53933-47-4Relevant academic research and scientific papers
Analogues of the Herbicide, N-Hydroxy- N-isopropyloxamate, Inhibit Mycobacterium tuberculosis Ketol-Acid Reductoisomerase and Their Prodrugs Are Promising Anti-TB Drug Leads
Kandale, Ajit,Patel, Khushboo,Hussein, Waleed M.,Wun, Shun Jie,Zheng, Shan,Tan, Lendl,West, Nicholas P.,Schenk, Gerhard,Guddat, Luke W.,McGeary, Ross P.
, p. 1670 - 1684 (2021/02/27)
New drugs to treat tuberculosis (TB) are urgently needed to combat the increase in resistance observed among the current first-line and second-line treatments. Here, we propose ketol-acid reductoisomerase (KARI) as a target for anti-TB drug discovery. Twenty-two analogues of IpOHA, an inhibitor of plant KARI, were evaluated as antimycobacterial agents. The strongest inhibitor of Mycobacterium tuberculosis (Mt) KARI has a Ki value of 19.7 nM, fivefold more potent than IpOHA (Ki = 97.7 nM). This and four other potent analogues are slow- and tight-binding inhibitors of MtKARI. Three compounds were cocrystallized with Staphylococcus aureus KARI and yielded crystals that diffracted to 1.6-2.0 ? resolution. Prodrugs of these compounds possess antimycobacterial activity against H37Rv, a virulent strain of human TB, with the most active compound having an MIC90 of 2.32 ± 0.04 μM. This compound demonstrates a very favorable selectivity window and represents a highly promising lead as an anti-TB agent.
Phyllosilicate-derived Nickel-cobalt Bimetallic Nanoparticles for the Catalytic Hydrogenation of Imines, Oximes and N-heteroarenes
Ciotonea, Carmen,Hammi, Nisrine,Dhainaut, Jérémy,Marinova, Maya,Ungureanu, Adrian,El Kadib, Abdelkrim,Michon, Christophe,Royer, Sébastien
, p. 4652 - 4663 (2020/08/19)
The development of cost-effective, noble metal-free catalytic systems for the hydrogenation of unsaturated aliphatic, aromatic, and heterocyclic compounds is fundamental for future valorization of general feedstock. With this aim, we report here the preparation of highly dispersed bimetallic Ni/Co nanoparticles (NPs), by a one-pot deposition-precipitation of Ni and Co phases onto mesoporous SBA-15 silica. By adjusting the chemical composition in the starting mixture, three supported catalysts with different Ni to Co weight ratios were obtained, which were further subjected to treatments under reducing conditions at high temperatures. Characterization of the resulting solids evidenced a homogenous distribution of Ni and Co elements forming the NPs, the best results being obtained for Ni/Co-2 : 2 samples, for which 50 wt.percent Ni–50 wt.percent Co NPs are found located on the surface of the residual phyllosilicate. Ni/Co-2 : 2, presenting the best performances for the hydrogenation of 2-methyl-quinoline, was further evaluated in the catalytic hydrogenation of selected imines, oximes and N-heteroarenes. Due to the high dispersion of bimetallic Ni?Co NPs, excellent properties (activity and selectivity) in the conversion of the selected substrates are reported.
Ultrasonic promoted synthesis of Ag nanoparticle decorated thiourea-functionalized magnetic hydroxyapatite: A robust inorganic-organic hybrid nanocatalyst for oxidation and reduction reactions
Bahadorikhalili, Saeed,Arshadi, Hosein,Afrouzandeh, Zahra,Ma'mani, Leila
, p. 8840 - 8848 (2020/06/08)
In this research, ultrasonic synthesis is applied for the fabrication of a novel catalyst, based on immobilization of silver nanoparticles (AgNPs) on thiourea functionalized magnetic hydroxyapatite. A recoverable Ag nano-catalyst is constructed by decoration of AgNPs on the surface of thiourea modified magnetic hydroxyapatite. Magnetic hydroxyapatite is used as an organic-inorganic hybrid support for the catalyst. The organic-inorganic hybrid support is prepared by co-precipitation, followed by its surface modification through covalent functionalization of 1-(3,5-bis(trifluoromethyl)phenyl)-3-propyl)thiourea. The fabricated catalyst has been characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) analysis. The nanoparticles are mostly tubular in shape and their particle sizes are smaller than 100 nm. This nanocatalyst shows efficient and robust catalytic activity in different reactions, including selective reduction of 4-nitrophenol (4NP) and oxidation of primary amines by applying NaBH4and urea hydrogen peroxide (UHP) as reagents, respectively. The catalyst shows good reusability in 10 sequential reaction runs.
