Zeitschriftenartikel: „Organic reaction methodology“

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Chinchilla, Rafael, und Carmen Nájera. „The Sonogashira Reaction: A Booming Methodology in Synthetic Organic Chemistry†“. Chemical Reviews 107, Nr. 3 (März 2007): 874–922. http://dx.doi.org/10.1021/cr050992x.

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Sharma, Sulekha. „Electro-organic Reactions: Direct and Indirect Electrolysis“. Oriental Journal Of Chemistry 40, Nr. 2 (30.04.2024): 321–32. http://dx.doi.org/10.13005/ojc/400202.

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Electro-organic synthesis is a new methodology for synthesizing organic molecules, which helped overcome the use of toxic oxidants and expensive catalysts and make the reaction greener. The fundamental concepts of electrochemistry involve simple oxidation and reduction reactions, where electrons act as the greener oxidant and reductant. This review discusses electrochemical principles and basic terminologies that find their roots in physical organic chemistry to influence a spectrum of organic and inorganic reactions. This review also discusses the different modes of electrolysis, i.e., direct and indirect. Finally, the review highlights the importance of direct and indirect electrolysis for various reactions.

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Noor, Rida, Ameer Fawad Zahoor, Muhammad Irfan, Syed Makhdoom Hussain, Sajjad Ahmad, Ali Irfan, Katarzyna Kotwica-Mojzych und Mariusz Mojzych. „Transition Metal Catalyzed Hiyama Cross-Coupling: Recent Methodology Developments and Synthetic Applications“. Molecules 27, Nr. 17 (02.09.2022): 5654. http://dx.doi.org/10.3390/molecules27175654.

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Hiyama cross-coupling is a versatile reaction in synthetic organic chemistry for the construction of carbon–carbon bonds. It involves the coupling of organosilicons with organic halides using transition metal catalysts in good yields and high enantioselectivities. In recent years, hectic progress has been made by researchers toward the synthesis of diversified natural products and pharmaceutical drugs using the Hiyama coupling reaction. This review emphasizes the recent synthetic developments and applications of Hiyama cross-coupling.

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Lei, Ming, Qingtong Zhang, Douyong Min und Shuangfei Wang. „The Treatment of Absorbable Organic Halogens and Organic Compounds in Simulated Bleaching Effluents Through the Response Surface Methodology Optimized Fenton System“. Journal of Biobased Materials and Bioenergy 14, Nr. 2 (01.04.2020): 280–86. http://dx.doi.org/10.1166/jbmb.2020.1949.

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In this study, the effects of four main factors on the removal of absorbable organic halogens were evaluated by response surface methodology, and the changes of absorbable organic halogens components were characterized by gas chromatography-mass spectrometer during the Fenton reaction. The high regression coefficient (R2 = 0.9028) and the low coefficient of variation (7.45%) indicated that the model was accurate in predicting the experimental results. The optimized pH, Fe2+ concentration, molar ratio of H2O2/Fe2+ and reaction time were respectively 3.4, 16.3 mM, 22.5 and 1.2 h. Consequently, 93.8% of absorbable organic halogens were removed under the optimized condition. The initial pH is the most important factor impacting the absorbable organic halogens removal. Furthermore, gas chromatography-mass spectrometer revealed that 25 out of 28 organic compounds including 7 absorbable organic halogens were thoroughly removed. Conclusively, Fenton reaction can effectively remove absorbable organic halogens from the simulated bleaching effluent.

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Jimenez, David Esteban Quintero, Lucas Lima Zanin, Luan Farinelli Diniz, Javier Ellena und André Luiz Meleiro Porto. „Green Synthetic Methodology of (E)-2-cyano-3-aryl Selective Knoevenagel Adducts Under Microwave Irradiation“. Current Microwave Chemistry 6, Nr. 1 (24.10.2019): 54–60. http://dx.doi.org/10.2174/2213335606666190906123431.

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Background: The Knoevenagel condensation is an important reaction in organic chemistry because of its capacity to form new C-C bonds and its products are mainly used in organic synthesis as intermediates, due to the large number of reactions they can undergo. Based on the importance of the Knoevenagel adducts, a sustainable synthetic methodology was developed employing microwave irradiation. Objective: Develop a synthetic methodology employing microwave irradiation and green solvents to obtain Knoevenagel adducts with high yields. Methods: Knoevenagel condensation reactions were evaluated with different basic catalysts, as well as in the presence or absence of microwave irradiation. The scope of the reaction was expanded using different aldehydes, cyanoacetamide or methyl cyanoacetate. The geometry of the formed products was also evaluated. Results: After the optimization process, the reactions between aldehydes and cyanoacetamide were performed with triethylamine as catalyst, in the presence of microwave irradiation, in 35 minutes, using NaCl solution as solvent and resulted in high yields 90-99%. The reactions performed between aldehydes and methyl cyanoacetate were also performed under these conditions, but showed better yields with EtOH as solvent 70-90%. Finally, from X-ray analysis, the (E)-geometry of these compounds was confirmed. Conclusion: In this study we developed synthetic methodology of Knoevenagel condensation using triethylamine, green solvents and microwave irradiation. In 35 minutes, products with high yields (70- 99%) were obtained and the (E)-geometry of the adducts was confirmed.

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Lei, Jie, Jia Xu, Dian-Yong Tang, Jing-Wei Shao, Hong-yu Li, Zhong-Zhu Chen und Zhi-Gang Xu. „A concise and unexpected one-pot methodology for the synthesis of pyrazinone-fused pyridones“. Organic Chemistry Frontiers 7, Nr. 18 (2020): 2657–63. http://dx.doi.org/10.1039/d0qo00590h.

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A post-Ugi/Michael/Retro-Michael reaction, aromatization and 5-exo-dig cyclization cascade reaction was developed and utilized for the synthesis of pyrazinone-fused pyridone derivatives under mild reaction conditions in one-pot.

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Hakkou, H., D. Carrié, L. Paquin und J. P. Bazureau. „Ionic liquid-phase organic synthesis (IoLiPOS) methodology applied to cross aldol reaction“. Russian Journal of Organic Chemistry 47, Nr. 3 (März 2011): 371–73. http://dx.doi.org/10.1134/s1070428011030079.

