- Solid-state and solution structures of a series of [(HBPz3Me2)Rh(CO)(PR3)] and [(HBPz3Me2,4Cl)Rh(CO)(PR3)] complexes
-
Addition of 1 equiv. of a phosphane or phosphite ligand to the κ3-bonded [TpMe2Rh(CO)2] and [TpMe2,4ClRh(CO)2] dicarbonyl precursors gives the monosubstituted complexes [TpRh(CO)L]. The X-ray crystal
- Malbosc, Fran?ois,Chauby, Valérie,Serra-Le Berre, Carole,Etienne, Michel,Daran, Jean-Claude,Kalck, Philippe
-
-
Read Online
- Site-Selective C–H Functionalization of (Hetero)Arenes via Transient, Non-symmetric Iodanes
-
Fosu, Hambira, and colleagues describe the direct C–H functionalization of medicinally relevant arenes or heteroarenes. This strategy is enabled by transient generation of reactive, non-symmetric iodanes from anions and PhI(OAc)2. The site-selective incorporation of Cl, Br, OMs, OTs, and OTf to complex molecules, including within medicines and natural products, can be conducted by the operationally simple procedure included herein. A computational model for predicting site selectivity is also included. The discovery of new medicines is a time- and labor-intensive process that frequently requires over a decade to complete. A major bottleneck is the synthesis of drug candidates, wherein each complex molecule must be prepared individually via a multi-step synthesis, frequently requiring a week of effort per molecule for thousands of candidates. As an alternate strategy, direct, post-synthetic functionalization of a lead candidate could enable this diversification in a single operation. In this article, we describe a new method for direct manipulation of drug-like molecules by incorporation of motifs with either known pharmaceutical value (halides) or that permit subsequent conversion (pseudo-halides) to medicinally relevant analogs. This user-friendly strategy is enabled by combining commercial iodine reagents with salts and acids. We expect this simple method for selective, post-synthetic incorporation of molecular diversity will streamline the discovery of new medicines. A strategy for C–H functionalization of arenes and heteroarenes has been developed to allow site-selective incorporation of various anions, including Cl, Br, OMs, OTs, and OTf. This approach is enabled by in situ generation of reactive, non-symmetric iodanes by combining anions and bench-stable PhI(OAc)2. The utility of this mechanism is demonstrated via para-selective chlorination of medicinally relevant arenes, as well as site-selective C–H chlorination of heteroarenes. Spectroscopic, computational, and competition experiments describe the unique nature, reactivity, and selectivity of these transient, unsymmetrical iodanes.
- Fosu, Stacy C.,Hambira, Chido M.,Chen, Andrew D.,Fuchs, James R.,Nagib, David A.
-
supporting information
p. 417 - 428
(2019/02/14)
-
- Cu1.5PMo12O40-catalyzed condensation cyclization for the synthesis of substituted pyrazoles
-
A convenient and direct approach has been developed for the preparation of pyrazole derivatives by the condensation cyclization of hydrazines/hydrazide and 1,3-diketones in the presence of Cu1.5PMo12O40 (0.33?mol%) under mild conditions (r.t.-60?°C, 10–30?min). Notably, the reaction was found to be scalable as 99% yield was obtained when the reaction was performed at a 5-mmol scale. This solvent-free and halogen-free catalytic system represents an effective economic and environmentally friendly method for the construction of pyrazoles.
- Yang, Guo-Ping,He, Xing,Yu, Bing,Hu, Chang-Wen
-
-
- A two-valence sulfonyl isoxazole derivatives and use thereof
-
The invention discloses a bi-titer sulfonyl isoxazole derivative in the technical field of organic compound weedicides, and application thereof. The bi-titer sulfonyl isoxazole derivative has a molecular structural formula shown as a general formula I. The invention further discloses a preparation method of the bi-titer sulfonyl isoxazole derivative. The bi-titer sulfonyl isoxazole derivative has very high activity of inhibiting weed growth and killing and removing weeds, and can be used in agricultural production, and is classified as a novel active component for weedicides.
