- Iron-Catalyzed Intramolecular C—H Amidation of N-Benzoyloxyureas
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A redox-neutral Fe-catalyzed intramolecular C—H amidation of N-benzoyloxyureas is described. This methodology employs a simple iron complex in situ generated from Fe(OTf)2 and bipyridine as the catalyst and N-benzoyloxyureas as the nitrene prec
- Zhong, Dayou,Wu, Lin-Yang,Wang, Xing-Zhen,Liu, Wen-Bo
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supporting information
p. 855 - 858
(2021/02/16)
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- Process for the Preparation of Zileuton
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The invention discloses a process for the preparation of Zileuton of formula I by employing acetic acid-1-benzo[b]thiophen-2-yl-ethyl-ester of formula-III as an intermediate.
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Paragraph 0112
(2017/01/19)
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- An Experimental and Computational Approach to Understanding the Reactions of Acyl Nitroso Compounds in [4 + 2] Cycloadditions
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Catalytic aerobic oxidation of phenyl hydroxycarbamate 1 and 1-hydroxy-3-phenylurea 2 using CuCl2 and 2-ethyl-2-oxazoline in methanol gave acyl nitroso species in situ, which were trapped in nitroso-Diels-Alder (NDA) reactions with various dienes to afford the corresponding cycloadducts in high yields (90-98%). Competing ene products were also present for dienes containing both alkene π-bonds and allylic σ-bonds, and the ene yields are higher with 1 than with 2. The use of the chiral hydroxamic acid, (R)-1-hydroxy-3-(1-phenylethylurea) 3 (same conditions) gave NDA cycloadducts in high yields (97-99%) with no ene product from 2,3-dimethyl-1,3-butadiene. NDA cycloadducts were not obtained from other hydroxamic acid analogues [RCONHOH (R = PhCH2 4; Ph(CH2)2 5; Ph(CH2)3 6; Ph(CH2)4 7; Ph 8; 2-pyridyl 9; 3-pyridyl 10] with various dienes using copper-oxidation but rather were obtained using sodium periodate, resulting in variable NDA yields (13-51%) from hydroxamic acids 1-10 with cyclohexa-1,3-diene and 2,3-dimethyl-1,3-butadiene (several cycloadducts characterized by X-ray crystallography). The NDA and nitroso-ene reaction pathways of nitroso intermediates with dienes were mapped by DFT computations (B3LYP/6-31G), which showed that the acyl nitroso species are super-reactive and that activation energies in the NDA processes are lower than the isomerization barriers between some cis- and trans-butadienes.
- Chaiyaveij, Duangduan,Batsanov, Andrei S.,Fox, Mark A.,Marder, Todd B.,Whiting, Andrew
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p. 9518 - 9534
(2015/10/12)
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- Stereoselective total synthesis of the potent anti-asthmatic compound CMI-977 (LDP-977)
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A short and efficient stereoselective total synthesis of CMI-977 (LDP-977), a potent and orally active anti-asthmatic compound, was developed. The key steps involve a highly diastereoselective Mukaiyama oxidative cyclization, which provides the trans-THF (tetrahydrofuran) unit and a Seyferth-Gilbert homologation to construct the triple bond in the target molecule. The synthesis of the key chiral building block was performed using Jacobsen hydrolytic kinetic resolution.
- Dias, Luiz Carlos,Farina, Lui Strambi,Ferreira, Marco Antonio Barbosa
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p. 184 - 190
(2013/05/08)
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- IMPROVED AMINOHYDROXYLATION OF ALKENES
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The invention relates to a process for the aminohydroxylation of alkenes using N-oxycarbamate reagents, e.g. N-acyloxycarbamate, N-alkyloxycarbonyloxycarbamate and N-aralkoxycarbonyloxycarbamate reagents. The invention particularly relates to an intermolecular aminohydroxylation reaction that can be carried out in the absence of added base. The invention also relates to novel N-oxycarbamate reagents that are stable crystalline materials. The process of the invention is useful in the synthesis of compounds having a vicinal amino alcohol moiety, such as biologically active compounds.
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Page/Page column 70
(2012/01/06)
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- IMPROVED PROCESS FOR THE PREPARATION OF (±)-1-(1-BENZO[B]THIEN-2-YLETHYL)-1-HYDROXYUREA
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The present invention relates to an improved process for the preparation of (±)-1-(I -Benzo[b]thien-2-ylethyl)-1-hydroxyurea compound of formula 1.
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Page/Page column 16
(2011/04/24)
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- Chemical scaffolds with structural similarities to siderophores of nonribosomal peptide-polyketide origin as novel antimicrobials against Mycobacterium tuberculosis and Yersinia pestis
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Mycobacterium tuberculosis (Mtb) and Yersinia pestis (Yp) produce siderophores with scaffolds of nonribosomal peptide-polyketide origin. Compounds with structural similarities to these siderophores were synthesized and evaluated as antimicrobials against Mtb and Yp under iron-limiting conditions mimicking the iron scarcity these pathogens encounter in the host and under standard iron-rich conditions. Several new antimicrobials were identified, including some with increased potency in the iron-limiting condition. Our study illustrates the possibility of screening compound libraries in both iron-rich and iron-limiting conditions to identify antimicrobials that may selectively target iron scarcity-adapted bacteria and highlights the usefulness of building combinatorial libraries of compounds having scaffolds with structural similarities to siderophores to feed into antimicrobial screening programs.