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Reddy, K. Sateesh, Bandi Siva, S. Divya Reddy, N. Reddy Naresh, T. V. Pratap, B. Venkateswara Rao, Yi-An Hong et al. „In Situ FTIR Spectroscopic Monitoring of the Formation of the Arene Diazonium Salts and Its Applications to the Heck–Matsuda Reaction“. Molecules 25, Nr. 9 (08.05.2020): 2199. http://dx.doi.org/10.3390/molecules25092199.

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This study depicts the use of a fiber-optic coupled Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) probe for the in-depth study of arene diazonium salt formation and their utilization in the Heck–Matsuda reaction. The combination of these chemical reactions and in situ IR spectroscopy enabled us to recognize the optimum parameters for arene diazonium salt formation and to track the concentrations of reactants, products and intermediates under actual reaction conditions without time consuming HPLC analysis and the necessity of collecting the sample amid the reaction. Overall advantages of the proposed methodology include precise reaction times as well as identification of keto enol tautomerization in allylic alcohols supporting the ‘path a’ elimination mechanism in the Heck–Matsuda reaction.

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Radhika, Sankaran, Mohan Neetha, Thaipparambil Aneeja und Gopinathan Anilkumar. „Microwave-assisted Amination Reactions: An Overview“. Current Organic Chemistry 24, Nr. 19 (01.12.2020): 2235–55. http://dx.doi.org/10.2174/1385272824999200914111246.

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C-N coupling reactions were found to be attractive among researchers owing to the importance of C-N bond formation in heterocyclic synthesis. Hence C-N bond formation via amination reaction with the assistance of microwave radiations gained significant attraction recently. Microwave-assisted reactions are greener, faster and generally efficient compared to the conventional thermal reactions offering better purity of the product with enhancement in the yield. It was surprisingly revealed that several new advancements in amination reactions were highly influenced by this greener technology. This first review on microwave-assisted amination reaction focuses on the novel amination strategies that emerged with the help of microwave methodology, and covers literature up to 2019.

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Roy, Snigdha. „Prins-Friedel-Crafts Cyclization: Synthesis of Diversely Functionalized Six- Membered Oxacycles“. Current Organic Chemistry 25, Nr. 5 (15.03.2021): 635–51. http://dx.doi.org/10.2174/1385272825666210114105020.

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Prins cyclization is a well-established synthetic protocol to generate a wide range of important oxygen heterocycles. It is a cyclization reaction performed by an oxocarbenium ion that undergoes an intramolecular pi-bond attack to construct a new carbon-carbon bond. When this cyclization process is conjugated with Friedel-Crafts reaction, it further expands the synthetic potential by fabricating two different carbon-carbon bonds in one single reaction. Different acid catalysts mediated the coupled Prins-Friedel-Crafts reaction which is conducted both in stepwise as well as in tandem fashion. In the stepwise route, three different reacting components were utilized whereas, the tandem methodology required proper modification of the initial substrate molecule. An array of allylic, propargylic, other related alkenols, and carbonyl reactants were employed to carry out the cyclization process. Several oxygenated heterocycles equipped with diverse functionalities were constructed in a stereoselective manner which again reinforced the significance of this cyclization protocol undoubtedly. The present mini-review highlights the utilization of different one-pot stepwise Prins-Friedel-Crafts reactions and the subsequent development of cascade Prins- Friedel-Crafts cyclization process to furnish intricate molecular architectures of vital six-membered oxacycles.

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Sukhorukov, Alexey Yu. „Interrupted Nef and Meyer Reactions: A Growing Point for Diversity-Oriented Synthesis Based on Nitro Compounds“. Molecules 28, Nr. 2 (10.01.2023): 686. http://dx.doi.org/10.3390/molecules28020686.

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The Nef reaction (nitro to carbonyl group conversion) and related Meyer reaction are among the key transformations of aliphatic nitro compounds. The interrupted versions of these reactions in which the normal pathway is redirected to a different end product by an external nucleophile are much less common, albeit these processes substantially increase the synthetic potential of nitro compounds. In this review, examples of interrupted Nef and Meyer reactions are summarized, and the prospects of this methodology in diversity-oriented organic synthesis are analyzed. The bibliography contains 90 references.

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Crespo, Lívia T. C., Mônica R. Senra, Pierre M. Esteves und Marcio C. S. de Mattos. „Tribromoisocyanuric Acid as a Green Cohalogenating Reagent: An Efficient Transformation of Alkynes into α,α-Dibromoketones and Vicinal Dibromoalkenes“. Letters in Organic Chemistry 16, Nr. 8 (18.06.2019): 627–32. http://dx.doi.org/10.2174/1570178615666180803152951.

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The co-halogenation reaction of alkynes with tri-bromoisocyanuric acid in acetic acid, followed by aqueous work-up produced α,α-di-bromoketones (44-84%), while the reaction in aqueous acetonitrile in the presence of KBr produced vicinal di-bromoalkenes (66-86%). The usefulness of the methodology was demonstrated employing green metrics for the comparison of TBCA with analogous N-halo reagents in co-halogenation reactions of alkynes.

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Cimarelli, Cristina, Samuele Bordi, Pamela Piermattei, Maura Pellei, Fabio Del Bello und Enrico Marcantoni. „An Efficient Lewis Acid Catalyzed Povarov Reaction for the One-Pot Stereocontrolled Synthesis of Polyfunctionalized Tetrahydroquinolines“. Synthesis 49, Nr. 24 (07.09.2017): 5387–95. http://dx.doi.org/10.1055/s-0036-1589104.

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An easy and efficient synthetic methodology for the one-pot stereocontrolled synthesis of tetrahydroquinolines through Lewis acid activated Povarov reaction is described. The protocol takes advantage of the very cheap, easy to handle, and environmentally friendly cerium trichloride as catalyst and allows to obtain either the anti- or the syn-isomer of the final tetrahydroquinoline with good selectivity, by performing the reaction in solvent or solventless conditions. The scope of the reaction is expanded to the one-pot synthesis of N-alkyltetrahydroquinolines through a very efficient iminium-Povarov approach. A deeper insight on the reaction system was provided by the study on the side reactions occurring in the reaction conditions and on the nature of the stereoselectivity.