- -
-
-
- Synthesis and characterization of some symmetrical substituted 1-(2-chloroethyl)pyrazole-based chalcogenides
-
The present paper describes the synthesis of some symmetrical substituted 1-(2-chloroethyl) pyrazole-based dichalcogenides and monochalcogenides by reacting different 3,4,5-trisubstituted 1-(2-chloroethyl) pyrazole derivatives with in situ prepared Na2E2 (E = S, Se, Te) and sodium hydrogen selenide, respectively. All compounds were fully characterized by different spectroscopic techniques, namely, IR, 1H, 13C, 77Se nuclear magnetic resonance, and mass spectrometry. X-ray crystal structure determination of 1,2-bis(2-(4-bromo-3,5-dimethyl-1H-pyrazol-1-yl)ethyl)diselane (10b) reveals intermolecular Se·N·H interactions between two molecules.
- Pundir,Mehta,Mobin,Bhasin
-
-
- A mild halogenation of pyrazoles using sodium halide salts and Oxone
-
A mild, inexpensive, and operationally simple pyrazole halogenation method utilizing Oxone and sodium halide salts is reported. This work documents 17 examples of alkyl, aryl, allyl, and benzyl substituted 4-chloro and 4-bromopyrazoles, obtained in up to 93% yield. Reactions are performed in water under ambient conditions and generation of organic byproducts is avoided.
- Olsen, Kathryn L.,Jensen, Matthew R.,MacKay, James A.
-
supporting information
p. 4111 - 4114
(2017/09/29)
-
- WATER-SOLUBLE PYRAZOLE DERIVATIVES AS CORROSION INHIBITORS
-
Disclosed are nitrogen-containing heterocyclic compounds of relatively low aquatic toxicity and methods of using the heterocyclic compounds as corrosion inhibitors. The present method is used to inhibit corrosion of a metal surface in contact with an aqueous system using pyrazole derivatives, and provides enhanced protection against corrosion of metals in aqueous systems. The method comprises the use of corrosion inhibitors that are generally resistant to halogen attack and provide good corrosion resistance in the presence of oxidizing halogen-based biocides. Formulations comprising pyrazole derivatives are also disclosed.
- -
-
Paragraph 0113
(2016/12/22)
-
- A combined experimental and natural bonding orbital charges study on the one-pot regioselective synthesis of 4-chloropyrazoles
-
The mechanism of a DMF-catalysed electrophilic/nucleophilic chlorination of pyrazole is illustrated with the aid of calculations of the natural bonding orbital charges. Its high regioselectivity and good functionality tolerance of nine pyrazole substrates
- Li, Yi,Liu, Yuanyuan,Xu, Guanghui,Chen, Kai,He, Guangke,Huang, Bin
-
p. 658 - 661
(2015/01/16)
-
- Design, practical synthesis, and biological evaluation of novel 6-(Pyrazolylmethyl)-4-quinoline-3-carboxylic acid derivatives as HIV-1 integrase inhibitors
-
A series of novel 6-(pyrazolylmethyl)-4-oxo-4H-quinoline-3-carboxylic acid derivatives bearing different substituents on the N-position of quinoline ring were designed and synthesized as potential HIV-1 integrase (IN) inhibitors, based on the structurally related GS-9137 scaffold. The structures of all new compounds were confirmed by 1H-NMR, 13C-NMR and ESI (or HRMS) spectra. Detailed synthetic protocols and the anti-IN activity studies are also presented.
- Hu, Liming,Yan, Song,Luo, Zaigang,Han, Xiao,Wang, Yujie,Wang, Zhanyang,Zeng, Chengchu
-
p. 10652 - 10666
(2012/11/07)
-
- Organic compounds
-
There are described cyclohexyl amide derivatives useful as corticotropin releasing factor (CRF1) receptor antagonists.
- -
-
Page/Page column 70
(2010/03/02)
-
- α-Substituted boron difluoride acetylacetonates
-
By treatment of α-substituted acetylacetone derivatives with boron trifluoride etherate a series of earlier unknown boron difluoride complexes is obtained. The series includes binuclear complexes containing boron in the chelate fragment connected via sulfur or selenium atom. Gas chromatographic and spectral characteristics of the obtained compounds were investigated. By means of chromato-mass spectrometry their reaction with hydrazine in acidic and alkaline media was studied.
