cas 456-07-5, 4-fluoro-N-hydroxybenzamide | Articles data

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Cu(II)-Catalyzed C-H Amidation/Cyclization of Azomethine Imines with Dioxazolones via Acyl Nitrenes: A Direct Access to Diverse 1,2,4-Triazole Derivatives
We report a Cu(II)-catalyzed C-H amidation/cyclization of azomethine imines with dioxazolones as acyl nitrene transfer reagents under additive-and ligand-free conditions. An array of 1,2,4-triazolo[1,5-a]pyridine derivatives were afforded in moderate to good yields with excellent functional group tolerance. In addition, scale-up reaction and photoluminescence properties were discussed.
Liu, Xiang,Li, Wen,Jiang, Wenxuan,Lu, Hao,Liu, Jiali,Lin, Yijun,Cao, Hua
supporting information
p. 613 - 618
(2022/01/20)

Palladium-Catalyzed 5-exo-dig Cyclization Cascade, Sequential Amination/Etherification for Stereoselective Construction of 3-Methyleneindolinones
An cascade intramolecular 5-exo-dig cyclization of N-(2-iodophenyl)propiolamides and sequential amination/etherification (with N-hydroxybenzamides, phenyl hydroxycarbamate) protocol for the synthesis of amino- and phenoxy-substituted 3-methyleneindolinones using unexpensive Pd(PPh3)4 as catalyst has been developed. The protocol enables the assembly of structurally important oxindole cores featuring moderate functional group tolerance (particularly the halo group), affording a broad spectrum of products with diverse substituents in good to excellent yields. (Figure presented.).
Zuo, Youpeng,He, Xinwei,Tang, Qiang,Hu, Wangcheng,Zhou, Tongtong,Hu, Wenbo,Shang, Yongjia
p. 2117 - 2123
(2020/12/22)

Thioether-Directed NiH-Catalyzed Remote γ-C(sp3)-H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones
A NiH-catalyzed thioether-directed cyclometalation strategy is developed to enable remote methylene C-H bond amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)-H bonds to afford the amide products in up to 90% yield (>40 examples) with remarkable regioselectivity (up to 24:1 rr).
Chen, Qishu,Du, Bingnan,Ouyang, Yuxin,Yu, Wing-Yiu
supporting information
p. 14962 - 14968
(2021/09/29)

Direct synthesis of benzoxazinones via Cp*Co(III)-catalyzed C–H activation and annulation of sulfoxonium ylides with dioxazolones
A highly novel and direct synthesis of benzoxazinones was developed via Cp*Co(III)-catalyzed C–H activation and [3 + 3] annulation between sulfoxonium ylides and dioxazolones. The reaction is conducted under base-free conditions and tolerates various functional groups. Starting from diverse readily available sulfoxonium ylides and dioxazolones, a variety of benzoxazinones could be synthesized in one step in 32%-75% yields.
Yu, Yongqi,Xia, Zhen,Wu, Qianlong,Liu, Da,Yu, Lin,Xiao, Yuanjiu,Tan, Ze,Deng, Wei,Zhu, Gangguo
supporting information
p. 1263 - 1266
(2020/10/08)

Synthesis of sulfimides and N-Allyl-N-(thio)amides by Ru(II)catalyzed nitrene transfer reactions of N-acyloxyamides
The N-acyloxyamides were employed as effective N-acyl nitrene precursors in reactions with thioethers under the catalysis of a commercially available Ru(II) complex, from which a variety of sulfimides were synthesized efficiently and mildly. If an allyl group is contained in the thioether precursor, the [2,3]-sigmatropic rearrangement of the sulfimide occurs simultaneously and the N-allyl-N-(thio)amides were obtained as the final products. Preliminary mechanistic studies indicated that the Ru-nitrenoid species should be a key intermediate in the transformation.
Zhang, Xinyu,Lin, Bo,Chen, Jianhui,Chen, Jiajia,Luo, Yanshu,Xia, Yuanzhi
supporting information
p. 819 - 825
(2021/02/01)

Palladium-catalyzed cascade decarboxylative amination/6- endo-dig benzannulation of o-alkynylarylketones with n-hydroxyamides to access diverse 1-naphthylamine derivatives
An efficient and practical one-pot strategy to produce highly substituted 1-naphthylamines via sequential palladium-catalyzed decarboxylative amination/intramolecular 6-endo-dig benzannulation reactions has been described. In this reaction, a broad range of electron-rich, electron-neutral, and electron-deficient o-alkynylarylketones react well with N-hydroxyl aryl/alkylamides to give a diversity of 1-naphthylamines in good to excellent yields under mild reaction conditions. The gram-scale synthesis, with benefits such as undiminished product yield and easy transformation, illustrated the practicality of this method.
Zuo, Youpeng,He, Xinwei,Tang, Qiang,Hu, Wangcheng,Zhou, Tongtong,Shang, Yongjia
p. 3890 - 3894
(2020/05/18)