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Roesner, Stefan, und Varinder K. Aggarwal. „Enantioselective synthesis of (R)-tolterodine using lithiation/borylation–protodeboronation methodology“. Canadian Journal of Chemistry 90, Nr. 11 (November 2012): 965–74. http://dx.doi.org/10.1139/v2012-069.

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The synthesis of the pharmaceutical (R)-tolterodine is reported using lithiation/borylation–protodeboronation of a homoallyl carbamate as the key step. This step was tested with two permutations: an electron-neutral aryl Li-carbamate reacting with an electron-rich boronic ester and an electron-rich aryl Li-carbamate reacting with an electron-neutral boronic ester. It was found that the latter arrangement was considerably better than the former. Further improvements were achieved using magnesium bromide in methanol leading to a process that gave high yield and high enantioselectivity in the lithiation/borylation reaction. The key step was used in an efficient synthesis of (R)-tolterodine in a total of eight steps in a 30% overall yield and 90% ee.

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Liu, Li, Yue Li, Tiao Huang, Dulin Kong und Mingshu Wu. „A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids“. Beilstein Journal of Organic Chemistry 17 (07.09.2021): 2321–28. http://dx.doi.org/10.3762/bjoc.17.150.

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A novel method for the synthesis of 3-monohalooxindoles by acidolysis of isatin-derived 3-phosphate-substituted oxindoles with haloid acids was developed. This synthetic strategy involved the preparation of 3-phosphate-substituted oxindole intermediates and SN1 reactions with haloid acids. This new procedure features mild reaction conditions, simple operation, good yield, readily available and inexpensive starting materials, and gram-scalability.

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Cao, Liwei, Mikhail Kabeshov, Steven V. Ley und Alexei A. Lapkin. „In silico rationalisation of selectivity and reactivity in Pd-catalysed C–H activation reactions“. Beilstein Journal of Organic Chemistry 16 (25.06.2020): 1465–75. http://dx.doi.org/10.3762/bjoc.16.122.

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A computational approach has been developed to automatically generate and analyse the structures of the intermediates of palladium-catalysed carbon–hydrogen (C–H) activation reactions as well as to predict the final products. Implemented as a high-performance computing cluster tool, it has been shown to correctly choose the mechanism and rationalise regioselectivity of chosen examples from open literature reports. The developed methodology is capable of predicting reactivity of various substrates by differentiation between two major mechanisms – proton abstraction and electrophilic aromatic substitution. An attempt has been made to predict new C–H activation reactions. This methodology can also be used for the automated reaction planning, as well as a starting point for microkinetic modelling.

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Hopkins, Megan, Zachary Brandeburg, Andrew Hanson und Angus Lamar. „Visible-Light, Iodine-Promoted Formation of N-Sulfonyl Imines and N-Alkylsulfonamides from Aldehydes and Hypervalent Iodine Reagents“. Molecules 23, Nr. 8 (24.07.2018): 1838. http://dx.doi.org/10.3390/molecules23081838.

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Alternative synthetic methodology for the direct installation of sulfonamide functionality is a highly desirable goal within the domain of drug discovery and development. The formation of synthetically valuable N-sulfonyl imines from a range of aldehydes, sulfonamides, and PhI(OAc)2 under practical and mild reaction conditions has been developed. According to mechanistic studies described within, the reaction proceeds through an initial step involving a radical initiator (generated either by visible-light or heat) to activate the reacting substrates. The reaction provides a synthetically useful and operationally simple, relatively mild alternative to the traditional formation of N-sulfonyl imines that utilizes stable, widely available reagents.

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da Silva, Caren D. G., Ramesh Katla, Beatriz F. dos Santos, José M. C. Tavares Junior, Tábata B. Albuquerque, Vicente L. Kupfer, Andrelson W. Rinaldi und Nelson L. C. Domingues. „Cobalt Used as a Novel and Reusable Catalyst: A New and One-Pot Synthesis of Isatin-Derived N,S-Acetals Using Substituted Isatins and Thiols“. Synthesis 51, Nr. 21 (21.08.2019): 4014–22. http://dx.doi.org/10.1055/s-0037-1611913.

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The synthesis of isatin-derived N,S-acetals using cobalt as a recyclable heterogeneous catalyst in batch and continuous flow is reported for the first time. The present protocol produced high yields, which can be observed from the reaction between ketimines and thiols. Such reactions can also be applied to a gram-scale. In addition, the catalyst is recyclable, economically-viable, and nontoxic as well as easy to prepare. The remarkable features of this new methodology are high conversion and cleaner reaction profiles.

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Rossi, Laura I., und Manuel I. Velasco. „Alternatives to free molecular halogens as chemoselective reactants: Catalysis of organic reactions with reusable complexes of halogen metal salts“. Pure and Applied Chemistry 84, Nr. 3 (06.02.2012): 819–26. http://dx.doi.org/10.1351/pac-con-11-07-13.

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Organometallic complexes of halogen metallic salts have been used as catalysts in different organic reactions, mainly the oxidation of organic compounds. Their use has not only allowed the reduction of the amounts of catalyst (since they can be reused) but also a lower generation of byproducts and wastes. The different reaction media developed through the research were analyzed by several green parameters, and the best results were obtained with complexes that have cyclodextrins as organic ligands. The proposed methodology is an alternative to use of molecular halogen as oxidant or catalyst when halogens are significant chemoselective reactants.

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Havránková, Eva, Jozef Csöllei und Pavel Pazdera. „New Approach for the One-Pot Synthesis of 1,3,5-Triazine Derivatives: Application of Cu(I) Supported on a Weakly Acidic Cation-Exchanger Resin in a Comparative Study“. Molecules 24, Nr. 19 (05.10.2019): 3586. http://dx.doi.org/10.3390/molecules24193586.

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An efficient and simple methodology for Ullmann Cu(I)-catalyzed synthesis of di- and trisubstituted 1,3,5-triazine derivatives from dichlorotriazinyl benzenesulfonamide and corresponding nucleophiles is reported. Cations Cu(I) supported on macroporous and weakly acidic, low-cost industrial resin of polyacrylate type were used as a catalyst. The reaction times and yields were compared with traditional synthetic methods for synthesis of substituted 1,3,5-triazine derivatives via nucleophilic substitution of chlorine atoms in dichlorotriazinyl benzenesulfonamide. It was found that Ullmann-type reactions provide significantly shortened reaction times and, in some cases, also higher yields. Finally, trisubstituted s-triazine derivatives were effectively prepared via Ullmann-type reaction in a one-pot synthetic design. Six new s-triazine derivatives with potential biological activity were prepared and characterized.

