- 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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- PROCESS FOR THE SYNTHESIS OF ARYL HYDRAZINES
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The invention relates to a process for the synthesis of aryl hydrazinesof formula I or a salt thereof, which process comprises subjecting an arene of formula II to a coupling reaction with hydrazine or a derivative thereof, wherein the coupling reaction is conducted in the presence of a catalyst comprising palladium and a diphosphine ligand, wherein the phosphorus atoms are connected through two, three, four, or five atoms selected from car- bon, nitrogen, oxygen or iron, and in which the non-connecting phosphorus substituents are C1- C 10-alkyl or C3-C10-cycloalkyl, wherein the amount of Pd used is up to 0.5 mol-% relative to the amount of arene of formula II; and a base.
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Page/Page column 22; 25; 26
(2020/06/01)
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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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- SPIROINDOLINE ANTIPARASITIC DERIVATIVES
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The invention describes novel spiropiperidines of Formula (1A), (1B), and (1C) stereoisomers thereof, veterinarily acceptable salts thereof, compositions thereof, processes for making, and their use in animals as an antiparasitic. The variables A, R1, R2, R3, R4, v, m, 5, and n are as described herein.
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Page/Page column 106
(2015/07/15)
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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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- Mild and rapid Pd-catalyzed cross-coupling with hydrazine in continuous flow: Application to the synthesis of functionalized heterocycles
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Minimizing risk: The synthesis of arylhydrazines through C?￡?N cross-coupling of aryl chlorides with hydrazine is described. Through the use of continuous flow, the hazards associated with the use of hydrazine in the presence of transition metals are decreased. In addition, multistep flow sequences have also been developed for the generation of functionalized heterocycles utilizing the arylhydrazine intermediates.
- Deangelis, Andrew,Wang, Dong-Hui,Buchwald, Stephen L.
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supporting information
p. 3434 - 3437
(2013/05/09)
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- Use of phenyl hydrazines for seed biostimulation or the treatment of lipoxygenase mediated seed deteriorations
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The present invention provides a method of treating certain deleterious conditions mediated by the action of lipoxygenases in mammals and seeds using certain phenyl hydrazines. Also provided is a method for seed biostimulation using these phenyl hydrazines.
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- Pharmaceutical formulations
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Heterocyclic compounds of formula (I) STR1 and their acid addition salts, when administered topically, exhibit anti-inflammatory activity and do not produce the side-effects associated with the administration of certain other anti-inflammatories. The compounds of formula (I) may be administered topically as the compound alone or in a suitable topical pharmaceutical formulation.
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- Antiimplantation Agents: Part I - 1-Arylthiosemicarbazides
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Several 1-arylthiosemicarbazides, 2-arylhydrazinothiazolines and 2-arylhydrazinodihydrothiazines have been examined for their antiimplantation activity in rats.Among the active compounds, 4-methyl-1-(3,5-bistrifluoromethylphenyl)thiosemicarbazide (3, C 2696-Go) and the corresponding 4,4-dimethyl (47), ethyl (4), n-butyl (5) and allyl (6) derivatives completely inhibit implantation at doses 10, 3, 20, 20 and 30 mg/kg respectively.The 3,4-dichlorophenyl analogue (32) is effective at a dose of 30 mg/kg. 2-(3,5-Bistrifluoromethylphenyl)hydrazinothiazoline (51) and the corresponding dihydrothiazine (63) show a weaker activity.The biological profile of C 2696-Go has been investigated in detail.It appears to prevent implantation by its antiuterotropic activity and ability to inhibit desiduoma formation.
- Nagarajan, K.,Talwalker, P.K.,Kulkarni, C.L.,Venkateswarlu, A.,Prabhu, S.S.,Nayak, G.V.
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p. 1243 - 1257
(2007/10/02)
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- Carbazole methyl malonates
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A process for the preparation of α-methyl-carbazole-2-acetic acids, which comprises reacting an α-methyl-3-oxocyclohexane malonic acid di-lower alkyl ester with a substituted phenylhydrazine, and thereafter sequentially oxidizing and hydrolyzing the reaction product to obtain the desired acid, is described.
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- (Nitrofuryl)pyrazoles, their synthesis and use, and compositions containing them
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3-(5-Nitro-2-furyl)pyrazoles unsubstituted in the 5-position and 5-(5-nitro-2-furyl)pyrazoles unsubstituted in the 3-position are antimicrobials and disinfectants. The compounds are structurally represented by one of the formulae: STR1 wherein A is --CHO, --CN, --COOH, a protected or derived aldehyde group or a protected or derived carboxylic acid group; B is 5-nitro-2-furyl; R1 is --H, substituted or unsubstituted hydrocarbyl (saturated or unsaturated; acyclic, alicyclic or aromatic; or araliphatic); substituted or unsubstituted (cycloaliphatic or aromatic) heterocyclic or acyl (carboxylic or carbonic acid); R2 is --H; and n is a positive whole number of at most 2.
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