- Synthesis and SAR study of simple aryl oximes and nitrofuranyl derivatives with potent activity against Mycobacterium tuberculosis
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Background: Oximes and nitrofuranyl derivatives are particularly important compounds in medicinal chemistry. Thus, many researchers have been reported to possess antibacterial, antiparasitic, insecticidal and fungicidal activities. Methods: In this work, we report the synthesis and the biological activity against Mycobacterium tuberculosis H37RV of a series of fifty aryl oximes, ArCH=N-OH, I, and eight nitrofuranyl compounds, 2-nitrofuranyl-X, II. Results: Among the oximes, I: Ar = 2-OH-4-OH, 42, and I: Ar = 5-nitrofuranyl, 46, possessed the best activity at 3.74 and 32.0 μM, respectively. Also, 46, the nitrofuran compounds, II; X = MeO, 55, and II: X = NHCH2Ph, 58, (14.6 and 12.6 μM, respectively), exhibited excellent biological activities and were non-cytotoxic. Conclusion: The compound 55 showed a selectivity index of 9.85. Further antibacterial tests were performed with compound 55 which was inactive against Enterococcus faecalis, Klebisiella pneumonae, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhymurium and Shigel-la flexneri. This study adds important information to the rational design of new lead anti-TB drugs. Structure-activity Relationship (SAR) is reported.
- Calixto, Stephane Lima,Carvalho, Guilherme da Silva Louren?o,Coimbra, Elaine Soares,Granato, Juliana da Trindade,Louren?o, Maria Cristina da Silva,Wardell, James,da Costa, Cristiane Fran?a,de Souza, Marcus Vinicius Nora
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- A New Process for the Total Synthesis of Sparstolonin B
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A novel and simple route was developed that gives sparstolonin B in high yields from affordable commercial compounds. A Diels-Alder strategy was used for the facile construction of the multisubstituted diphenyl ether. The xanthenone segment was obtained by cyclization in an intramolecular Friedel-Crafts reaction, followed by selective reduction of a ketone group and a transformation from a hydroxy group into a cyano group. The final part of the lactone was directly derived by the reduction of the cyano group with Raney nickel.
- Tang, Xiaohang,Tong, Le,Yao, Mengyi,Liang, Qiaoli,Wang, Xiaolong,Yu, Haitao
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p. 1187 - 1190
(2017/06/13)
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- Synthesis method of natural product sparstolonin B (SsnB) and key intermediates thereof
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The invention provides a synthesis method of a natural product sparstolonin B (SsnB) and three key intermediates thereof. The method for synthesizing the natural product SsnB has the advantages of simple synthesis route, convenient after-treatment and higher yield. All the reagents are cheap and accessible, the reaction temperature is low, and the reaction time is short. The method can well relieve the demands for SsnB, and can overcome the defects in the prior art.
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Paragraph 0039; 0040; 0041
(2016/10/31)
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- Rate-product correlations for the solvolysis of 5-nitro-2-furoyl chloride
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The solvolysis rate constants of 5-nitro-2-furoyl chloride (5-NO 2(C4H2O)-2-COCl, 1) in 27 different solvents are well correlated with the extended Grunwald-Winstein equation, using the NT solvent nucleophilicity scale and YCl solvent ionizing scale, with sensitivity values of 1.20 ± 0.05 and 0.37 ± 0.02 for l and m, respectively. The activation enthalpies (ΔH≠) were 5.63 to 13.0 kcal·mol-1 and the activation entropies (ΔS ≠) were .25.9 to .43.4 cal·mol-1·K -1, which is consistent with the proposed bimolecular reaction mechanism. The solvent kinetic isotope effect (SKIE, kMeOH/kMeOD) of 2.65 was also in accord with the SN2 mechanism and was possibly assisted using a general-base catalysis. The product selectivity (S) for solvolysis of 1 in alcohol/water mixtures was 1.2 to 11, which is also consistent with the proposed bimolecular reaction mechanism.