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Yusof, Nurul Atikah Amin, Nursyamsyila Mat Hadzir, Siti Efliza Ashari, Nor Suhaila Mohamad Hanapi und Rossuriati Dol Hamid. „Optimization of Enzymatic Synthesis of Betulinic Acid Amide in Organic Solvent by Response Surface Methodology (RSM)“. Indonesian Journal of Chemistry 19, Nr. 4 (13.08.2019): 849. http://dx.doi.org/10.22146/ijc.34903.

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Optimization of the lipase catalyzed enzymatic synthesis of betulinic acid amide in the presence of immobilized lipase, Novozym 435 from Candida antartica as a biocatalyst was studied. Response surface methodology (RSM) and 5-level-4-factor central-composite rotatable design (CCRD) were employed to evaluate the effects of the synthesis parameters, such as reaction time (20–36 h), reaction temperature (37–45 °C), substrate molar ratio of betulinic acid to butylamine (1:1–1:3), and enzyme amounts (80–120 mg) on the percentage yield of betulinic acid amide by direct amidation reaction. The optimum conditions for synthesis were: reaction time of 28 h 33 min, reaction temperature of 42.92 °C, substrate molar ratio of 1:2.21, and enzyme amount of 97.77 mg. The percentage yield of actual experimental values obtained 65.09% which compared well with the maximum predicted value of 67.23%. The obtained amide was characterized by GC, GCMS and 13C NMR. Betulinic acid amide (BAA) showed a better cytotoxicity compared to betulinic acid as the concentration inhibited 50% of the cell growth (IC50) against MDA-MB-231 cell line (IC50 < 30 µg/mL).

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Leyva, Elisa, Denisse de Loera, Claudia G. Espinosa-González und Saúl Noriega. „Physicochemical Properties and Photochemical Reactions in Organic Crystals“. Current Organic Chemistry 23, Nr. 3 (09.05.2019): 215–55. http://dx.doi.org/10.2174/1385272822666190313152105.

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Background: Molecular organic photochemistry is concerned with the description of physical and chemical processes generated upon the absorption of photons by organic molecules. Recently, it has become an important part of many areas of science: chemistry, biology, biochemistry, medicine, biophysics, material science, analytical chemistry, among others. Many synthetic chemists are using photochemical reactions in crystals to generate different types of organic compounds since this methodology represents a green chemistry approach. Objective & Method: Chemical reactions in crystals are quite different from reactions in solution. The range of organic solid state reactions and the degree of control which could be achieved under these conditions are quite wider and subtle. Therefore, for a large number of molecular crystals, the photochemical outcome is not the expected product based on topochemical principles. To explain these experimental results, several physicochemical factors in crystal structure have been proposed such as defects, reaction cavity, dynamic preformation or photoinduced lattice instability and steric compression control. In addition, several crystal engineering strategies have been developed to bring molecules into adequate orientations with reactive groups in good proximity to synthesize complex molecules that in many cases are not available by conventional methods. Some strategies involve structural modifications like intramolecular substitution with different functional groups to modify intermolecular interactions. Other strategies involve chemical techniques such as mixed crystal formation, charge transfer complexes, ionic and organometallic interactions. Furthermore, some examples of the single crystal to single crystal transformations have also been developed showing an elegant method to achieve regio and stereoselectivity in a photochemical reaction. Conclusion: The several examples given in this review paper have shown the wide scope of photochemical reactions in organic molecular crystals. There are several advantages of carrying photochemical reaction in the solid state. Production of materials unobtainable by the traditional solution phase reactions, improved specificity, reduction of impurities, and enhancement in the yields by the reduction of side reactions. These advantages and the multidisciplinary nature of solid-state photochemistry make this discipline quite likely to develop a lot in the future.

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Cozzi, Pier Giorgio, Alessandro Mignogna und Luca Zoli. „Catalytic enantioselective Reformatsky reactions“. Pure and Applied Chemistry 80, Nr. 5 (01.01.2008): 891–901. http://dx.doi.org/10.1351/pac200880050891.

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The Reformatsky reaction is a venerable named reaction that was introduced more than 120 years ago. Diastereoselective variants based on the use of chiral auxiliary and enantioselective protocols, based on the employment of stoichiometric amount of chiral ligands, have been successfully applied in organic synthesis during the years. However, a facile and general catalytic enantioselective variant was still a difficult task. Recently, we have established a new general and straightforward methodology for catalytic enantioselective Reformatsky reaction based on different concepts. In this paper, we present our general finding in catalytic enantioselective Reformatsky reaction of ketones, imines, and aldehydes. Our simple methodologies could become benchmark reactions for testing new synthesized chiral ligands for asymmetric transformations.

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Escalante, Froylán, Alejandra Carranza-Hernández, Adelina García-Zamora und Efrén Aguilar-Garnica. „Optimization of Lignin-Based Biocatalyst Production from Pine Sawdust and Wheat Straw“. Molecules 23, Nr. 8 (27.07.2018): 1877. http://dx.doi.org/10.3390/molecules23081877.

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Pine sawdust and wheat straw are abundant lignocellulosic wastes that have been recently converted into bioethanol under a biochemical platform scheme whose main waste is lignin. Lignin can be transformed into a wide variety of high added-value products, including its functionalization as a catalyst. A key step in the synthesis of a lignin-based catalyst is the sulfonation reaction, whose operating conditions, namely, H2SO4 to lignin ratio (mL/g), temperature and time, have been arbitrarily chosen. In this contribution, an optimization methodology (i.e., Box-Behnken) is applied in order to found the operating conditions during the sulfonation reaction that maximizes the total acid sites density of lignin-based catalysts from pine sawdust and wheat straw. The optimization results show that the time in sulfonation reactions can be significantly reduced, compared to those previously reported, without affecting the performance of both catalysts in esterification reactions. These results could be further considered for energy and costs reduction purposes during the conceptual design engineering of the sulfonation reaction.

