- Cu(OAc)2-porphyrins as an efficient catalytic system for base-free, nature mimicking Chan–Lam coupling in water
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The use of porphyrins as ligands in organic synthesis reveals the natural process, because these are the constituent motifs of catalysts in many bio-organic reactions. This article presents the synthesis of two N-pincer tetradentate porphyrins; tetrasodium meso-tetra(p-sulfonatophenyl)phorphyrin (H2TSTpSPP) and meso-tetra(m-carboxyphenyl)porphyrin (H2TmCPP), and study on their aptness for Cu-catalyzed C–N coupling reactions of arylboronic acids and amines (Chan–Lam coupling reaction) in water under external base free conditions. The porphyrins and Chan–Lam coupling products were well characterized by their spectral analysis. The high product yields, application of nature-inspired conditions, large extent of substrates, ease of making and handling the ligands, avoidance of base, and use of water as reaction media are the attractive attributes of this finding.
- Venkateswarlu, Katta,Rao, Kanusu Umamaheswara
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- Recycling method of 1-phenyl-5-hydroxytetrazole
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The invention discloses a recycling method of 1-phenyl-5-hydroxytetrazole, and belongs to the technical field of medicinal chemistry. The preparation method comprises the following steps: a byproduct1-phenyl-5-hydroxytetrazole generated in preparation process of a rosuvastatin calcium intermediate is converted into 1-phenyl-5-mercaptotetrazole; and meanwhile, the 1-phenyl-5-mercaptotetrazole is further used for preparing a rosuvastatin calcium intermediate or rosuvastatin calcium. According to the method disclosed by the invention, reasonable recycling of the byproduct 1-phenyl-5-hydroxytetrazole is realized, the raw materials are fully utilized, the production cost of rosuvastatin calcium and the intermediate thereof is reduced, and the emission of three wastes is reduced.
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Paragraph 0051-0053; 0058-0059
(2020/01/12)
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- Electronic properties of 1-methyl-4-phenyl-1H-tetrazole-5(4H)-thiones: An experimental and theoretical study
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The syntheses of 1-(4-methoxyphenyl)-4-methyl-1H-tetrazol-5(4H)-thione 1a, 1-methyl-4-phenyl-1H-tetrazole-5(4H)-thione 1b, 1-(4-chlorophenyl)-4-methyl-1H-tetrazol-5(4H)-thione 1c, 1-methyl-4-(4-nitrophenyl)-1H-tetrazol-5(4H)-thione 1d were carried out and their electronic absorption spectra were obtained in cyclohexane, THF, and acetonitrile. The UV spectra of 1a-d showed a modest dependence on the polarity of the solvent. The change of substituent on the tetrazolethione ring from a strongly electron donating group (p-C6H4OMe, 1a), to a moderately electron donating (C6H5, 1b) to a weakly electron withdrawing group (p-C6H4Cl, 1c) also produced minimal effect on the electronic properties of 1a-c. However, the presence of a strongly electron withdrawing group (p-C6H4NO2, 1d) on the heterocyclic ring produced a marked change in the UV spectrum. Time-dependent density functional calculations revealed that all the bands result from π → π* excitations with some degree of intramolecular charge transfer (ICT) within the molecules. Our studies further showed that as the acceptor strength is increased in the order: 1a (p-C6H4OMe) 6H5) 6H4Cl) 6H4NO2), the ICT also increases. In accordance with the experimental observations, the calculated transitions also showed modest dependence on the polarity of the solvent.
- Rayat, Sundeep,Chhabra, Radhika,Alawode, Olajide,Gundugola, Aditya S.
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experimental part
p. 38 - 45
(2010/02/16)
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- Improved preparation of 5-chloro-1-phenyl-1H-tetrazole and other 5- chlorotetrazoles
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Reaction of aryldichloroisocyanides 1a-e with sodium azide and a phase transfer agent has provided 5-chloro-1-aryl-1H-tetrazoles 2a-e in good yield. In particular, the widely-used intermediate, 5-chloro-1-phenyl-1H-tetrazole 2a, can be produced conveniently and safely in yields approaching 100%.
- Alves, Jose A.C.,Johnstone, Robert A.W.
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p. 2645 - 2650
(2007/10/03)
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