- Choi, Hojune,Koh, Han Joong,Ali, Dildar,Yang, Kiyull,Koo, In Sun
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p. 3293 - 3297
(2013/01/15)
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- Continuous flow oxidation of alcohols and aldehydes utilizing bleach and catalytic tetrabutylammonium bromide
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We report a method for the oxidation of a range of alcohols and aldehydes utilizing a simple flow system of alcohols in EtOAc with a stream of 12.5% NaOCl and catalytic Bu4NBr. Secondary alcohols are oxidized to ketones, aldehydes are oxidized directly to methyl esters in the presence of methanol, and benzylic alcohols are oxidized to either benzaldehydes or methyl esters, depending on the conditions used. The reaction conditions are mild and generally provide complete conversion in 5-30 min.
- Leduc, Andrew B.,Jamison, Timothy F.
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supporting information; experimental part
p. 1082 - 1089
(2012/08/27)
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- Hydroperoxide oxidation of different organic compounds catalyzed by silica-supported selenenamide
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The recoverable heterogeneous silica-supported catalyst selenenamide 2 was prepared by the coupling of 3-aminopropylsilicate (4) with 2-chloroselenobenzoyl chloride (6). Its catalytic activity was demonstrated in tert-butyl hydroperoxide oxidation of aldehydes 8 to carboxylic acids 9 and benzylamines 17 to nitriles 18. Moreover, it was employed for hydrogen peroxide oxidation of azomethine compounds such as tosylhydrazones 10, oximes 13 and N,N-dimethylhydrazones 16 to parent ketones 12, arenecarboxylic acids 11 and 15, their methyl esters 14 and nitriles 18 depending on the substrate used and the reaction conditions. The catalyst was simply recovered by filtration and could be reused.
- Giurg,Brzaszcz,Mlochowski
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p. 417 - 428
(2007/10/03)
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- Electrophilic tetraalkylammonium nitrate nitration. II. Improved anhydrous aromatic and heteroaromatic mononitration with tetramethylammonium nitrate and triflic anhydride, including selected microwave examples
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A new one-pot nitration employing tetramethylammonium nitrate and trifluoromethanesulfonic anhydride in dichloromethane to provide a ready source of the nitronium triflate nitrating agent is presented. Rapid and selective nitration with a variety of aromatic and heteroaromatic substrates is achieved resulting in the synthesis of several novel organic compounds. A distinct advantage is the removal of undesired byproducts by aqueous workup. This very mild nitration permits large-scale syntheses and gives high isolated product yields that often require no further purification. This tetramethylammonium nitrate-based nitration also has been applied to microwave-assisted conditions, and the results with several compounds are outlined.
- Shackelford, Scott A.,Anderson, Mark B.,Christie, Lance C.,Goetzen, Thomas,Guzman, Mark C.,Hananel, Martha A.,Kornreich, Wayne D.,Li, Haitao,Pathak, Ved P.,Rabinovich, Alex K.,Rajapakse, Ranjan J.,Truesdale, Larry K.,Tsank, Stella M.,Vazir, Haresh N.
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p. 267 - 275
(2007/10/03)
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- Antitrypanosomal activities and cytotoxicity of 5-nitro-2-furancarbohydrazides
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A series of 5-nitro-2-furancarbohydrazides were synthesized. In vitro antitrypanosomal activities of these compounds were determined against the closely related protozoa Trypanosoma cruzi Trypanosoma brucei and discussed in relation to potential targets.
- Millet, Régis,Maes, Louis,Landry, Valérie,Sergheraert, Christian,Davioud-Charvet, Elisabeth
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p. 3601 - 3604
(2007/10/03)
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- Diels-Alder Reaction of 2-Amino-Substituted Furans as a Method for Preparing Substituted Anilines
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5-Amino-2-furancarboxylic acid methyl ester undergoes a facile Diels-Alder cycloaddition with a variety of dienophiles to afford ring-opened cycloadducts that are readily dehydrated using BF3-OEt2 to give polysubstituted anilines. In each case, the cycloaddition proceeds with high regioselectivity, with the electron-withdrawing group being located ortho to the amino group. The most favorable FMO interaction is between the HOMO of the furanamine and the LUMO of the dienophile. The atomic coefficient at the ester carbon of the furan is larger than that at the amino center, and this nicely accommodates the observed regioselectivity. The [4 + 2]-cycloaddition of N-(5-nitrofuranyl)morpholine with methyl vinyl ketone affords a mixture of three phenols. One of the phenols is derived from a Diels - Alder reaction followed by nitro group ejection and subsequent aromatization. The remaining two phenols are the result of cleavage of the initially formed oxabicyclic intermediate with concomitant migration of the nitro group. The mild reaction conditions with which furan-2-carbamic acid tert-butyl ester undergoes Diels - Alder cycloaddition with N-phenylmaleimide allow for the ready isolation of the initial oxybridged cycloadduct.