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Yoshida, Jun-ichi, Heejin Kim, Hyune-Jea Lee, Daiki Torii und Yongju Jeon. „Integrated Synthesis Using Isothiocyanate-Substituted Aryllithiums by Flow Chemistry“. Synlett 31, Nr. 19 (21.08.2020): 1899–902. http://dx.doi.org/10.1055/s-0040-1707251.

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The isothiocyanate (NCS) group is an attractive functional group in the field of organic and pharmaceutical chemistry. It can be transformed into other heteroatomic functional groups. It usually acts as the inductive group of biological activity and has also been traditionally used as the fluorescent-labeling reagent. However, it is not compatible with strong bases. When the NCS group is at para position in halobenzenes, it generally undergoes nucleophilic additions upon reaction with strong bases. To the best of our knowledge, there is currently no general methodology for the formation and reactions of NCS-functionalized aryllithiums for meta and para substituents. Herein, we report the continuous-flow generation of NCS-substituted aryllithiums from the corresponding haloarenes via a selective halogen–lithium exchange reaction and its reaction with various electrophiles to yield NCS-containing products. We also achieved an integrated synthesis through sequential reactions of the NCS-containing compounds with additional nucleophiles using the continuous-flow reactors.

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Ruini, Chiara, Erika Ferrari, Caterina Durante, Giulia Lanciotti, Paolo Neri, Anna Maria Ferrari und Roberto Rosa. „Integrated Approach of Life Cycle Assessment and Experimental Design in the Study of A Model Organic Reaction: New Perspectives in Renewable Vanillin-Derived Chemicals“. Molecules 29, Nr. 9 (03.05.2024): 2132. http://dx.doi.org/10.3390/molecules29092132.

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This work is focused on performing a quantitative assessment of the environmental impacts associated with an organic synthesis reaction, optimized using an experimental design approach. A nucleophilic substitution reaction was selected, employing vanillin as the substrate, a phenolic compound widely used in the food industry and of pharmaceutical interest, considering its antioxidant and antitumoral potential. To carry out the reaction, three different solvents have been chosen, namely acetonitrile (ACN), acetone (Ace), and dimethylformamide (DMF). The syntheses were planned with the aid of a multivariate experimental design to estimate the best reaction conditions, which simultaneously allow a high product yield and a reduced environmental impact as computed by Life Cycle Assessment (LCA) methodology. The experimental results highlighted that the reactions carried out in DMF resulted in higher yields with respect to ACN and Ace; these reactions were also the ones with lower environmental impacts. The multilinear regression models allowed us to identify the optimal experimental conditions able to guarantee the highest reaction yields and lowest environmental impacts for the studied reaction. The identified optimal experimental conditions were also validated by experimentally conducting the reaction in those conditions, which indeed led to the highest yield (i.e., 93%) and the lowest environmental impacts among the performed experiments. This work proposes, for the first time, an integrated approach of DoE and LCA applied to an organic reaction with the aim of considering both conventional metrics, such as reaction yield, and unconventional ones, such as environmental impacts, during its lab-scale optimization.

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Kanwal, Iram, Aqsa Mujahid, Nasir Rasool, Komal Rizwan, Ayesha Malik, Gulraiz Ahmad, Syed Adnan Ali Shah, Umer Rashid und Nadiah Mad Nasir. „Palladium and Copper Catalyzed Sonogashira cross Coupling an Excellent Methodology for C-C Bond Formation over 17 Years: A Review“. Catalysts 10, Nr. 4 (20.04.2020): 443. http://dx.doi.org/10.3390/catal10040443.

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Sonogashira coupling involves coupling of vinyl/aryl halides with terminal acetylenes catalyzed by transition metals, especially palladium and copper. This is a well known reaction in organic synthesis and plays a role in sp2-sp C-C bond formations. This cross coupling was used in synthesis of natural products, biologically active molecules, heterocycles, dendrimers, conjugated polymers and organic complexes. This review paper focuses on developments in the palladium and copper catalyzed Sonogashira cross coupling achieved in recent years concerning substrates, different catalyst systems and reaction conditions.

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Yaseen, Muhammad, Zahid Farooq, Mian H. R. Mahmood, Sheikh Asrar Ahmad, Shahbaz Nazir, Khalid Mahmood Anjum und Syed Ali Raza Naqvi. „Synthesis of Novel Symmetric Porphyrin Schiff Base Dimers by Solid–Liquid Reaction Methodology“. Journal of Heterocyclic Chemistry 56, Nr. 5 (02.04.2019): 1520–29. http://dx.doi.org/10.1002/jhet.3526.

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29

Mondal, Dipayan, Pankaj Lal Kalar, Shivam Kori, Shovanlal Gayen und Kalpataru Das. „Recent Developments on Synthesis of Indole Derivatives Through Green Approaches and Their Pharmaceutical Applications“. Current Organic Chemistry 24, Nr. 22 (18.12.2020): 2665–93. http://dx.doi.org/10.2174/1385272824999201111203812.

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Indole moiety is often found in different classes of pharmaceutically active molecules having various biological activities including anticancer, anti-viral, anti-psychotic, antihypertensive, anti-migraine, anti-arthritis and analgesic activities. Due to enormous applications of indole derivatives in pharmaceutical chemistry, a number of conventional synthetic methods as well as green methodology have been developed for their synthesis. Green methodology has many advantages including high yields, short reaction time, and inexpensive reagents, highly efficient and environmentally benign over conventional methods. Currently, the researchers in academia as well as in pharmaceutical industries have been developing various methods for the chemical synthesis of indole based compounds via green approaches to overcome the drawbacks of conventional methods. This review reflects the last ten years developments of the various greener methods for the synthesis of indole derivatives by using microwave, ionic liquids, water, ultrasound, nanocatalyst, green catalyst, multicomponent reaction and solvent-free reactions etc. (please see the scheme below). Furthermore, the applications of green chemistry towards developments of indole containing pharmaceuticals and their biological studies have been represented in this review.

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30

Yoda, Hidemi, Tetsuya Sengoku, Yuichiro Nagai und Toshiyasu Inuzuka. „New Synthetic Methodology Toward Azaspiro-γ-Lactones by Oxidative C–H Spirocyclization“. Synlett 30, Nr. 02 (17.12.2018): 199–202. http://dx.doi.org/10.1055/s-0037-1611941.

