Synthesis of 5-chloro-3-[4-(3-diethylaminopropoxy)benzoyl]-2-(4-methoxyphenyl)benzofuran as a β-amyloid aggregation Inhibitor

An efficient synthesis of 5-chloro-3-[4-(3-diethylaminopropoxy)benzoyl]-2-(4-methoxyphenyl)benzofuran (8), a potent beta-amyloid aggregation inhibitor, is described. 5-Chloro-2-(4-methoxyphenyl)benzofuran (3) was obtained by the one-pot synthesis of 4-chlorophenol with omega-(methylsulfinyl)-p-methoxyacetophenone (1) under Pummerer reaction conditions, and it was followed by the desulfurization of the resultant 5-chloro-3-methylthio-2-(4-methoxyphenyl)benzofuran (2e). Acylation of benzofuran 3 with 4-(3-bromopropoxy)benzoyl chloride (6) gave the ketone 7, which was converted into compound 8 by the treatment of diethylamine.     

Synthesis and Pharmacokinetics of 2-(4-amino-3,5-dichlorophenyl)-2-(alkylamino)ethanols - Structural Isomers of β2 Agonists Clenproperol and Clenpenterol

Pharmaceutical Chemistry Journal - Methods for the synthesis of 2-(4-amino-3,5-dichlorophenyl)-2-(isopropylamino)ethanol and 2-(4-amino-3,5-dichlorophenyl)-2-(tert-amylamino)ethanol, which are...     

Synthesis of 6-[2-(Benzoxazol-2-ylmethylamino)ethoxy]-1-Alkyl-1H-lndole-2-Carboxylic acid and inhibitory activity on β-Amyloid aggregation

6-[2-(benzoxazol-2-ylmethylamino)ethoxy]-1-alkyl-1H-indole-2-carboxylic acids were designed and synthesized as beta-amyloid (Abeta) fibril assembly inhibitors. Their inhibitory activity on Abeta, aggregation was evaluated by thioflavin T assay although their activities were insignificant.     

Design of β-amyloid aggregation inhibitors from a predicted structural motif

Drug design studies targeting one of the primary toxic agents in Alzheimer's disease, soluble oligomers of amyloid β-protein (Aβ), have been complicated by the rapid, heterogeneous aggregation of Aβ and the resulting difficulty to structurally characterize the peptide. To address this, we have developed [Nle(35), D-Pro(37)]Aβ(42), a substituted peptide inspired from molecular dynamics simulations which forms structures stable enough to be analyzed by NMR. We report herein that [Nle(35), D-Pro(37)]Aβ(42) stabilizes the trimer and prevents mature fibril and β-sheet formation. Further, [Nle(35), D-Pro(37)]Aβ(42) interacts with WT Aβ(42) and reduces aggregation levels and fibril formation in mixtures. Using ligand-based drug design based on [Nle(35), D-Pro(37)]Aβ(42), a lead compound was identified with effects on inhibition similar to the peptide. The ability of [Nle(35), D-Pro(37)]Aβ(42) and the compound to inhibit the aggregation of Aβ(42) provides a novel tool to study the structure of Aβ oligomers. More broadly, our data demonstrate how molecular dynamics simulation can guide experiment for further research into AD.     

Synthesis and evaluation of ¹⁸F-labeled styryltriazole and resveratrol derivatives for β-amyloid plaque imaging

In the present study, a styryltriazole and four resveratrol derivatives were synthesized as candidates for β-amyloid (Aβ) plaque imaging. On the basis of their binding affinities to Aβ(1-42) aggregates, the styryltriazole (1, K(i) = 12.8 nM) and one resveratrol derivative (5, K(i) = 0.49 nM) were labeled with (18)F. In normal mice, tissue distribution of [(18)F]5 showed good initial brain uptake (3.26% ID/g at 2 min) but slow wash-out from brains (2-to-60 min uptake ratio: 2.9). Furthermore, it underwent in vivo metabolic defluorination (1.88% ID/g at 2 min and 9.73% ID/g at 60 min). In contrast, [(18)F]1 displayed high initial brain uptake (5.38% ID/g at 2 min) with rapid wash-out from brains (0.52% ID/g at 60 min; 2-to-60 min uptake ratio: 10.3). These results indicate that [(18)F]1 has in vivo kinetics comparable to PET radiopharmaceuticals currently under commercial development, demonstrating that [(18)F]1 is a desirable PET radioligand for Aβ plaque imaging.     

