6402-09-1Relevant articles and documents
4-Phosphoryl Pyrazolones for Highly Selective Lithium Separation from Alkali Metal Ions
Du, Hao,Hennersdorf, Felix,Lindoy, Leonard F.,Schaper, Gerrit,Steup, Johannes,Weigand, Jan J.,Wenzel, Marco,Zhang, Jianfeng,Zheng, Shili
supporting information, (2021/11/10)
Effective receptors for the separation of Li+ from a mixture with other alkali metal ions under mild conditions remains an important challenge that could benefit from new approaches. In this study, it is demonstrated that the 4-phosphoryl pyrazolones, HL2-HL4, in the presence of the typical industrial organophosphorus co-ligands tributylphosphine oxide (TBPO), tributylphosphate (TBP) and trioctylphosphine oxide (TOPO), are able to selectively recognise and extract lithium ions from aqueous solution. Structural investigations in solution as well as in the solid state reveal the existence of a series of multinuclear Li+ complexes that include dimers (TBPO, TBP) as well as rarely observed trimers (TOPO) and represent the first clear evidence for the synergistic role of the co-ligands in the extraction process. Our findings are supported by detailed NMR, MS and extraction studies. Liquid-liquid extraction in the presence of TOPO revealed an unprecedented high Li+ extraction efficiency (78 %) for HL4 compared to the use of the industrially employed acylpyrazolone HL1 (15 %) and benzoyl-1,1,1-trifluoroacetone (52 %) extractants. In addition, a high selectivity for Li+ over Na+, K+ and Cs+ under mild conditions (pH ～8.2) confirms that HL2-HL4 represent a new class of ligands that are very effective extractants for use in lithium separation.
Catalytic System-Controlled Divergent Reaction Strategies for the Construction of Diversified Spiropyrazolone Skeletons from Pyrazolidinones and Diazopyrazolones
Fang, Feifei,Han, Xu,Hu, Shulei,Li, Chunpu,Liu, Hong,Wang, Qian,Wang, Run,Zhou, Yu
supporting information, p. 21327 - 21333 (2021/08/20)
A catalytic system-controlled divergent reaction strategy was here reported to construct four types of intriguing spiroheterocyclic skeletons from simple and readily available starting materials via a precise chemical bond activation/[n+1] annulation cascade. The tetraazaspiroheterocyclic and trizazspiroheterocyclic scaffolds could be independently constructed by a selective N?N bond activation/[n+1] annulation cascade, a C(sp2)-H activation/[4+1] annulation and a novel tandem C(sp2)-H/C(sp3)?H bond activation/[4+1] annulation strategy, along with a broad scope of substrates, moderate to excellent yields and valuable transformations. More importantly, in these transformations, we are the first time to capture a N?N bond activation and a C(sp3)?H bond activation of pyrazolidinones under different catalytic system.
Rhodium-Catalyzed [4+2] Annulation of N-Aryl Pyrazolones with Diazo Compounds To Access Pyrazolone-Fused Cinnolines
Dhole, Sandip,Huang, Wan-Wen,Huang, Ying-Ti,Lin, Chih-Yu,Sun, Chung-Ming
supporting information, p. 4984 - 4992 (2021/09/28)
An efficient synthesis of novel dinitrogen-fused heterocycles such as pyrazolo[1,2-a]cinnoline derivatives have been accomplished by the rhodium(III)-catalyzed reaction of N-arylpyrazol-5-ones with α-diazo compounds. This reaction proceeds through a cascade C?H activation/intramolecular cyclization with a broad substrate scope. Furthermore, this protocol is successfully extended to the unusual phosphorus-containing α-diazo compounds and cyclic diazo compounds as the cross-coupling partners to deliver the two new kinds of pyrazolo[1,2-a]cinnolinones. The control experiments were performed to reveal insight into the mechanism of this reaction, involving reversible C?H activation, migratory insertion of the diazo compound, and cascade cyclization as the key steps of the transformation. Moreover, gram-scale synthesis and further transformation of the target product demonstrate the synthetic utility of the present protocol.
Metal-Free Direct C–H Thiolation and Thiocyanation of Pyrazolones
Kittikool, Tanakorn,Yotphan, Sirilata
supporting information, (2020/02/13)
Metal-free approach for direct C–H thiolation and thiocyanation of N-substituted pyrazolones with disulfides and thiocyanate salts, respectively, are developed. These reactions allow the C–S bond coupling to proceed effectively under mild conditions, providing useful and convenient methods for preparation of a series of 4-thio-substituted pyrazolone analogues, which have potential applications in organic, medicinal and material chemistry. Preliminary mechanistic investigation suggested that radical processes are likely to involve in these transformations.
Tuned structure and DNA binding properties of metal complexes based on a new 4-acylpyrazolone derivative
Xi, Wei,Song, Fu-Qiang,Xia, Xue-Li,Song, Xue-Qin
, p. 2281 - 2290 (2020/02/20)
It is common knowledge that the spatial structure of substrates is the major influencing factor in DNA binding. To tune the binding affinity of DNA, a new 4-acylpyrazolone derivative ligand, (2-hydroxy-N′-((5-hydroxy-3-methyl-1-(4-nitrophenyl)-4,5-dihydro-1H-pyrazol-4-yl)(phenyl)methylene)benzohydrazide) (H2L) and its three complexes have been prepared and well characterized. Reaction of H2L with CuCl2 resulted in a mononuclear compound with tetra-coordinated quadrilateral plane, [Cu(HL)Cl] (1). When H2L was coordinated to Cu(OAc)2, a dinuclear Cu(ii) compound with chemical formula of [Cu2L2(CH3OH)2]·CH3OH (2) was obtained, and the coordination geometry of Cu(ii) is a square pyramid. Upon assembly of H2L with Mn(OAc)2, a quite different dinuclear compound with chemical composition of [Mn2L2(O CH3)2(H2O)2]·CH3OH (3) was afforded, where Mn(iii) displayed distorted octahedral configurations. DNA binding studies were performed on H2L and its three complexes by means of electron absorption titration and EB-DNA competition experiments, and the results indicate they all bind DNA in an intercalation mode, and their binding affinity follows the order of 1 > 2 > 3 > H2L. In addition, time-dependent density functional theory (TD-DFT) calculations were performed for H2L and its three complexes to better clarify the electronic transitions in the UV-vis spectra.