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A new synthetic methodology for azaspiro-γ-lactones is reported. The key C–H spirolactonization was accomplished by employing iodobenzene diacetate and potassium bromide to afford a variety of azaspiro-γ-lactones in high yields. The reaction was also applicable to the preparation of a bislactone derivative.

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31

Hakkou, H., D. Carrie, L. Paquin und J. P. Bazureau. „ChemInform Abstract: Ionic Liquid-Phase Organic Synthesis (IoLiPOS) Methodology Applied to Cross Aldol Reaction.“ ChemInform 42, Nr. 34 (28.07.2011): no. http://dx.doi.org/10.1002/chin.201134024.

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32

Harrington, David A. „Theory of electrochemical impedance of surface reactions: second-harmonic and large-amplitude response“. Canadian Journal of Chemistry 75, Nr. 11 (01.11.1997): 1508–17. http://dx.doi.org/10.1139/v97-181.

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The theory for the electrochemical impedance of surface reactions involving a single adsorbed species is presented. A new methodology is used, in which many harmonics are considered, and the differential equations are reduced to algebraic matrix equations. The amplitude of the ac potential perturbation is not assumed to be small, and nonlinear effects are taken into account. The amplitude dependence of the impedance and the second-harmonic response are investigated. The quasi-reversible electrosorption reaction and the hydrogen evolution reaction are considered in detail, assuming that the adsorbed species obeys the Langmuir isotherm. Keywords: electrochemistry, impedance, adsorption, hydrogen evolution reaction, second harmonic.

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33

Nacher-Luis, Anna, und Isidro M. Pastor. „1-(3,4-Dimethoxyphenyl)-3-(4-methoxyphenyl)-3-(1H-1,2,4-triazol-1-yl)propan-1-one“. Molbank 2024, Nr. 1 (12.03.2024): M1791. http://dx.doi.org/10.3390/m1791.

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The study of new catalytic protocols for the synthesis of organic compounds with a more sustainable perspective is of interest. The use of ionic organic solids, such as 1,3-bis(carboxymethyl)imidazolium chloride as a catalyst has allowed the Michael addition of N-heterocycles to chalcones. This methodology has been applied to the unique preparation of the potential bioactive compound 1-(3,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-3-(1H-1,2,4-triazol-1-yl)propan-1-one with moderate yield, due to the retro-Michael reaction. Both synthetic reactions (i.e., preparation of chalcone and triazole Michael-addition to chalcone) have good green metrics.

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34

Chen, Lianfen, Chaoyi Zhao, Weixian Mo, Chunsheng Li und Xiaoming Lin. „X-H Bond Insertion Promoted by Heterogeneous Dirhodium Metal–Organic Cage with Alkynes as Safe Carbene Precursors“. Molecules 28, Nr. 2 (06.01.2023): 608. http://dx.doi.org/10.3390/molecules28020608.

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A facile and efficient methodology for the generation of the C-X (X = Si, B) bond through a carbene insertion process was demonstrated using a dirhodium metal–organic cage, MOC-Rh-1, as a heterogeneous catalyst. A series of functionalized alkynes were utilized as safe carbene precursors to furnish Si-H and B-H insertion products in moderate to excellent yields. These reactions featured a high atom-economy, a broad substrate scope, and mild reaction conditions. Moreover, the as-prepared MOC-Rh-1 catalyst was recovered easily from the reaction system by simple centrifugation and reused for ten runs without a significant loss in activity, which made good use of the valuable precious metal rhodium.

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Kreisberg, Jennifer D., Philip Magnus und Shirin Shinde. „Pummerer reaction methodology for the synthesis of 5-thiophenyl substituted oxazoles“. Tetrahedron Letters 43, Nr. 41 (Oktober 2002): 7393–96. http://dx.doi.org/10.1016/s0040-4039(02)01704-5.

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36

Boddapati, S. N. Murthy, Ramana Tamminana, Ravi Kumar Gollapudi, Sharmila Nurbasha, Mohamed E. Assal, Osamah Alduhaish, Mohammed Rafiq H. Siddiqui, Hari Babu Bollikolla und Syed Farooq Adil. „Copper-Promoted One-Pot Approach: Synthesis of Benzimidazoles“. Molecules 25, Nr. 8 (14.04.2020): 1788. http://dx.doi.org/10.3390/molecules25081788.

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A facile, one-pot, and proficient method was developed for the production of various 2-arylaminobenzimidazoles. This methodology is based for the first time on a copper catalyst promoted domino C–N cross-coupling reaction for the generation of 2-arylaminobenzimidazoles. Mechanistic investigations revealed that the synthetic pathway involves a copper-based desulphurization/nucleophilic substitution and a subsequent domino intra and intermolecular C–N cross-coupling reactions. Some of the issues typically encountered during the synthesis of 2-arylaminobezimidazoles, including the use of expensive catalytic systems and the low reactivity of bromo precursors, were addressed using this newly developed copper-catalyzed method. The reaction procedure is simple, generally with excellent substrate tolerance, and provides good to high yields of the desired products.

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Buskes, Melissa J., und Maria-Jesus Blanco. „Impact of Cross-Coupling Reactions in Drug Discovery and Development“. Molecules 25, Nr. 15 (31.07.2020): 3493. http://dx.doi.org/10.3390/molecules25153493.

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Cross-coupling reactions have played a critical role enabling the rapid expansion of structure–activity relationships (SAR) during the drug discovery phase to identify a clinical candidate and facilitate subsequent drug development processes. The reliability and flexibility of this methodology have attracted great interest in the pharmaceutical industry, becoming one of the most used approaches from Lead Generation to Lead Optimization. In this mini-review, we present an overview of cross-coupling reaction applications to medicinal chemistry efforts, in particular the Suzuki–Miyaura and Buchwald–Hartwig cross-coupling reactions as a remarkable resource for the generation of carbon–carbon and carbon–heteroatom bonds. To further appreciate the impact of this methodology, the authors discuss some recent examples of clinical candidates that utilize key cross-coupling reactions in their large-scale synthetic process. Looking into future opportunities, the authors highlight the versatility of the cross-coupling reactions towards new chemical modalities like DNA-encoded libraries (DELs), new generation of peptides and cyclopeptides, allosteric modulators, and proteolysis targeting chimera (PROTAC) approaches.