Construction of a small peptide library related to inhibitor OM99-2 and its structure-activity relationship to β-secretase

AIM: To develop probes for detecting the binding specificity between beta-secretase and substrate, and provide reliable biological activity data for further researching encircling substrate-based inhibitors. METHODS: To prepare the inhibitors, the hydroxyethylene (HE) segment including P1 and P1'was synthesized after multi-step reactions; the combination of all segments was then completed through solid phase synthesis. Recombinant human beta-secretase ectodomain (amino acid residues 1-460) was expressed as a secreted protein with a C-terminal His tag in insect cells using baculovirus infection, and all compounds were evaluated in this beta-secretase enzyme assay. In order to understand the interaction in detail, the theoretical methods, namely molecular dynamics (MD) simulation and molecular mechanics-generalized-born surface area (MM-GBSA) analysis, were performed on the complex of beta-secretase and OM99-2 to obtain the geometrical and energetical information. RESULTS: We designed and constructed a positional scanning combinatorial library including 16 compounds; all members of the library were synthesized based on HE dipeptide isostere. Structure-activity relationship studies at the P4-P1 and P1' -P4'positions led to the discoveries of P and P'sides binding specificity and potent inhibitors 14, 18, and 22. The binding free energy on the whole system and every residue were compared to the biological assay result. CONCLUSION: The removal of P4' yielded inhibitor 22 (A3 *B2) with high potency; further truncation of P3'gave inhibitor 18 (A3 *B1) with equal activity, implying that the right side of the inhibitors play a less important role and could be easily simplified, while change on the P side may cause substantial results.     

Synthesis of β-amino carbonyl derivatives of coumarin and benzofuran and evaluation of their biological activity

A series of β-amino carbonyl compounds containing coumarin (4a–h) and benzofuran (6a–i) moieties was synthesized by a three component Mannich reaction of 3-acetyl-2H-chromen-2-one (1) or 1-(1-benzofuran-2-yl) ethanone (5) with p-substituted aromatic aldehydes (2a–g) and aromatic amines (3a–b) in the presence of cerric ammonium nitrate as a catalyst. The newly synthesized compounds were screened for antimicrobial and antioxidant activities. Compounds 4b, 4e, 4f, 6f, 6g, and 6i showed microbial inhibition with minimal inhibition concentration ranging between 0.040 and 0.500 mg/mL, compounds 4b, 4c, 6c, 6e, and 6i showed promising free radical scavenging activity and compounds 4b, 4f, 6c, 6d, and 6h showed good chelating ability with Fe²⁺ ions. The synthesized compounds were studied for docking on the enzyme, glucosamine-6-phosphate synthase to predict the binding affinity and orientation at the active site of the receptor.     

Synthesis and Anti-inflammatory Activity of 2-(E)-(4-Hy-droxy-3-methoxybenzylidene)-5-(N-Substituted aminomethyl)Cyclopentanones

本文合成了１５种２（Ｅ）（３甲氧基４羟基苯亚甲基）环戊酮杂环胺Ｍａｎｎｉｃｈ碱盐酸盐和芳胺Ｍａｎｎｉｃｈ碱，并进行了初步的抗炎活性筛选。所有化合物结构均经波谱分析和元素分析证实。药理试验结果表明：部分化合物对二甲苯致小鼠耳肿胀有较显著的抑制作用；苯胺取代基的变化对芳胺Ｍａｎｎｉｃｈ碱的抗炎活性有显著的影响。     

Synthesis and structure-affinity relationships of novel dibenzylideneacetone derivatives as probes for β-amyloid plaques

A new and extensive set of dibenzylideneacetone derivatives was synthesized and screened for affinity toward Aβ(1-42) aggregates. Structure-activity relationships revealed the binding of dibenzylideneacetones to be affected by various substituents. The introduction of a substituent group in the ortho position reduced or abolished the binding. However, the para position was highly tolerant of sterically demanding substitutions. Three radioiodinated ligands (6, 70, and 71) and two (18)F fluoro-pegylated (FPEG) ligands (83 and 85) were prepared, all of which displayed high affinity for Aβ(1-42) aggregates (K(i) ranging from 0.9 to 7.0 nM). In biodistribution experiments, they exhibited good initial penetration (1.59, 4.68, 4.56, 4.13, and 5.15% ID/g, respectively, at 2 min) of and fast clearance from the brain. Autoradiography with sections of postmortem AD brain and transgenic mouse brain confirmed the high affinity of these tracers. These preliminary results strongly suggest the dibenzylideneacetone structure to be a potential new scaffold for β-amyloid imaging probes.     

