- Cross-Coupling between Hydrazine and Aryl Halides with Hydroxide Base at Low Loadings of Palladium by Rate-Determining Deprotonation of Bound Hydrazine
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Reported here is the Pd-catalyzed C–N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as low as 100 ppm of Pd and KOH as base. Mechanistic studies revealed two catalyst resting states: an arylpalladium(II) hydroxide and arylpalladium(II) chloride. These compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matched that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process occurs by rate-limiting deprotonation of a hydrazine-bound arylpalladium(II) chloride complex to give an arylpalladium(II) hydrazido complex.
- Borate, Kailaskumar,Choi, Kyoungmin,Goetz, Roland,Hartwig, John F.,Shinde, Harish,Wang, Justin Y.,Zuend, Stephan J.
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supporting information
p. 399 - 408
(2020/10/29)
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- Deciphering the robustness of pyrazolo-pyridine carboxylate core structure-based compounds for inhibiting α-synuclein in transgenic C. elegans model of Synucleinopathy
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Parkinson's disease (PD), a calamitous neurodegenerative disorder with no cure till date, is closely allied with the misfolding and aggregation of α-Synuclein (α -Syn). Inhibition of α-Syn aggregation is one of the optimistic approaches for the treatment for PD. Here, we carried out hypothesis-driven studies towards synthesising a series of pyrazolo-pyridine carboxylate containing compounds (7a–7m) targeted at reducing deleterious α-Syn aggregation. The target compounds were synthesized through multi-step organic synthesis reactions. From docking studies, compounds 7b, 7g and 7i displayed better interaction with the key residues of α-Syn with values: ?6.8, ?8.9 and ?7.2 Kcal/mol, respectively. In vivo transgenic C. elegans model of Synucleinopathy was used to evaluate the ability of the designed and synthesized compounds to inhibit α-Syn aggregation. These lead compounds 7b, 7g and 7i displayed 1.7, 2.4 and 1.5-fold inhibition of α-Syn with respect to the control. Further, the strategy of employing pyrazolo-pyridine-based compounds worked with success and these scaffolds could be further modified and validated for betterment of endpoints associated with PD.
- Hoda, Nasimul,Maqbool, Mudasir,Rajvansh, Roshani,Srividya, Kottapalli
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- Synthesis, insecticidal activities, and structure-activity relationship of phenylpyrazole derivatives containing a fluoro-substituted benzene moiety
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Fluorinated organic compounds represent a growing and important family of commercial chemicals. Introduction of fluorine into active ingredients has become an effective way to develop modern crop protection products. Given the particular properties of fluorine and high efficiency and selectivity of diamide insecticides, we designed and synthesized 27 anthranilic diamides analogues containing fluoro-sustituted phenylpyrazole. A preliminary bioassay indicated that most target compounds exhibited good biological activity against Mythimna separata and Plutella xylostella. Compound IIIf containing a 2,4,6-trifluoro-substituted benzene ring showed 43% insecticidal activity against M. separata at 0.1 mg L-1, while the control chlorantraniliprole was 36%. The activity of IIIe against P. xylostella at 10-5 mg L-1 was 94%, compared with that of the control being 70%. Thus, introduction of fluorine into diamide insecticides was useful for increasing activity. Insect electrophysiology studies showed that the calcium concentration in the nerve cells of third M. separata larvae was elevated by IIIf, which further confirmed that ryanodine receptor (RyR) was its potential target.
- Gao, Li,Li, Huangong,Li, Yuxin,Li, Zhengming,Ma, Yi,Meng, Fanfei,Sun, Binqiao,Sun, Pengwei,Xie, Yongtao,Xiong, Lixia,Yang, Na,Zhang, Yan,Zhao, Yangyang,Zhou, Sha
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p. 11282 - 11289
(2020/11/09)
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- Preparation method of 2-fluorophenylhydrazine phosphate
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The invention relates to a preparation method of 2-fluorophenylhydrazine phosphate. The preparation method comprises the steps of diazotization, reduction, purification and salification. In the steps of diazotization and reduction, reaction liquid is kept
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Paragraph 0037-0046
(2017/05/18)
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- Preparation method for 2-fluorophenylhydrazine sulfate
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The invention relates to a preparation method for 2-fluorophenylhydrazine sulfate. The preparation method comprises steps of diazotization, reduction, purification, and salt forming. In the steps of diazotization and reduction, concentrated hydrochloric a
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Paragraph 0017 - 0023
(2017/05/20)
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- Preparation method for 2-fluorophenylhydrazine oxalate
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The invention relates to a preparation method for 2-fluorophenylhydrazine oxalate. The preparation method comprises steps of diazotization, reduction, purification, and salt forming. In the steps of diazotization and reduction, concentrated hydrochloric a
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Paragraph 0017; 0018; 0019; 0020-0024; 0027-0034; 0037-0044
(2017/08/28)
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- Synthesis and biological evaluation of benzimidazole phenylhydrazone derivatives as antifungal agents against phytopathogenic fungi
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A series of benzimidazole phenylhydrazone derivatives (6a-6ai) were synthesized and characterized by 1H-NMR, ESI-MS, and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction as (E)-configuration. All the compounds were screened for antifungal activity against Rhizoctonia solani and Magnaporthe oryzae employing a mycelium growth rate method. Compound 6f exhibited significant inhibitory activity against R. solani and M. oryzae with the EC50 values of 1.20 and 1.85 μg/mL, respectively. In vivo testing demonstrated that 6f could effectively control the development of rice sheath blight (RSB) and rice blast (RB) caused by the above two phytopathogens. This work indicated that the compound 6f with a benzimidazole phenylhydrazone scaffold could be considered as a leading structure for the development of novel fungicides.