- Svistunova,Fedorenko
-
body text
p. 1515 - 1523
(2009/06/28)
-
- N-benzoylpyrazoles are novel small-molecule inhibitors of human neutrophil elastase
-
Human neutrophil elastase (NE) plays an important role in the pathogenesis of pulmonary disease. Using high-throughput chemolibrary screening, we identified 10 N-benzoylpyrazole derivatives that were potent NE inhibitors. Nine additional NE inhibitors were identified through further screening of N-benzoylpyrazole analogues. Evaluation of inhibitory activity against a range of proteases showed high specificity for NE, although several derivatives were also potent inhibitors of chymotrypsin. Analysis of reaction kinetics and inhibitor stability revealed that N-benzoylpyrazoles were pseudoirreversible competitive inhibitors of NE. Structure-activity relationship (SAR) analysis demonstrated that modification of N-benzoylpyrazole ring substituents modulated enzyme selectivity and potency. Furthermore, molecular modeling of the binding of selected active and inactive compounds to the NE active site revealed that active compounds fit well into the catalytic site, whereas inactive derivatives contained substituents or conformations that hindered binding or accessibility to the catalytic residues. Thus, N-benzoylpyrazole derivatives represent novel structural templates that can be utilized for further development of efficacious NE inhibitors.
- Schepetkin, Igor A.,Khlebnikov, Andrei I.,Quinn, Mark T.
-
p. 4928 - 4938
(2008/03/13)
-
- Halogenation of pyrazoles using N-halosuccinimides in CCl4 and in water
-
Reaction of pyrazoles with N-halosuccinimides (NXS, X=Br, Cl) in either CCl4 or water gave 4-halopyrazoles in excellent yields. The reaction was carried out under mild conditions and did not require any catalysts or special precautions. The reaction provides an efficient method for 4-C halogenation of pyrazoles. Copyright Taylor & Francis Group, LLC.
- Zhao, Zhi-Gang,Wang, Zhong-Xia
-
p. 137 - 147
(2007/10/03)
-
- A mild and efficient method for halogenation of 3,5-dimethyl pyrazoles by ultrasound irradiation using N-halosuccinimides
-
The 4-halo-3,5-dimethyl pyrazoles have been synthetisized in good yields in short reaction times in the absence of a catalyst by reaction of 3,5-dimethyl pyrazoles with N-halosuccinimides (NBS, NCS and NIS) under ultrasound irradiation. Finally, the halogenation of pyrazoles with Br2, IC1 and I2 was showed in similar conditions.
- Stefani, Hélio A.,Pereira, Claudio M. P.,Almeida, Roberta B.,Braga, Rodolpho C.,Guzen, Karla P.,Cella, Rodrigo
-
p. 6833 - 6837
(2007/10/03)
-
- Synthesis of β-tosylethylhydrazine and its use in preparation of N-protected pyrazoles and 5-aminopyrazoles
-
β-Tosylethylhydrazine (6) can be prepared efficiently in one step from commercially available p-tolyl vinyl sulfone (7) and hydrazine hydrate. This hydrazine reacts with both 1,3-diketones and conjugated ynones in glacial acetic acid to provide a variety of N-tosylethyl-protected (TSE) pyrazoles in good yields. The TSE group can be removed from the pyrazoles using potassium t-butoxide in THF at -30°C-rt. In addition, hydrazine 6 condenses with β-ketonitriles and β-aminoacrylonitriles to afford 5-aminopyrazoles, which can be deprotected by brief treatment with NaOEt in EtOH/DMSO at 45°C.
- Dastrup, David M.,Yap, Amy H.,Weinreb, Steven M.,Henry, James R.,Lechleiter, Andrew J.
-
p. 901 - 906
(2007/10/03)
-
- Gas-chromatographic study of hydrazine reaction with metal β-diketonates
-
When treated with hydrazine, metal β-diketonates undergo decomposition to form the corresponding pyrazoles, irrespective of the kinetic stability of the chelates. With substituted metal chelates, the main reaction products are pyrazoles bearing in positio
- Svistunova,Shapkin,Nikolaeva
-
p. 899 - 900
(2007/10/03)
-
- Pyrazole as a leaving group in nucleophilic substitution in 3,6-bis(3,5-dimethyl-1-pyrazolyl)-1,2,4,5-tetrazines
-
Nucleophilic substitution by N-nucleophiles of the 3,5-dimethyl-1-pyrazolyl group in 3,6-bis-(3,5-dimethyl-1-pyrazolyl)-1,2,4,5-tetrazine is discussed.
