- Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1-Methylimidazolium Thiocyanate
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We propose a new concept of the triple role of protic ionic liquids with nucleophilic anions: a) a regenerable solvent, b) a Br?nsted acid inducing diverse transformations via general acid catalysis, and c) a source of a nucleophile. The efficiency of this strategy was demonstrated using thiocyanate-based protic ionic liquids for the ring-opening of donor-acceptor cyclopropanes. A wide variety of activated cyclopropanes were found to react with 1-methylimidazolium thiocyanate under mild metal-free conditions via unusual nitrogen attack of the ambident thiocyanate ion on the electrophilic center of the three-membered ring affording pyrrolidine-2-thiones bearing donor and acceptor substituents at the C(5) and C(3) atoms, respectively, in a single time-efficient step. The ability of 1-methylimidazolium thiocyanate to serve as a triplex reagent was exemplarily illustrated by (4+2)-annulation with 1-acyl-2-(2-hydroxyphenyl)cyclopropane, epoxide ring-opening and other organic transformations.
- Andreev, Ivan A.,Ratmanova, Nina K.,Augustin, André U.,Ivanova, Olga A.,Levina, Irina I.,Khrustalev, Victor N.,Werz, Daniel B.,Trushkov, Igor V.
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supporting information
p. 7927 - 7934
(2021/03/03)
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- Synthesis and antimicrobial activity of thiohydantoins obtained from L-amino acids
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Background: Thiohydantoins are an important class of heterocyclic compounds in drug discovery since they are related to a wide range of biological properties including antimicrobial activity. Objective: The objective of this study was to synthesize a series of thiohydantoins derived from L-aminoacids and to evaluated their inhibitory effect on the growth of Gram-negative and Gram-positive bacteria. Methods: All title compounds were synthetized by reaction of L-amino acids with thiourea or ammonium thiocyanate. Their antimicrobial activities were evaluated against bacterial strains by broth microdilution assays. The time-kill kinetics, the antibiofilm activity and the cytotoxicity to mammalian cells were determined for the compound that exhibited the best antimicrobial profile (1b). Results: Eleven thiohydantoins were readily obtained in good yields (52-95%). In general, thiohydantoins were more effective against Gram-positive bacteria. Compound 1b (derived from L-alanine) showed the best antibacterial activity against Staphylococcus epidermis ATCC 12228 and S. aureus BEC 9393 with MIC values of 940 and 1921 μM, respectively. The time-kill kinetics demonstrated time-dependent bactericidal effect in both strains for this derivative. Besides, 1b also exhibited antibacterial activity against biofilms of S. epidermidis ATCC 12228, leading to a 40% reduction in their metabolic activity compared to the untreated control. No cytotoxicity of 1b to mammalian cells was observed at MIC values. Conclusion: The data reported herein indicate relevant antimicrobial activity of thiohydantoins derived from L-aminoacid, mainly 1b, as potential pharmacophore to guide further chemical modification aiming at the search for new and improved antimicrobial agents.
- Bispo, Marcelle de Lima Ferreira,Garbin, Renata Perugini Biasi,Macedo, Fernando,Nakazato, Gerson,Ogatta, Sueli Fumie Yamada,Ribeiro, Jhonatan Macedo,de Carvalho, Priscila Goes Camargo,de Fátima, ?ngelo
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- Catalytic enantioselective synthesis of N,Cα,Cα-trisubstituted α-amino acid derivatives using 1H-imidazol-4(5H)-ones as key templates
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Abstract 1H-Imidazol-4(5H)-ones are introduced as novel nucleophilic α-amino acid equivalents in asymmetric synthesis. These compounds not only allow highly efficient construction of tetrasubstituted stereogenic centers, but unlike hitherto known templates, provide direct access to N-substituted (alkyl, allyl, aryl) α-amino acid derivatives. A BB method: 1H-imidazol-4(5H)-ones serve as effective and easily available α-amino acid surrogates for the catalytic and highly diastereo- and enantioselective direct construction of N-substituted quaternary α-amino acid derivatives. The reaction is catalyzed by a Br?nsted base (BB) and proceeds with different Michael acceptors. EWG=electron-withdrawing group.
- Etxabe, Julen,Izquierdo, Joseba,Landa, Aitor,Oiarbide, Mikel,Palomo, Claudio
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supporting information
p. 6883 - 6886
(2015/06/08)
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- Novel and efficient protocol for the syntheses of N-1 substituted thiohydantoin and a bicyclothiohydantoin under solvent-free conditions
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A novel approach for the synthesis of N-1 substituted thiohydantoin has been developed to give quantitative yields of the desired products. The efficient synthesis of bis-thiohydantoin derivative and bicyclothiohydantoin has extended scope and applicabili
- Kumar, Vinod,Rana, Hemlata,Sankolli, Ravish,Kaushik
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experimental part
p. 2377 - 2379
(2012/05/31)
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- A simple synthesis of 2-thiohydantoins
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2-Thiohydantoin derivatives are produced by heating a mixture of thiourea and an a-amino acid. The method described offers the advantages of simplicity, low cost, easy work-up and scalability.
- Wang, Zerong Daniel,Sheikh, Samia O.,Zhang, Yulu
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p. 739 - 750
(2007/10/03)
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- Studies in Thiohydantoin Chemistry. I. Some Aspects of the Schlack-Kumpf Reaction
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An investigation has been carried out into the Schlack-Kumpf reaction, i.e., the reaction of amino acids with a mixture of acetic anhydride, acetic acid and sodium thiocyanate (occasionally ammonium thiocyanate was used). particular emphasis was placed on
- Duggan, Brendan M.,Laslett, Robert L.,Wilshire, John F. K.
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p. 541 - 550
(2007/10/03)
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