- N-triflyl-propiolamides: Preparation and transamidation reactions
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N-Trifluoromethylsulfonyl-propiolamides have been prepared by two methods: a) N-triflation of secondary acetylenic carboxanilides, prepared in two steps from terminal alkynes, with triflic anhydride (Tf2O) and b) from terminal alkynes and an aryl or alkyl isocyanate followed by Tf2O in a consecutive one-pot reaction. The title compounds are bench-stable and insensitive to water and alcohols but amenable to transamidation reactions with a wide range of amine nucleophiles. Conversely, they are excellent reagents for the propynoylation of ammonia, primary and secondary amines, anilines, and hydrazines.
- Fiore, Vito A.,Maas, Gerhard
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p. 3586 - 3595
(2019/05/27)
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- Palladium-catalyzed carbonylative coupling of α-chloroketones with hydrazines: a simple route to pyrazolone derivatives
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A range of pyrazol-5-one and pyrazol-3-one derivatives has been synthesized in a single step via a palladium-catalyzed carbonylation of aromatic or aliphatic α-chloroketones, in the presence of aromatic or aliphatic hydrazines. A reaction mechanism, explaining the observed regioselectivity, has been also discussed.
- Capua, Martina,Granito, Catia,Perrone, Serena,Salomone, Antonio,Troisi, Luigino
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p. 3363 - 3367
(2016/07/11)
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- Synthesis, crystal structure, and fungicidal activity of novel 1,5-diaryl-1H-pyrazol-3-Oxy derivatives containing oxyacetic acid or oxy(2-thioxothiazolidin-3-yl)ethanone moieties
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A series of novel 1,5-diaryl-1H-pyrazol-3-oxy derivatives containing oxyacetic acid or oxy(2-thioxothiazolidin-3-yl)ethanone moieties were prepared from methyl 3-arylacrylates via a serial of reactions included addition-cyclization, oxidation, substitution, hydrolysis, and condensation. Their structures were confirmed by 1H-NMR, 13C-NMR, IR, and elemental analysis. In addition, the crystal structure of the compound 2-(1,5-diphenyl-1H-pyrazol-3-yloxy)-1-(2-thioxothiazolidin-3-yl)ethanone was determined by single crystal X-ray diffraction analysis. Bioassay results indicated that the compound 2-(5-(4-chlorophenyl)-1-phenyl-1H-pyrazol-3-yloxy)- 1-(2-thioxo-thiazolidin-3-yl)ethanone exhibited moderate inhibitory activity against Gibberella zeae at the dosage of 10 μg mL-1.
- Liu, Yuanyuan,He, Guangke,Kai, Chen,Li, Yufeng,Zhu, Hongjun
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p. 1370 - 1375
(2013/02/22)
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- DMF-catalyzed direct and regioselective C-H functionalization: Electrophilic/nucleophilic 4-halogenation of 3-oxypyrazoles
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A novel, straightforward, and highly regioselective 4-chlorination of 3-oxypyrazole derivatives in boiling thionyl chloride (SOCl2) in the presence of catalytic N,N-dimethylformamide (DMF) has been developed. This reaction likely proceeds through a DMF-catalyzed electrophilic/nucleophilic chlorination mechanism and involves electrophilic attack by SOCl2 and nucleophilic substitution by Cl- as the key steps. Based on this mechanism, the corresponding 4-bromination and 4-iodination of 3-oxypyrazoles have also been achieved in good yield by adding Br- and I -, respectively, to the reaction system. This halogenation method enables quick access to many original 4-halo-3-oxypyrazole series. A novel DMF-catalyzed electrophilic/nucleophilic 4-halogenation of 3-oxypyrazole derivatives has been developed. This halogenation procedure provides quick access to many novel 4-halo-3-oxypyrazole series.
- Liu, Yuanyuan,He, Guangke,Chen, Kai,Jin, Yin,Li, Yufeng,Zhu, Hongjun
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p. 5323 - 5330
(2011/11/13)
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- Synthesis, crystal structure, and fungicidal activity of novel 1,5-Diaryl-1H-pyrazol-3-oxyacetate derivatives
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A series of ethyl 2-(1,5-diaryl-1H-pyrazol-3-yloxy)acetate derivatives (5a-5i) have been efficiently synthesized by the reaction of 1,5-diaryl-1H-pyrazol-3-ols (4a-4i) with ethyl 2-bromoacetate. The structures of the newly synthesized compounds were characterized by 1H NMR spectra and elemental analysis, and the crystal structure of the compound ethyl 2-(5-(4-chlorophenyl)-1-phenyl-1H-pyrazol-3-yloxy)acetate (5c) was determined by single crystal X-ray diffraction analysis. The compound 5c belongs to triclinic system with space group P(-1), a = 5.8170(12) A, b = 11.804(2) A, c = 12.783(2) A, α = 83.89(2)°, β = 89.24(3)°, γ = 89.73(3)°, Formula weight: 356.80, Triclinic V = 872.7(3) A3, Dc = 1.358 mg/m3, Z = 2, F (000) = 372. Bioassay results indicated that the compound ethyl 2-(5-(4-fluorophenyl)-1- phenyl-1H-pyrazol-3-yloxy)acetate (5d) exhibited moderate inhibitory activity against Gibberella zeae at the dosage of 10 μg/mL.