- Latosh,Rusinov,Ganebnykh,Chupakhin
-
p. 1363 - 1371
(2007/10/03)
-
- Metal pyrazolate polymers. Part 3. Synthesis and study of Cu(I) and Cu(II) complexes of 4-Xdmpz (where X = H, Cl, Br, I, and CH3 for Cu(I) and X = H, Cl, Br, and CH3 for Cu(II); dmpz = 3,5-dimethylpyrazolate)
-
The copper(I) complexes 3 (where X = H, Cl, Br, I, and CH3; dmpz = 3,5-dimethylpyrazolate) and the copper(II) complexes x have been synthesized and characterized.Qualitative solubility, infrared spectroscopic, and differential scanning calorimetric studies are reported for all complexes.Mass spectra support trimeric formulations for the copper(I) complexes.Scanning electron micrographs and powder X-ray diffractograms have been reported for the copper(II) compounds.Electronic and EPR spectroscopic studies as well as magnetic susceptibilitystudies from 2 to 300 K are also reported for the copper(II) compounds, which are proposed to have polymeric chain structures.The magnetic data reveal strong antiferromagnetic interactions in all four copper(II) compounds.The data have been analysed employing an isotropic Heisenberg model for antiferromagnetic coupling in extended chain polymers.Values of the exchange coupling constant, J, are determined as -58, -61, -66, and -66 cm-1 for the X = H, CH3, Cl, and Br complexes respectively.The X = Cl compound exhibits an abrupt decrease in magnetic susceptibility below 40 K and possible causes of this anomalous behaviour are discussed.
- Ehlert, Martin K.,Storr, Alan,Thompson, Robert C.
-
p. 1121 - 1128
(2007/10/02)
-
- Reactions of N-Aminopyrazoles with Halogenating Reagents and Synthesis of 1,2,3-Triazines
-
Reactions of N-aminopyrazoles with halogenating reagents (Cl2, Br2, I2, BrCl, ICl, IBr, N-chlorosuccinimide, and N-bromosuccinimide) were examined.Some of these reagents preferentially lead to oxidation of the amino group to give the corresponding 1,2,3-triazines as major products, while others mainly gave either or both of 1-amino-4-halopyrazoles and 5-halo-1,2,3-triazines as the result of halogenation of the 4-position of the pyrazole ring prior to the oxidation of the amino group.In some cases, the oxidation of the amino group and the halogenation of the pyrazole ring proceeded concurrently to form not only the unhalogenated triazines but also the 1-amino-4-halopyrazoles and the 5-halotriazines.Various reagents and reaction conditions were explored to utilize the reaction for the synthesis of halogenated and unhalogenated 1,2,3-triazines.Keywords - 1,2,3-triazine; halo-1,2,3-triazine; pyrazole; 1-aminopyrazole; 1-aminohalopyrazole; synthesis; oxidation; halogenation; ring expansion
- Ohsawa, Akio,Kaihoh, Terumitsu,Itoh, Takashi,Okada, Mamiko,Kawabata, Chikako,et al.
-
p. 3838 - 3848
(2007/10/02)
-
- STATISTICAL ANALYSIS OF ELECTRONIC ABSORPTION SPECTRA OF PYRAZOLES. I. N-UNSUBSTITUTED PYRAZOLES WITH IDENTICAL SUBSTITUENTS AT POSITIONS 3 AND 5
-
The main absorption band (wavelength and wavenumber) of 30 N-unsubstituted pyrazoles have been statistically analyzed by means of a "de novo" method.An empirical model which accounts for the 99.8percent of explained variance has been found.The predictive ability of this model has been tested by synthesizing the unknown 4-t-butylpyrazole and measuring its UV absorption (λmax calc. 217.5 nm; λmax exp. 210 nm).
- Cativiela, Carlos,Laureiro, Jose Ignacio Garcia,Elguero, Jose
-
p. 119 - 126
(2007/10/02)
-