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Cordes, Martin, und Markus Kalesse. „Very Recent Advances in Vinylogous Mukaiyama Aldol Reactions and Their Applications to Synthesis“. Molecules 24, Nr. 17 (22.08.2019): 3040. http://dx.doi.org/10.3390/molecules24173040.

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It is a challenging objective in synthetic organic chemistry to create efficient access to biologically active compounds. In particular, one structural element which is frequently incorporated into the framework of complex natural products is a β-hydroxy ketone. In this context, the aldol reaction is the most important transformation to generate this structural element as it not only creates new C–C bonds but also establishes stereogenic centers. In recent years, a large variety of highly selective methodologies of aldol and aldol-type reactions have been put forward. In this regard, the vinylogous Mukaiyama aldol reaction (VMAR) became a pivotal transformation as it allows the synthesis of larger fragments while incorporating 1,5-relationships and generating two new stereocenters and one double bond simultaneously. This review summarizes and updates methodology-oriented and target-oriented research focused on the various aspects of the vinylogous Mukaiyama aldol (VMA) reaction. This manuscript comprehensively condenses the last four years of research, covering the period 2016–2019.

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Zhang, Xin Ran, Wei Guang Li und Peng Fei Ren. „Natural Organic Matter Removal by UV/ Chlorine Process: Modeling and Optimization“. Advanced Materials Research 807-809 (September 2013): 466–71. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.466.

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This study evaluated and optimized the UV/ chlorine process for natural organic matters (NOMs) removal using response surface methodology (RSM). The effects of both the primary and secondary interactions of the reaction variables, including initial chlorine concentration (X1), UV radiation time (X2) and pH value (X3), were examined. A satisfactory prediction response model (R2=0.999) was obtained, indicating the reliability of the methodology. The optimum condition obtained by CCD were 4.5 mg·L-1initial chlorine concentration, 7 min UV radiation time and pH 6.7. Under the optical condition, the maximum TOC removal was 48% and TOC concentration was only 2.6 mg·L-1. The UV/ chlorine process as a novel AOP has many advantages for drinking water treatment, in terms of less chemical consumption, shorter reaction time and simpler technology.

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40

ITO, Hisanaka, Yuji HANZAWA und Takeo TAGUCHI. „Development of New Synthetic Methodology Based on Zirconium-Mediated Carbon-Carbon Bond Forming Reaction.“ Journal of Synthetic Organic Chemistry, Japan 52, Nr. 3 (1994): 217–25. http://dx.doi.org/10.5059/yukigoseikyokaishi.52.217.

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41

Das, Subrata, Rupak Banik, Brajesh Kumar, Subhadip Roy, Noorussabah, Khursheed Amhad und Pradip K. Sukul. „A Green Approach for Organic Transformations Using Microwave Reactor“. Current Organic Synthesis 16, Nr. 5 (17.10.2019): 730–64. http://dx.doi.org/10.2174/1570179416666190412160048.

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Microwave-assisted organic transformation (MAOR) is presently gaining wide popularity in the field of organic synthesis. The conventional heating technique is gradually being removed from the laboratory and a novel microwave heating technique established to be used in both academia and industry. As compared to the classical organic methodology, the green technology tools have several advantages like dramatically reduced reaction times, improved yields, site selectivity, and the increased product purities with simplification of work-up procedures. In the current study, we have briefly described the overview of recent developments and applications of microwave irradiation in organic transformation with schematic compiling of the organic reactions, bioactive heterocyclic compounds, and so on. This review also presents a critical analysis of the various advantages of microwave irradiation in organic synthesis/transformation compared to the classical or conventional heating. So, we believe that our current study of the green microwave heating technique will be highly beneficial for the researchers from both academia and industry in their near future.

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42

Devarajan, Nainamalai, und Palaniswamy Suresh. „Copper-catalyzed oxidative coupling of arylboronic acids with aryl carboxylic acids: Cu3(BTC)2 MOF as a sustainable catalyst to access aryl esters“. Organic Chemistry Frontiers 5, Nr. 15 (2018): 2322–31. http://dx.doi.org/10.1039/c8qo00519b.

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A straightforward and sustainable methodology for the synthesis of commercially important aryl esters via a C–O cross-coupling reaction was demonstrated using the Cu₃(BTC)₂ metal–organic framework.

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Chen, Ting, Song Chen, Shaomin Fu, Song Qin und Bo Liu. „Carbon–Oxygen Homocoupling of 2-Naphthols through Electrochemical Oxidative Dearomatization“. Synlett 30, Nr. 08 (11.04.2019): 903–9. http://dx.doi.org/10.1055/s-0037-1611777.

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A homocoupling reaction of 2-naphthols with formation of a C–O bond through electrochemical oxidative dearomatization in the presence of catalytic amounts of ferrocene and a ruthenium complex was developed. Mechanistic studies revealed that the reaction might proceed through coupling between two identical radical species. Moreover, a gram-scale experiment was performed to illustrate the potential practicability of this methodology in organic synthesis.

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Kumar, Rakesh, Leonard I. Wiebe und Edward E. Knaus. „A mild and efficient methodology for the synthesis of 5-halogeno uracil nucleosides that occurs via a 5-halogeno-6-azido-5,6-dihydro intermediate“. Canadian Journal of Chemistry 72, Nr. 9 (01.09.1994): 2005–10. http://dx.doi.org/10.1139/v94-256.

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A mild and efficient methodology for the synthesis of 5-halogeno (iodo, bromo, or chloro) uracil nucleosides has been developed. 5-Halo-2′-deoxyuridines 4a–c (84–95%), 5-halouridines 7a–c (45–95%), and 5-haloarabinouridines 8a–c (65–95%) were synthesized in good to excellent yields by the reaction of 2′-deoxyuridine (2), uridine (5), and arabinouridine (6), respectively, with iodine monochloride, or N-bromo (or chloro)succinimide, and sodium azide at 25–45 °C. These C-5 halogenation reactions proceed via a 5-halo-6-azido-5,6-dihydro intermediate (3), from which HN3 is eliminated, to yield the 5-halogeno uracil nucleoside. The 5-halo-6-azido-5,6-dihydro intermediate products (10a, 10b) could be isolated from the reaction of 3′,5′-di-O-acetyl-2′-deoxyuridine (9) with iodine monochloride or N-bromosuccinimide and sodium azide at 0 °C. The isolation of 10a, 10b indicates that the C-5 halogenation reaction proceeds via a 5-halo-6-azido-5,6-dihydro intermediate.