Divergent Synthesis of Tunable Cyclopentadienyl Ligands and Their Application in Rh-Catalyzed Enantioselective Synthesis of Isoindolinone
A series of rhodium complexes bearing sterically and electronically tunable cyclopentadienyl ligands, prepared by utilizing Co2(CO)8-mediated [2+2+1] cyclization as a key step, were synthesized. In the presence of 2.5 mol% of CpmRh4, unprecedented enantioselective [4+1] annulation reaction of benzamides and alkenes was achieved with a broad substrate scope under mild reaction conditions, providing a variety of isoindolinones with excellent regio-and enantioselectivity (up to 94% yield, 97:3 er). Preliminary mechanistic studies suggest that the reaction involves an oxidative Heck reaction and an intramolecular enantioselective alkene hydroamination reaction.
Cui, Wen-Jun,Wu, Zhi-Jie,Gu, Qing,You, Shu-Li
p. 7379 - 7385
(2020/08/19)

RhIII-Catalyzed C?H Activation of Aryl Hydroxamates for the Synthesis of Isoindolinones
RhIII-catalyzed C?H functionalization reaction yielding isoindolinones from aryl hydroxamates and ortho-substituted styrenes is reported. The reaction proceeds smoothly under mild conditions at room temperature, and tolerates a range of functional groups. Experimental and computational investigations support that the high regioselectivity observed for these substrates results from the presence of an ortho-substituent embedded in the styrene. The resulting isoindolinones are valuable building blocks for the synthesis of bioactive compounds. They provide easy access to the natural-product-like compounds, isoindolobenzazepines, in a one-pot two-step reaction. Selected isoindolinones inhibited Hedgehog (Hh)-dependent differentiation of multipotent murine mesenchymal progenitor stem cells into osteoblasts.
Shaaban, Saad,Davies, Caitlin,Merten, Christian,Flegel, Jana,Otte, Felix,Strohmann, Carsten,Waldmann, Herbert
supporting information
p. 10729 - 10734
(2020/07/25)

Rhodium(III)-catalyzed C4-amidation of indole-oximes with dioxazolones: Via C-H activation
A novel method for the Rh(III)-catalyzed oxime-directed C-H amidation of indoles with dioxazolones has been developed. This strategy provides an exclusive site selectivity and the directing group can be easily removed. This transformation features a wide substrate scope, good functional group tolerance and excellent yields, and may serve as a significant tool to construct structurally diverse indole derivatives for the screening of potential pharmaceuticals in the future. This journal is
Deng, Ke-Zuan,Fu, Xiao-Pan,Ji, Ya-Fei,Tang, Shi-Biao,Wu, Gao-Rong,Xia, Cheng-Cai,Yang, Jin-Yue,Zhang, Li-Li
supporting information
p. 7922 - 7931
(2020/11/02)

Dioxazolones as masked ester surrogates in the Pd(ii)-catalyzed direct C-H arylation of 6,5-fused heterocycles
A simple and effective Pd(ii)-catalyzed regioselective C(2)-H arylation of 6,5-fused heterocycles with dioxazolones as a masked ester surrogate under mild conditions is reported. The significance of the arylation is highlighted by the new reactivity demonstrated in dioxazolones via proximal C-H activation of the cyclic carbonate of the hydroxamic acid functionality under protic conditions.
Saxena, Paridhi,Maida, Neha,Kapur, Manmohan
supporting information
p. 11187 - 11190
(2019/09/30)