- Liu, Yuanyuan,Shi, Hong,Li, Yufeng,Zhu, Hongjun
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experimental part
p. 897 - 902
(2010/10/18)
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- 5-Iodo-3-ethoxypyrazoles: An entry point to new chemical entities
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Our program, which has focused on the preparation of new pyrazole derivatives, has led us to report here an original and simplified preparation of ethyl 3-ethoxy-lW-pyrazole-4-carboxylate. This is based on the reaction of hydrazine monohydrochloride and diethyl 2-(ethoxymethylene)malonate. Further transformations of this key compound allowed the preparation of the two possible iodinated isomers, namely, 3-ethoxy-4-iodo- and 3-ethoxy-5-iodo-1H-pyrazole. These compounds have opened the way to a quick access to many original pyrazole series. As an illustration, we report here on the selectivity of N-arylation, by using the Lam and Cham method, the C4- and C5-arylation of some of these 3-ethoxy-pyrazole derivatives by using the Suzuki-Miyaura reaction, and C5-benzylation reactions by means of the Negishi reaction. This was followed by hydrolysis of the ethoxy group, which led to the corresponding pyrazol-3-one derivatives. As a conclusion of this work, we conducted an investigation into the regiochemistry of the condensation between diethyl 2-(ethoxymethylene) malonate and the hydrochloride salts of methyl, benzyl, or phenyl hydrazine.
- Guillou, Sandrine,Janin, Yves L.
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body text
p. 4669 - 4677
(2010/08/06)
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- Reactions of 4-alkylidene (arylidene)-1-phenylpyrazolidine-3,5-dione
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Reactions of 4-alkylidene(arylidene)-1-phenylpyrazolidine-3,5-dione with oxidizing (chromium trioxide/acetic acid) as well as with reducing (sodium borohydride/methanol) agents were carried out. Phenylhydrazine reacted with 4-arylidene-1-phenylpyrazolidine-3,5-diones via fission of exo C=C bond to give 1-phenylpyrazolidine-3,5-dione and the corresponding aryl hydrazones.
- Metwally, Saoud A. M.,Mohamed, Thanaa A.,Moustafa, Osama S.,El-Ossaily, Yasser A.
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p. 1131 - 1137
(2008/09/19)
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- Synthesis and biological evaluation of novel pyrazoles and indazoles as activators of the nitric oxide receptor, soluble guanylate cyclase
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Database searching and compound screening identified 1-benzyl-3-(3-dimethylaminopropyloxy)-indazole (benzydamine, 3) as a potent activator of the nitric oxide receptor, soluble guanylate cyclase. A comprehensive structure-activity relationship study surrounding 3 clearly showed that the indazole C-3 dimethylaminopropyloxy substituent was critical for enzyme activity. However replacement of the indazole ring of 3 by appropriately substituted pyrazoles maintained enzyme activity. Compounds were evaluated for inhibition of platelet aggregation and showed a general lipophilicity requirement. Aryl-substituted pyrazoles 32, 34, and 43 demonstrated potent activation of soluble guanylate cyclase and potent inhibition of platelet aggregation. Pharmacokinetic studies in rats showed that compound 32 exhibits modest oral bioavailability (12%) Furthermore 32 has an excellent selectivity profile notably showing no significant inhibition of phosphodiesterases or nitric oxide synthases.
- Selwood,Brummell,Budworth,Burtin,Campbell,Chana,Charles,Fernandez,Glen,Goggin,Hobbs,Kling,Liu,Madge,Meillerais,Powell,Reynolds,Spacey,Stables,Tatlock,Wheeler,Wishart,Woo
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- RECYCLIZATION REACTIONS. 26. RECYCLIZATION OF HETEROARENIUM SALTS BY ACTION OF ACID ANHYDRIDE IN THE PRESENCE OF BASE
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When oxazolium, 1,3,4-thia- and -selenodiazolium, or pyrylium salts react with acid anhydride in the presence of base, they are recyclized to pyrrole, pyrazole, and benzene derivatives, respectively.The typical features of recyclization involving anhydride in a number of five-membered systems are discussed.
- Lipnitskii, V. F.,Shvaika, O. P.
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p. 1398 - 1403
(2007/10/02)
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- Electrochemical Oxidation of 1-Phenylpyrazolidin-3-ones. Part 1. 4- and 5-Substituted 1-Phenylpyrazolidin-3-ones
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The electrochemical oxidation of 4-methyl-, 5-phenyl-, and 4-hydroxymethyl-4-methyl-1-phenylpyrazolidin-3-one in acetonitrile has been studied.All three systems behave in a manner similar to that of the parent 1-phenylpyrazolidin-3-one, the major reaction
- Bellamy, Anthony J.,Innes, David I.,Hillson, Peter J.
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p. 1599 - 1604
(2007/10/02)
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