Synthesis and anticonvulsant evaluation of A series of (R)- and (S)-N-Cbz-α-aminosuccinmide and their structure activity relationship

A series ofN-Cbz-α-aminosucinimides (1), combining common moieties of various anticonvulsants such as N-CO-C-N and cyclic imide in a single molecule, were synthesized from the corresponding (R)- and (S)-N-Cbz-aspartic acid (2). And theirin vivo anticonvulsant evaluations in MES and PTZ test were investigated. And also the rotorod test for neurotoxicity was investigated. All the tested compounds (1), except1c and1f, showed significant anticonvulsant activities in both MES and PTZ test. And the most active compound among them in MES test was (R)-N-Cbz-α-amino-N-methylsuccinimide (1b) (ED₅₀=52.5 mg/kg) and (S)-N-Cbz-aminosuccinimide((1d) was most active in PTZ test (ED₅₀=78.1 mg/kg). And the TD₅₀ values of the tested compounds were above 117.5 mg/kg. These pharmacological data were comparable to those of currently available anticonvulsants. And also we found that the pharmacological effects were dependent on theirN-substituted alkyl chains and their stereochemistry.     

Synthesis and Biological Activities of Some Mannich Bases of 5-(4-Hydroxyphenyl)-1,3,4-Oxadiazole-2-Thione

以对羟基苯甲酸乙酯为原料，经肼解、环化合成５（４羟基苯基）１，３，４二唑２硫酮，继而经Ｍａｎｎｉｃｈ反应合成了四种新曼尼希碱，其结构经红外光谱、核磁共振和元素分析证实。初步抑菌活性试验表明，显示弱的抑菌活性。     

Synthesis and binding affinities of 5-(3-pyridinyl)- and 5-(3-quinolinyl)-4-azahomoadamantanes to α7 nicotinic acetylcholine receptors

A general synthetic route that can lead to nicotinic ligands bearing a variety of bulky aza-ring systems was developed. This methodology was applied to obtain 5-(3-pyridinyl)- and 5-(3-quinolinyl)-4-azahomoadamantanes 2a, 3a and 2b, 3b. The parent 5-(3-pyridinyl)-4-azahomoadamantane 2a (Ki=5.0 μM) binds with about 100 times lower affinity than (+)−epibatidine 1 (Ki=0.045 μM) to α7 nicotinic acetylcholine receptors (nAChRs). N-methyl substitution of 2a gives compound 3a which has about nine times lower binding affinity. The replacement of pyridinyl with a quinolinyl ring (compounds 2b, 3b) results in a dramatic reduction in potency (Ki>1000 μM).     

Synthesis and β-Adrenergic Activities of R-Fluoronaphthyloxypropanolamine

Purpose. Many biogenic amines where an aromatic proton is substituted with fluorine have exhibited pharmacological properties that are dependent on the position of fluorine on the aromatic ring. For example, 6-fluoroepinephrine is selective for -adrenergic receptors whereas the 2-fluoroisomer is selective for -receptors. Aryloxypropanolamines are -receptor agonists or antagonists, depending on the aryl group and its substituents. We therefore hypothesized that fluorine substitution on the aromatic ring could lead to significant biological effects in this class. A target with fluorine on naphthyl group of a known -antagonist was chosen for investigation. Methods. Synthesis of the target compound began with fluoronaphthalene and involved introduction of 4-hydroxy group by Friedel-Crafts acylation followed by Baeyer Villiger oxidation. The side chain was introduced stereoselectively using the chiral synthon (2R)-glycidyl 3-nitrobenzenesulfonate, a Sharpless epoxidation technique. The epoxide was opened with t-butyl amine. HPLC methods were used to characterize %ee of the enantiomer. Results. The target compound was synthesized in several hundred milligram quantity, and in good yield and high enantiomeric excess, showing practicality of the synthetic scheme. It exhibited potent binding activities on -adrenergic receptors, and was found to be two times selective for ₂-receptors over ₁. Conclusions. The current report demonstrates that aromatic fluorine substitution on -adrenergic ligands can be achieved, and that such can be used to obtain binding selectivity between receptors.     

