- Design, synthesis and investigation of new diphenyl substituted pyridazinone derivatives as both cholinesterase and Aβ-aggregation inhibitors
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Background: With respect to the increase in the average life expectancy, Alzheimer Disease (AD), the most common form of age-related dementia, has become a major threat to the population over the age of 65 during the past several decades. The majority of AD treatments are focused on cholinergic and amyloid hypotheses. Objective: In this study, three series of diphenyl-2-(2-(4-substitutedpiperazin-1-yl)ethyl)pyridazin- 3(2H)-one derivatives were designed, synthesized and investigated for their ability to inhibit both cholinesterase enzymes and amyloid-β aggregation. Method: The inhibitory activities of the synthesized compounds on AChE (from electric eel) and BChE (from equine serum) were determined by the modified Ellman’s method. The reported thioflavin T-based fluorometric assay was performed to investigate the effect of the selected compounds on the aggregation of Aβ1-42. The cytotoxic effect of the compounds (4g, 11g and 18g) was monitored in 3T3 cell lines to gain insight into therapeutic potential of the compounds by using MTT assay. The crystal structures of the AChE (1EVE) and BChE (1P0I) enzymes were retrieved from the RCSB Protein Data Bank and Molecular Operating Environment (MOE) software was used for molecular docking of the ligands. Results: Among the tested compounds, 5,6-diphenyl derivative 18g was identified as the most potent and selective AChE inhibitor (IC50 = 1.75 μM, Selectivity Index for AChE > 22.857). 4,6- Diphenyl derivative 11g showed the highest and the most selectivity for BChE (IC50= 4.97 μM, SI for AChE 0.124). Interestingly, 4,5-diphenyl derivative 4g presented dual cholinesterase inhibition (AChE IC50= 5.11 μM; BChE IC50= 14.16 μM, SI for AChE = 2.771). Conclusion: Based on biological activity results and low toxicity of the compounds, it can be said that diphenyl substituted pyridazinone core is a valuable scaffold. Especially, dual inhibitory potencies of 4,5-diphenylpyridazin-3(2H)-one core for the cholinesterase enzymes and Aβ- aggregation makes this core a promising disease-modifying agent.
- Kilic, Burcu,Erdogan, Merve,Gulcan, Hayrettin O.,Aksakal, Fatma,Oruklu, Nihan,Bagriacik, Emin U.,Dogruer, Deniz S.
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- Preparation of β-substituted γ-keto esters by the grignard reaction on N-acylpyrazoles
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Various γ-keto esters were prepared by either the alcoholysis of N-(4-oxoalkanoyl)pyrazoles or the Grignard replacement of pyrazole moiety of 4-(N-pyrazolyl)-4-oxoalkanoic esters. By using 3-phenyl-ι-menthopyrazole as a chiral auxiliary, β-substituted γ-keto esters were enantioselectively obtained.
- Kashima, Choji,Shirahata, Yoshie,Tsukamoto, Yoshihiro
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p. 309 - 317
(2007/10/03)
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- Synthesis of 1,4-Keto Esters and 1,4-Diketones via Palladium-Catalyzed Acylation of Siloxycyclopropanes. Synthetic and Mechanistic Studies
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The reaction of a variety of siloxycyclopropanes with acid chlorides in the presence of a catalytic amount of a palladium/phosphine complex gives 1,4-dicarbonyl compounds to good yield. 1-Alkoxy-1-(trialkylsiloxy)-cyclopropanes react with both aromatic and aliphatic acid chlorides in chloroform to give 1,4-keto esters.Synthesis of 1,4-diketones by the acylation of 1-alkyl- or 1-aryl-1-siloxycyclopropanes has been achieved by carrying out the reaction if HMPA under 10-20 atm of carbon monoxide.Kinetic studies and product analysis revealed the unique mechanism of this reaction, which involves rate-determining cleavage of the strained cyclopropane carbon-carbon bond with a coordinatively unsaturated acylpalladium chloride complex.Ab initio calculations of hydroxylated cyclopropane model compounds showed that the unique reactivities of the siloxycyclopropanes may be correlated with the molecular orbital properties of these compounds rather than their ground-state structural properties.
- Fujimura, Tsutomu,Aoki, Satoshi,Nakamura, Eiichi
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p. 2809 - 2821
(2007/10/02)
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- An Unusual Reaction of a Phosphorane with Benzoins: Formation of 1,2-Dicarbonyl and 1,4-Dicarbonyl Compounds
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Benzoins (1a-e) on reaction with carbethoxymethylenetriphenylphosphorane (2) furnish hydroxy esters (3a-e) and butenolides (4a and 4e) along with the unusual products, benzils (5a-e) and ketoesters (6a-e) as major product.
- Ranade, A. C.,Mali, R. S.,Kurnawal, V. M.
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p. 514 - 517
(2007/10/02)
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- Silyl Phosphites. XVIII. Versatile Utility of α-(Trimethylsilyloxy)-alkylphosphonates as Key Intermediates for Transformation of Aldehydes into Several Carbonyl Derivatives
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Carbonyl addition compounds of diethyl trimethylsilyl phosphite (DTMSP) with aldehydes were converted, by treatment with lithium diisopropylamide (LDA) followed by the successive alkylation and alkaline hydrolysis, to carbonyl derivatives involving aldehydes, unsymmetrical ketones, β,γ-unsaturated ketones, and carboxylic acids. β-Substituted carboxylic esters and γ-substituted lactones were prepared by use of the carbonyl addition compounds of DTMSP with α,β-unsaturated aldehydes.
- Sekine, Mitsuo,Nakajima, Masashi,Kume, Akiko,Hashizume, Akio,Hata, Tsujiaki
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p. 224 - 238
(2007/10/02)
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- Process for preparing ketones
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Ketones are prepared by reacting an aromatic or heterocyclic aldehyde in the presence of a cyanide ion with an unsaturated compound having the formula (I): STR1 wherein R1, R2 and R3 are the same or different and are selected from the group of hydrogen, optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic, heterocyclic and carboxylic acid ester and R4 is nitrile (CN), --CO--R5 or --CO--OR5 wherein R5 is selected from the group of optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic and R1 and R2 and/or R1 and R3 and/or R2 and R5 or R3 and R5 together with the carbon atoms to which they are attached as substituents may also form a carbocyclic or heterocyclic ring. Ketones prepared according to the process of the invention have the formula: STR2 wherein R1 ' and R3 ' are identical or different and are selected from the group of hydrogen, lower alkyl having up to 3 C-atoms and optionally substituted phenyl; and R6 ' is optionally substituted phenyl or a pyridyl.
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