- Padwa, Albert,Dimitroff, Martin,Waterson, Alex G.,Wu, Tianhua
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p. 4088 - 4096
(2007/10/03)
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- A practical synthesis of 5-(chloromethyl)furo[2,3-b]pyridine, a key intermediate for the HIV protease inhibitor, L-754,394
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A practical synthesis of 5-(chloromethyl)furo[2,3-b]pyridine (10), the side chain used to incorporate a key pharmacophore of the HIV protease inhibitor, L-754,394, is described. The synthesis was accomplished in ten steps and in 15% overall yield from com
- Bhupathy,Conlon,Wells,Nelson,Reider,Rossen,Sager,Volante,Dorsey,Hoffman Jr.,Joseph,McDaniel
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p. 1283 - 1287
(2007/10/03)
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- Facile Conversions of Carboxylic Acids into Amides, Esters, and Thioesters Using 1,1'-Oxalyldiimidazole and 1,1'-Oxalyldi(1,2,4-triazole)
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Aliphatic, aromatic, and heteroaromatic carboxylic acids react with 1,1'-oxalyldiimidazole (1) or 1,1'-oxalyldi(1,2,4-triazole) (2) in acetonitrile for 40 min at 40 degC to give the corresponding 1-acylazole intermediates (11), which promptly undergo aminolysis and alcoholysis to form amides (13) including dipeptides (14), esters (16), and thioesters (19).These findings show that both 1 and 2 can be utilized as condensing reagents for the synthesis of carboxylic acid derivatives.Keywords --- 1,1'-oxalyldiimidazole; 1,1'-oxalyldi(1,2,4-triazole); 1,1'-carbonyldiimidazole; 1-acylazole; condensing reagent; amidation; esterification; dipeptide; aminolysis; alcoholysis
- Kitagawa, Tokujiro,Kuroda, Hiroko,Sasaki, Hideaki,Kawasaki, Koichi
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p. 4294 - 4301
(2007/10/02)
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- Nitronium Acetate Adducts of Furan Derivatives
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An improved procedure for the isolation of the main addition products of the reaction between nitronium acetate and furfural diacetate or methyl 2-furoate is described.The kinetics of the deacetylation of the diastereomeric 1,4-adducts in buffer solutions revealed a substantial primary hydrogen isotope effect.Mild acid-induced alcoholysis transformed the adducts into 2,5-dialkoxy-2,5-dihydrofurans.The reaction chemistry of the furan adducts is compared with the solvolytic pathways reported for ipso nitronium acetate adducts formed from alkylbenzenes.
- Balina, Gisela,Kesler, Patricia,Petre, Janet,Pham, Dung,Vollmar, Arnulf
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p. 3811 - 3818
(2007/10/02)
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- Nitration of Methyl 2-Furoate with Acetyl Nitrate. On the Configurations of Six Isolated Intermediary Adducts
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Reaction of methyl 2-furoate with acetyl nitrate afforded the isolation of six adducts whose stereochemistry was determined: (E)- and (Z)-2-carbomethoxy-2-acetoxy-5-nitro-2,5-dihydrofuran, (E)- and (Z)-2-carbomethoxy-4-acetoxy-5-nitro-4,5-dihydrofuran, an
- Kolb, Vera M.,Darling, Stephen D.,Koster, David F.,Meyers, Cal Y.
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p. 1636 - 1639
(2007/10/02)
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