohol is both the solvent and the alkoxy donor.

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