- Ferreras, Julian A.,Gupta, Akash,Amin, Neal D.,Basu, Arijit,Sinha, Barij N.,Worgall, Stefan,Jayaprakash, Venkatesan,Quadri, Luis E.N.
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supporting information; scheme or table
p. 6533 - 6537
(2011/12/04)
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- Design, synthesis and anticancer activity of piperazine hydroxamates and their histone deacetylase (HDAC) inhibitory activity
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Six compounds were synthesized with piperazine in linker region and hydroxamate as Zinc Binding Group (ZBG). They were screened against three cancer cell-lines (NCIH460; HCT116; U251). Compounds 5c and 5f with GI50 value of 9.33 ± 1.3 μM and 12.03 ± 4 μM, respectively, were tested for their inhibitory potential on hHDAC8. Compound 5c had IC50 of 33.67 μM. Compounds were also screened for their anticancer activity against HL60 human promyelocytic leukemia cell line due to the presence of pharmacophoric features of RR inhibitors in them. Compound 5c had IC 50 of 0.6 μM at 48 h.
- Chetan, Bhadaliya,Bunha, Mahesh,Jagrat, Monika,Sinha, Barij Nayan,Saiko, Philipp,Graser, Geraldine,Szekeres, Thomas,Raman, Ganapathy,Rajendran, Praveen,Moorthy, Dhatchana,Basu, Arijit,Jayaprakash, Venkatesan
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supporting information; experimental part
p. 3906 - 3910
(2010/09/03)
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- Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues
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The kinetics and mechanism of the degradation reactions of substituted phenyl N-hydroxycarbamates and their N-methyl and N-phenyl analogues have been studied at pseudo-first-order reaction conditions in aqueous buffers and sodium hydroxide solutions at 20°C and 60°C and at I = 1 mol·1 -1. The dependence of log kobs on pH for phenyl N-hydroxycarbamates at pH 13 is linear with the unit slope; at pH 10-12 log kobs is pH independent. The Bronsted coefficient βlg is about -1 (pH 7-13) and -1.53 (pH > 13) indicating that the degradation reaction of phenyl N-hydroxycarbamates follows an ElcB mechanism giving the corresponding phenol/phenolate and HO-N=C=O. The latter species undergoes further decomposition to give carbonate, nitrogen and ammonia as final products. In contrast to the phenyl N-hydroxycarbamates the N-methyl derivatives at pH 7-9 undergo degradation to the corresponding phenol/phenolate, carbonate and methylamine via a concerted mechanism (βlg is about - 0.75). The only exception is 4-nitrophenyl N-hydroxy-N-methylcarbamate in which the predominant break down pathway proceeds via the Smiles rearrangement to give sodium N-methyl-(4-nitrophenoxy)carbamate. At pH > 9 the reaction of N-hydroxy-N-methylcarbamates is kinetically complex: the dependence of absorbance on time is not exponential and it proceeds as a consecutive two-step reaction. N-Hydroxy-N-phenylcarbamate under the same conditions undergoes degradation to phenol, carbonate, aniline and azoxybenzene.
- Beier, Petr,Mindl, Jaromir,Sterba, Vojeslav,Hanusek, Jiri
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p. 562 - 569
(2007/10/03)
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- Herbicidal oxadiazolidines
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Compounds of Formula (1) and processes for their preparation, their N-oxides and agriculturally suitable salts, are disclosed which are useful for controlling undesired vegetation wherein Q, X1, X2, X3, R1, Rsu
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- Synthesis, biological evaluation, and quantitative structure -activity relationship analysis of new Schiff bases of hydroxysemicarbazide as potential antitumor agents
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Thirty Schiff bases of hydroxysemicarbazide (Ar-CH=NNHCONHOH) have been synthesized and tested against L1210 murine leukemia cells. The IC50 values were found to be in a range from 2.7 × 10-6 to 9.4 × 10-4 M. A total of 17
- Ren, Shijun,Wang, Rubin,Komatsu, Kenichi,Bonaz-Krause, Patricia,Zyrianov, Yegor,McKenna, Charles E.,Csipke, Csaba,Tokes, Zoltan A.,Lien, Eric J.
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p. 410 - 419
(2007/10/03)
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- Asymmetric Diels-Alder Cycloadditions with Chiral Carbamoyl Dienophiles
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Chiral acylnitroso dienophiles 14, which were obtained from L-proline and from D-mandelic acid, reacted with cyclohexa-1,3-diene to give the expected diastereoisomers 15 and 16 (Scheme 2 and Table 1).The d.e. values for these Diels-Alder reactions were moderate; they are related to the molecular stiffness of the dienophiles.The absolute configuration of the major cycloadducts was interpreted in terms of HOMO/LUMO interactions, the approach being 'endo' and the acylnitroso dienophiles reacting from their s-cis-conformation.
- Defoin, Albert,Brouillard-Poichet, Agnes,Streith, Jacques
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p. 109 - 123
(2007/10/02)
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