Consecutive Lossen rearrangement/transamidation reaction of hydroxamic acids under catalyst- and additive-free conditions
The Lossen rearrangement is a classic process for transforming activated hydroxamic acids into isocyanate under basic or thermal conditions. In the current report we disclosed a consecutive Lossen rearrangement/transamidation reaction in which unactivated hydroxamic acids were converted into N-substituted formamides in a one-pot manner under catalyst- and additive-free conditions. One feature of this novel transformation is that the formamide plays triple roles in the reaction by acting as a readily available solvent, a promoter for additive-free Lossen rearrangement, and a source of the formyl group in the final products. Acyl groups other than formyl could also be introduced into the product when changing the solvent to other low molecular weight aliphatic amide derivatives. The solvent-promoted Lossen rearrangement was better understood by DFT calculations, and the intermediacy of isocyanate and amine was supported well by experiments, in which the desired products were obtained in excellent yields under similar conditions. Not only monosubstituted formamides were synthesized from hydroxamic acids, but also N,N-disubstituted formamides were obtained when secondary amines were used as precursors.
Jia, Mengmeng,Zhang, Heng,Lin, Yongjia,Chen, Dimei,Chen, Yanmei,Xia, Yuanzhi
p. 3615 - 3624
(2018/05/26)

Experimental and computational studies on H2O-promoted, Rh-catalyzed transient-ligand-free ortho-C(sp2)-H amidation of benzaldehydes with dioxazolones
An efficient and convenient ligand-free, rhodium-catalyzed ortho-C(sp2)-H amidation of benzaldehydes with dioxazolones using H2O as the key promoter is described. Using this protocol, a wide range of benzaldehyde substrates were selectively amidated in good to excellent yields with broad functional group compatibility. KIE experiments revealed that the C-H bond activation was likely the rate-limiting step. In addition, computational studies indicated that the catalyst precursor interacted with water and dioxazolones to generate the active catalytic species. Notably, the practicality and efficacy of this method were illustrated by a late-stage amidation of an estrone-derived molecule and further transformations of the amidated product.
Ding, Jun,Jiang, Wei,Bai, He-Yuan,Ding, Tong-Mei,Gao, Dafang,Bao, Xiaoguang,Zhang, Shu-Yu
supporting information
p. 8889 - 8892
(2018/08/17)

Tf2NH-Catalyzed Formal [3 + 2] Cycloaddition of Ynamides with Dioxazoles: A Metal-Free Approach to Polysubstituted 4-Aminooxazoles
An unprecedented Tf2NH-catalyzed formal [3 + 2] cycloaddition of ynamides with dioxazoles was developed to construct various polysubstituted 4-aminooxazoles. This approach features a metal-free catalytic bimolecular assembly of oxazole motifs, a low-cost catalyst, exceptionally mild reaction conditions, a very short reaction time, a broad substrate scope, and high efficiency. This metal-free protocol may find applications in pharmaceutical-oriented synthesis.
Zhao, Yingying,Hu, Yancheng,Wang, Chunxiang,Li, Xincheng,Wan, Boshun
p. 3935 - 3942
(2017/04/11)

Product Control using Substrate Design: Ruthenium-Catalysed Oxidative C?H Olefinations of Cyclic Weinreb Amides
A new class of Weinreb amides has been developed as directing groups for the ruthenium-catalysed regioselective oxidative C?H olefination. The new Weinreb amides successfully inhibit the N?O bond reductive cleavage usually associated with the cationic ruthenium system, thereby keeping intact the synthetic utility of Weinreb amides. Mechanistic studies reveal interesting aspects of the directing group capabilities of Weinreb amides when compared to simple amides of similar structures.
Das, Riki,Kapur, Manmohan
supporting information
p. 16986 - 16990
(2016/11/17)

Dioxazoles, a new mild nitrene transfer reagent in gold catalysis: Highly efficient synthesis of functionalized oxazoles
A gold-catalyzed regioselective [3+2] cycloaddition of ynamides with 1,4,2-dioxazoles was developed and offers a novel approach to obtain highly functionalized oxazoles under mild reaction conditions. 1,4,2-Dioxazole was found to act as an efficient N-acyl nitrene equivalent to trigger a facile generation of α-imino gold-carbene intermediate through the elimination of a ketone.
Chen, Ming,Sun, Ning,Chen, Haoyi,Liu, Yuanhong
supporting information
p. 6324 - 6327
(2016/05/19)

Syntheses and evaluation of substituted aromatic hydroxamates and hydroxamic acids that target Mycobacterium tuberculosis
Tuberculosis (TB) continues to remain one of the most threatening diseases in the world. With the emergence of multi-drug resistant (MDR) and extensively drug resistant (XDR) strains, the need to develop new therapies is dire. The syntheses of a focused library of hydroxamates and hydroxamic acids is described, as well as anti-TB activity in the microplate alamar blue assay (MABA). A number of compounds exhibited good activity against Mtb, with notable compounds exhibiting MIC values in the range of 20-0.71 μM. This work suggests that both hydroxamates and their free acids may be incorporated into more complex scaffolds and serve as potential leads for the development of anti-TB agents.
Majewski, Mark W.,Cho, Sanghyun,Miller, Patricia A.,Franzblau, Scott G.,Miller, Marvin J.
p. 4933 - 4936
(2015/10/28)