Synthesis and Antiarrhythmic Activity of N-[2-(Adamantan-2-YL)Aminocarbonyl-Methyl-N′-(Dialkylamino)Alkylnitrobenzamides

Pharmaceutical Chemistry Journal - Novel 2-aminoadamantane derivatives, specifically N-[2-(adamant-2-yl)-aminocarbonylmethyl]-N′-(dialkylamino) alkylnitrobenzamides and their physiologically...     

Synthesis of 6-[1-[4-(benzoxazol-2-yl)thiobuthyl]-1,2,3-triazole-4-yl]methylenepenam as β-lactamase inhibitors

The 6,6-dibromopenam6 was treated with CH₃MgBr and carbaldehyde5 to afford the 6-bromo-6-(1-hydroxy-1-methyl)penicillanate7, which was reacted with acetic anhydride to give acetoxy compound8. The deacetobromination of8 with zinc and acetic acid gave 6-exomethylenpenams, Z-isomer9 and E-isomer10, which were oxidized to sulfones11 and12 by m-CPBA. The p-methoxybenzyl compounds were deprotected by AlCl₃ and neutralized to give the sodium salts13, 14, and15.     

Synthesis of 3-(5-bromo-2,3-dimethoxy-phenyl)-[1, 2, 4] oxadiazole analogues and their evaluation as anti-Parkinson′s agents

A series of 3-(5-bromo-2,3-dimethoxy-phenyl)-[1, 2, 4] oxadiazole derivatives was prepared and their evaluation for anti-Parkinson’s activity was measured in vivo using albino rats. The result of the biological activity studies indicated that some of the synthesized compounds have good agonistic activity on the dopamine receptors and a few of them were also found to be free from neurotoxicity. Thus these compounds might be useful ligands for studying the functional role of dopamine receptors in vivo. The high log P value of the compounds indicates that they should easily cross the blood-brain barrier (log P > 2.6).      

Synthesis and antibacterial evaluation of Cu(II) and Zn(II) complexes of the β-lactum antibiotic, cefdinir

In this study, the coordination chemistry of the antibiotic, cefdinir, and its metal complexes with Cu (II) and Zn (II) was described and characterized on the basis of analytical and spectral studies. The synthesized complexes were evaluated in vitro for their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli. The metal complexes possessed the better antibacterial activity against the selected species of bacteria than the free antibiotic (cefdinir). The results were supported by the increase in log P values of metal complexes in comparison to the free ligand cefdinir. The importance of these findings lies in the fact that these complexes could be applied in the treatment of common bacterial infections.     

Comparison of dynamics of extracellular accesses to the β(1) and β(2) adrenoceptors binding sites uncovers the potential of kinetic basis of antagonist selectivity

From the molecular mechanism of antagonist unbinding in the β(1) and β(2) adrenoceptors investigated by steered molecular dynamics, we attempt to provide further possibilities of ligand subtype and subspecies selectivity. We have simulated unbinding of β(1)-selective Esmolol and β(2)-selective ICI-118551 from both receptors to the extracellular environment and found distinct molecular features of unbinding. By calculating work profiles, we show different preference in antagonist unbinding pathways between the receptors, in particular, perpendicular to the membrane pathway is favourable in the β(1) adrenoceptor, whereas the lateral pathway involving helices 5, 6 and 7 is preferable in the β(2) adrenoceptor. The estimated free energy change of unbinding based on the preferable pathway correlates with the experimental ligand selectivity. We then show that the non-conserved K347 (6.58) appears to facilitate in guiding Esmolol to the extracellular surface via hydrogen bonds in the β(1) adrenoceptor. In contrast, hydrophobic and aromatic interactions dominate in driving ICI-118551 through the easiest pathway in the β(2) adrenoceptor. We show how our study can stimulate design of selective antagonists and discuss other possible molecular reasons of ligand selectivity, involving sequential binding of agonists and glycosylation of the receptor extracellular surface.     

Different steric characteristics of β1- and β2-adrenoceptors

Summary -Adrenoceptors of lung (75% ₂) and heart (95% ₁) of calf were labelled with ³H-(–)-propranolol. The stereoisomers of 10 ligands were used to inhibit the binding of ³H-(–)-propranolol to membrane particles. The affinity ratio of sereoisomers is consistently greater for ₁-adrenoceptors than for ₂-adrenoceptors, regardless of whether the ligands are agonists, partial agonists or antagonists. The ₁-adrenoceptor appears to possess stricter steric requirements than the ₂-adrenoceptor. This property may prove helpful in differentiating the -adrenoceptor subtypes during receptor solubilization and purification.