- Wang, Xing,Chen, Yong-Fei,Yan, Wei,Cao, Ling-Ling,Ye, Yong-Hao
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- Remazol-Catalyzed Hydroperoxyarylation of Styrenes
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A mild photocatalytic hydroperoxyarylation of styrenes has been developed, in which a novel photocatalyst, remazol brilliant blue R (RBBR), is employed at low catalytic loading (1 mol%). The operationally easy procedure uses air as the dioxygen source. Simple mono-substituted styrenes react with aryl hydrazines in moderate-to-good yields. RBBR is proposed to act as a photosensitizer for the generation of singlet oxygen.
- Chen, Ying-Ho,Lee, Ming,Lin, Yi-Zhen,Leow, Dasheng
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supporting information
p. 1618 - 1621
(2015/08/06)
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- Process for preparing arylhydrazines
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The present invention relates to a process for preparing arylhydrazines of the formula R1R2R3Ar-NH-NH2 (I) by reacting an arylhydrazinedisulfonate of the formula in which R1, R2, and R3 are identical or different and are H, C1-C4-alkyl, C1-C4-alkoxy, halogen or OH, Ar is phenyl or naphthyl, M1 and M2 are identical or different and are H, NH4, an alkali metal or +E,fra 1/2+EE alkaline earth metal and R1, R2, R3 and Ar in the formulae (I) and (II) have the same meaning, with water and an inorganic acid at from 0 to 100 DEG C. in the presence of an inert organic solvent to give the corresponding arylhydrazine salt and treating the arylhydrazine salt with a base.
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- Novel chemoselective reduction of aryldiazonium fluoroborates with Zn- NiCl2·6H2O-THF
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Substituted aryldiazonium fluoroborates are selectively reduced to the corresponding phenylhydrazines by using Zn-NiCl2·6H2O in THF as a reducing agent.
- Bandgar,Uppalla
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p. 714 - 715
(2007/10/03)
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- Synthesis and adenosine receptor affinity of a series of pyrazolo[3,4-d]pyrimidine analogues of 1-methylisoguanosine
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Pyrazolo[3,4-d]pyrimidines are pyrazolo analogues of purines. They have been shown to be a general class of compounds which exhibit A1 adenosine receptor affinity. Two series of pyrazolo[3,4-d]pyrimidine analogues of 1-methylisoguanosine have been synthesized. The first involved substitution of the N1-position while the second involved substitution of the N5-position. Both alkyl and aryl substituents were examined. All compounds were tested for A1 adenosine receptor affinity by using a (R)-[3H]-N6-(phenylisopropyl)adenosine binding assay. The 3-chlorophenyl group showed the greatest activity in the N1-position and the butyl group produced the greatest activity in the N5-position. Combination of the best substituent in each of these positions enhanced the overall activity. The most potent compound was 4-amino-5-N-butyl-1-(3-chlorophenyl)-1H-pyrazolo[3,4-d] pyrimidin-6(5H)-one with an IC50 of 6.4 X 10-6 M. Selectivity at the receptor subclasses was examined by performing an A2 adenosine receptor affinity assay with [3H]CGS 21680. This series of compounds were slightly less potent at A2 receptors. 4-Amino-5-N-butyl-1-(3-chlorophenyl)-1H-pyrazolo[3,4-d] pyrimidin-6(5H)-one was the most potent compound with an IC50 of 19.2 X 10-6 M.
- Harden,Quinn,Scammells
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p. 2892 - 2898
(2007/10/02)
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