A two-step tandem reaction to prepare hydroxamic acids directly from alcohols
The first synthesis of hydroxamic acids from alcohols has been developed. Both benzylic and aliphatic alcohols can be tolerated and applied in this reaction. The methodology is economical, environmentally benign and high yielding. This journal is
Dettori, Giovanna,Gaspa, Silvia,Porcheddu, Andrea,De Luca, Lidia
supporting information
p. 4582 - 4585
(2014/06/24)

N-methylimidazole-catalyzed synthesis of carbamates from hydroxamic acids via the lossen rearrangement
An efficient, one-pot, N-methylimidazole (NMI) accelerated synthesis of aromatic and aliphatic carbamates via the Lossen rearrangement is reported. NMI is a catalyst for the conversion of isocyanate intermediates to the carbamates. Moreover, the utility of arylsulfonyl chloride in combination with NMI minimizes the formation of often-observed hydroxamate-isocyanate dimers during the sequence. Under the present conditions, lowering of temperatures is also possible, enabling a mild protocol.
Yoganathan, Sabesan,Miller, Scott J.
supporting information
p. 602 - 605
(2013/04/11)

HISTONE DEACETYLASE INHIBITORS AND METHODS OF USE THEREOF
The present invention provides novel compounds for inhibiting histone deacetylases, and pharmaceutically acceptable salts and derivatives thereof. The present invention further provides methods for treating disorders regulated by histone deacetylase activity (e.g., proliferative diseases, cancer, inflammatory diseases, protozoal infections, hair loss, etc.) comprising administering a therapeutically effective amount of a compound of the invention to a subject in need thereof. The present invention also provides methods for preparing compounds of the invention.
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(2012/09/10)

Carbonyldiimidazole-mediated lossen rearrangement
[Chemical Equation Presented] Carbonyldiimidazole (CDI) was found to mediate the Lossen rearrangement of various hydroxamic acids to isocyanates. This process is experimentally simple and mild, with imidazole and CO 2 being the sole stoichiometric byproduct. Significant for large-scale application, the method avoids the use of hazardous reagents and thus represents a green alternative to standard processing conditions for the Curtius and Hofmann rearrangements.
Dube, Pascal,Fine Nathel, Noah F.,Vetelino, Michael,Couturier, Michel,Aboussafy, Claude Larrivee,Pichette, Simon,Jorgensen, Matthew L.,Hardink, Mark
supporting information; body text
p. 5622 - 5625
(2010/03/02)

New C-3′ hydroxamate-substituted and more lipophilic cyclic hydroxamate cephalosporin derivatives as a potential new generation of selective antimicrobial agents
Syntheses of a series of new C-3′ hydroxamate-substituted cephalosporin derivatives with potent antibacterial and media-dependent anti-TB activity are described. The Royal Society of Chemistry 2006.
Miller, Marvin J.,Zhao, Gaiying,Vakulenko, Sergei,Franzblau, Scott,Moellmann, Ute
p. 4178 - 4185
(2008/09/20)

N-linked hydroxylamine resin: Solid-phase synthesis of hydroxamic acids
A novel hydroxylamine resin for solid-phase synthesis of hydroxamic acids is described. Its facile application is illustrated by the solid-phase synthesis of various hydroxamic acids. Cleavage is induced under acidic conditions by treatment with trifluoroacetic acid, providing hydroxamic acids in high purity and good yields. Copyright Taylor & Francis, Inc.
Yin, Zheng,Low, KaySiang,Lye, PekLing
p. 2945 - 2950
(2007/10/03)

Linear free-energy relationships in the protonation equilibria and acid-base catalysed reaction of 4-substituted benzohydroxamic acids
As part of our investigations on the structure-reactivity relationships in protonation and hydrolysis of hydroxamic acids, we have now studied a series of 4-substituted benzohydroxamic acids (4-X-C6H4.CO.NH(OH), with X=H, Me, OMe, Cl, Br, F and NO2) in aqueous sulfuric acid. Good correlation was observed pointing out the validity of the Hammett equation. The protonation constant, ionization constant and rate constant for acid- and base-catalysed hydrolysis reactions seems are to be related in a linear free-energy (LEER) fashion.
Ghosh, Kallol K.,Tamrakar, Pankaj
p. 1153 - 1168
(2007/10/03)