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Romero-Ortega, Moisés, Ignacio Medina-Mercado, Ivann Zaragoza-Galicia und Horacio Olivo. „2-Trifluoromethyl-1,3-diazabutadienes as Useful Intermediates for the Construction of 2-Trifluoromethylpyrimidine Derivatives“. Synthesis 50, Nr. 20 (16.07.2018): 4133–39. http://dx.doi.org/10.1055/s-0037-1610444.

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A methodology to prepare 2-trifluoromethylpyrimidines has been developed on the basis of a cyclization reaction of 2-trifluoromethyl-1,3-diazabutadienes. These 2-trifluoromethyl-1,3-diazabutadienes were prepared by the condensation of trifluoroacetamidine and amide acetals or with chloromethaniminium salt derived from N,N-dimethylbenzamide with phosphorus oxychloride. The cycloaddition reactions of these 2-trifluoromethyl-1,3-diazabutadienes with DMAD and phenylacetyl chloride provided 2-trifluoromethylpyrimidine derivatives in regular to moderate overall yield.

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Bannwart, Linda M., Pascal S. Rieder und Marcel Mayor. „2-(3-Cyanopropyldimethylsilyl)ethyl as a Polar Sulfur Protecting Group“. Synthesis 51, Nr. 22 (03.09.2019): 4153–64. http://dx.doi.org/10.1055/s-0039-1690184.

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Organosulfur compounds are ubiquitous in synthetic chemistry, biology and materials chemistry. The reactivity of free sulfhydryls requires their masking in many synthetic strategies. To facilitate the isolation of protected thiols by chromatography, we propose 2-(3-cyanopropyldimethylsilyl)ethyl as a polar protecting group analogue of 2-(trimethylsilyl)ethyl. The masked thiophenol is obtained in two synthetically complementing ways. Either an existing thiophenol is protected, or the protected thiol group is introduced by a cross-coupling reaction. In both cases the required reagents are readily available from inexpensive starting materials. Thiol protection and thiol introduction both tolerate a large variety of functional groups and substitution patterns, and the protected thiophenols are stable toward a broad range of reaction conditions. The stability of the protected derivatives in cross-coupling reactions and the mild reaction conditions for the release of the protecting group further emphasizes the potential of the methodology.

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Pandarus, Valerica, Geneviève Gingras, François Béland, Rosaria Ciriminna und Mario Pagliaro. „Clean and fast cross-coupling of aryl halides in one-pot“. Beilstein Journal of Organic Chemistry 10 (22.04.2014): 897–901. http://dx.doi.org/10.3762/bjoc.10.87.

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Unsymmetrically coupled biaryls are synthesized in high yield starting from different aryl bromides and bis(pinacolato)diboron by carrying out the Miyaura borylation reaction followed by the Suzuki–Miyaura reaction in the same reaction pot over 1–2 mol % SiliaCat DPP-Pd. The SiliaCat DPP-Pd catalyst is air-stable and the method does not require the use of inert conditions. The use of non-toxic isopropanol or 2-butanol as reaction solvent further adds to the environmental benefits of this new green synthetic methodology.

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Liu, Geng-Xin, Xiao-Ting Jie, Ge-Jun Niu, Li-Sheng Yang, Xing-Lin Li, Jian Luo und Wen-Hao Hu. „Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines“. Beilstein Journal of Organic Chemistry 20 (27.03.2024): 661–71. http://dx.doi.org/10.3762/bjoc.20.59.

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Herein, we report a visible-light-mediated palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines, affording unsaturated γ- and ε-amino acid derivatives with diverse structures. In this methodology, the diazo compound readily transforms into a hybrid α-ester alkylpalladium radical with the release of dinitrogen. The radical intermediate selectively adds to the double bond of a 1,3-diene or allene, followed by the allylpalladium radical-polar crossover path and selective allylic substitution with the amine substrate, thereby leading to a single unsaturated γ- or ε-amino acid derivative. This approach proceeds under mild and simple reaction conditions and shows high functional group tolerance, especially in the incorporation of various bioactive molecules. The studies on scale-up reactions and diverse derivatizations highlight the practical utility of this multicomponent reaction protocol.

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Patel, Chetananda, Amit Kumar, Pooja Patil und Abha Sharma. „Efficient Synthesis of Medicinally Important Benzylidene-indolin-2-one Derivatives Catalyzed by Biodegradable Amino Sugar “Meglumine”“. Letters in Organic Chemistry 16, Nr. 7 (30.05.2019): 600–605. http://dx.doi.org/10.2174/1570178615666181030095728.

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An efficient synthesis of biologically important benzylidene-indolin-2-one derivatives using meglumine as green catalyst and ethanol:water as reaction media at 78°C has been developed. The effects of reaction conditions such as solvents, temperature, and amount of catalyst were investigated. The present methodology offers many advantages such as simple procedure, less time taking to complete the reaction, high yield of products, and clean reaction profile.

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Arigela, Rajesh K., Sudhir K. Sharma, Brijesh Kumar und Bijoy Kundu. „Microwave-assisted three-component domino reaction: Synthesis of indolodiazepinotriazoles“. Beilstein Journal of Organic Chemistry 9 (19.02.2013): 401–5. http://dx.doi.org/10.3762/bjoc.9.41.

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A microwave-assisted three-component protocol involving N-1 alkylation of 2-alkynylindoles with epichlorohydrin, ring opening of the epoxide with sodium azide, and an intramolecular Huisgen azide–internal alkyne 1,3-dipolar cycloaddition domino sequence has been described. The efficacy of the methodology has been demonstrated by treating various 2-alkynylindoles (aromatic/aliphatic) with epichlorohydrin and sodium azide furnishing annulated tetracyclic indolodiazepinotriazoles in satisfactory yields.

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