B(C6F5)3-catalyzed hydrogenation of oxime ethers without cleavage of the N-O bond
Mohr, Jens,Oestreich, Martin
, p. 13278 - 13281 (2015/01/16)
The hydrogenation of oximes and oxime ethers is usually hampered by N-O bond cleavage, hence affording amines rather than hydroxylamines. The boron Lewis acid B(C6F5)3 is found to catalyze the chemoselective hydrogenation
Asymmetric α-oxyacylation of cyclic ketones
Smithen, Deborah A.,Mathews, Christopher J.,Tomkinson, Nicholas C.O.
supporting information; experimental part, p. 3756 - 3762 (2012/06/01)
Reaction of cyclic ketones with chiral N-alkyl-O-acyl hydroxylamines leads to the corresponding α-oxyacylated carbonyl compound in up to 89% ee. The levels of asymmetric induction were influenced by solvent polarity, acid strength and, to a lesser extent,
The mechanism of the α-ketoacid-hydroxylamine amide-forming ligation
Pusterla, Ivano,Bode, Jeffrey W.
supporting information; experimental part, p. 513 - 516 (2012/03/22)
Three-ring circus! Surprisingly complex molecular acrobatics are observed in the mechanism of the α-ketoacid-hydroxylamine amide-forming ligation reaction. Although this remarkable reaction can already be used for the chemoselective union of large, unprotected peptide fragments the elucidated mechanism provides important clues to extending its application to larger and more complex biological targets. Copyright
Minimisation of E-Factor in the synthesis of N-hydroxylamines: The role of silver(i)-based coordination polymers
Sheykhan, Mehdi,Rashidi Ranjbar, Zohreh,Morsali, Ali,Heydari, Akbar
experimental part, p. 1971 - 1978 (2012/08/14)
Among four different 2-D polymeric silver(i)-bpfb assemblies synthesized, [Ag(μ-bpfb)(N3)]n (4c) having an azide anion was shown to be the best catalyst for the partial oxidation of primary amines to N-monoalkylhydroxylamines with ur
Conjugate addition of lithium N-tert-butyldimethylsilyloxy-N-(α-methylbenzyl)amide: asymmetric synthesis of β2,2,3-trisubstituted amino acids
Bentley, Scott A.,Davies, Stephen G.,Lee, James A.,Roberts, Paul M.,Russell, Angela J.,Thomson, James E.,Toms, Steven M.
scheme or table, p. 4604 - 4620 (2010/07/05)
Conjugate addition of the homochiral ammonia equivalent lithium N-tert-butyldimethylsilyloxy-N-(α-methylbenzyl)amide to a range of α,β-unsaturated esters gives the corresponding β-amino esters in moderate to good levels of diastereoselectivity. O-Desilylation and cyclisation furnishes homochiral isoxazolidin-5-ones in >99:1 dr after purification. Sequential alkylation of these templates proceeds to give the corresponding 3,4-anti-disubstituted and 3,4,4-trisubstituted derivatives as single diastereoisomers after purification. The first alkylation occurs with high levels of diastereoselectivity on the face of the enolate anti to the C(3)-substituent, whereas the facial selectivity of the second alkylation is governed by a chiral relay effect, which depends upon the relative steric bulk of both the C(3)- and C(4)-substituents. Subsequent hydrogenolysis promotes cleavage of both the N-α-methylbenzyl group and the N-O bond within the isoxazolidin-5-one ring in one pot to give the corresponding β2,2,3-trisubstituted amino acids directly.
On the origins of diastereoselectivity in the alkylation of enolates derived from N-1-(1′-Naphthyl)ethyl-O-tert-butylhydroxamates: Chiral Weinreb amide equivalents
Davies, Stephen G.,Goodwin, Christopher J.,Hepworth, David,Roberts, Paul M.,Thomson, James E.
supporting information; experimental part, p. 1214 - 1227 (2010/04/26)
(Chemical Equation Presented) The stereochemical outcome observed upon alkylation of enolates derived from N-1-(1′-naphthyl)ethyl-O-tert- butylhydroxamates (chiral Weinreb amide equivalents) may be rationalized by a chiral relay mechanism. Deprotonation withKHMDS leads to a nonchelated (Z)-enolate inwhich the oxygen atoms adopt an anti-periplanar conformation. The configuration of the N-1-(1′-naphthyl)ethyl group dictates the conformation of the O-tert-butyl group and the configuration adopted by the adjacent pyramidal nitrogen atom. Highly diastereoselective enolate alkylation then proceeds anti to both the bulky tert-butyl group (sterically driven) and the N-lone pair (stereoelectronically driven).
Asymmetric synthesis of N-substituted N-hydroxyureas
Laczkowski, Krzysztof Z.,Pakulski, Marcin M.,Krzeminski, Marek P.,Jaisankar, Parasuraman,Zaidlewicz, Marek
, p. 788 - 795 (2008/09/20)
Asymmetric synthesis of (S)-N-(1-arylethyl)-N-hydroxyureas, (S)-N-(6-methoxy)- and (S)-N-(6-benzyloxy-2,3-dihydrobenzofuran-3-yl)-N-hydroxyurea- lipoxygenase inhibitor, is described. Three approaches to the formation of the N-hydroxyurea moiety at the stereogenic center have been used. The first one, via the reaction of (R)-6-benzyloxy-2,3-dihydrobenzofuran-3-ol with N,O-bis(phenoxycarbonyl)hydroxylamine under Mitsunobu conditions, leads to a partially racemized product. Alternatively, the enantioselective reduction of oximes O-benzyl ethers of acetophenone, 4-methoxy- and 4-benzyloxyacetophenone, 6-methoxy- and 6-benzyloxy-2,3-dihydrobenzofuran-3-one with borane/oxazaborolidines can be controlled to produce either the corresponding hydroxylamine O-benzyl ethers or primary amines which have been transformed into N-substituted N-hydroxyureas in 57% to 99% ee.