Diversity-Oriented Synthesis of Spiropentadiene Pyrazolones and 1 H-Oxepino[2,3- c]pyrazoles from Doubly Conjugated Pyrazolones via Intramolecular Wittig Reaction
Khairnar, Pankaj V.,Wu, Chi-Yi,Lin, Yi-Fang,Edukondalu, Athukuri,Chen, Yi-Ru,Lin, Wenwei
supporting information, p. 4760 - 4765 (2020/06/25)
An efficient method for the diversity-oriented synthesis of spiropentadiene pyrazolones and 1H-oxepino[2,3-c]pyrazoles is reported. The methodology attributes O-acylation of phosphorus zwitterions which were formed by a tandem phospha-1,6-addition of PBu3 to α,β,γ,δ-unsaturated pyrazolones, further generating betaine intermediates that preferentially resulted in the aforementioned cyclic products in a diversity-oriented manner. The mechanistic investigations revealed that formation of the betaines is the key step to provide the products via an intramolecular Wittig reaction or an unprecedented δ-C-acylation/cyclization/Wittig reaction.
Organophosphane-catalyzed direct β-acylation of 4-arylidene pyrazolones and 5-arylidene thiazolones with acyl chlorides
Khairnar, Pankaj V.,Su, Yin-Hsiang,Chen, Yung-Chang,Edukondalu, Athukuri,Chen, Yi-Ru,Lin, Wenwei
supporting information, p. 6868 - 6872 (2020/09/15)
An efficient method for the direct β-acylation of arylidene pyrazolones and thiazolones with acyl chlorides in the presence of a base catalyzed by organophosphanes is reported. A variety of functionalized 4-arylidene pyrazolone and 5-arylidene thiazolone derivatives were prepared under metal-free and mild conditions via a tandem phospha-Michael addition/O-acylation/intramolecular cyclization/rearrangement sequence. Our mechanistic investigations revealed that the reaction is highly stereospecific to provide exclusively cis-isomers, and the methodology can also be scaled up with similar efficacy.
Structure-activity relationships of pyrazole-4-carbodithioates as antibacterials against methicillin–resistant Staphylococcus aureus
Majed, Hiwa,Johnston, Tatiana,Kelso, Celine,Monachino, Enrico,Jergic, Slobodan,Dixon, Nicholas E.,Mylonakis, Eleftherios,Kelso, Michael J.
supporting information, p. 3526 - 3528 (2018/10/15)
Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of serious hospital-acquired infections and is responsible for significant morbidity and mortality in residential care facilities. New agents against MRSA are needed to combat rising resistance to current antibiotics. We recently reported 5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC) as a new bacteriostatic agent against MRSA that appears to act via a novel mechanism. Here, twenty nine analogs of HMPC were synthesized, their anti-MRSA structure-activity relationships evaluated and selectivity versus human HKC-8 cells determined. Minimum inhibitory concentrations (MIC) ranged from 0.5 to 64 μg/mL and up to 16-fold selectivity was achieved. The 4-carbodithioate function was found to be essential for activity but non-specific reactivity was ruled out as a contributor to antibacterial action. The study supports further work aimed at elucidating the molecular targets of this interesting new class of anti-MRSA agents.
DABCO-catalyzed silver-promoted direct thiolation of pyrazolones with diaryl disulfides
Thupyai, Akkharaphong,Pimpasri, Chaleena,Yotphan, Sirilata
supporting information, p. 424 - 432 (2018/02/06)
A highly efficient protocol for a direct thiolation of N-substituted pyrazolones with diaryl disulfides is described. Using a combination of DABCO and silver(i) acetate, the C-S bond formation proceeds smoothly at room temperature under mild and easy to handle conditions. This synthetic strategy offers a convenient and direct modification of antipyrine and other pyrazolone substrates, giving a series of aryl sulfide-substituted pyrazolone products in moderate to excellent yields.
Copper/Persulfate-Promoted Oxidative Decarboxylative C?H Acylation of Pyrazolones with α-Oxocarboxylic Acids: Direct Access to 4-Acylpyrazolones under Mild Conditions
Kittikool, Tanakorn,Thupyai, Akkharaphong,Phomphrai, Khamphee,Yotphan, Sirilata
supporting information, p. 3345 - 3355 (2018/09/10)
A facile and efficient oxidative C?H acylation of N-substituted pyrazolones using α-oxocarboxylic acids as an acyl group source was developed. A combination of Cu(OAc)2 and K2S2O8 enables the reaction to proceed smoothly under air and provides a wide array of 4-acylpyrazolone products in moderate to excellent yields. The mechanism of this transformation is believed to proceed via a copper-induced decarboxylation to form the acyl-copper species. This method provides a convenient and useful route for a direct installation of an acyl moiety into bioactive pyrazolone derivatives, which can be further utilized in many applications. (Figure presented.).
