Derivatives 3a-d Research Articles

New 3-Substituted-2-(4-hydroxyanilino)pyridine Derivatives: Synthesis, Antitumor Activity, and Tubulin Polymerization Inhibition.

A series of new pyridine derivatives 4a-c, 5a-d, 6a-d, 7a-f, and 8a-f structurally related to ABT-751 were synthesized and characterized by spectroscopic means and elemental analysis. All the synthesized compounds were tested for their cytotoxic activity in vitro against the HCT-116 and HepG-2 cancer cell lines using the MTT assay. The results showed that compound 8d has higher cytotoxic activity than the reference antimitotic agent colchicine, against both tested cell lines, with IC50 = 0.52 and 1.40 μM, respectively. The three most active compounds, 5d, 8b, and 8d, were further screened in vitro for inhibition of tubulin and showed remarkable results in comparison to colchicine.

Synthesis of 2,6-Diaryl-4-Indolylpyridines as Novel 5-LOX Inhibitors

A series of 2,6-diaryl substituted -4-indolylpyridines have been synthesized from indole-3-carboxaldehyde and acetophenones and all the compounds characterized by spectroscopic techniques. 5-Lipoxygenase enzyme inhibitory activities were performed for all the compounds. Among the 2, 6-diaryl substituted -4-indolylpyridine derivatives 3ad and 3aa showed good activity.

Investigations on 16-Arylideno Steroids as a New Class of Neuroprotective Agents for the Treatment of Alzheimer's and Parkinson's Diseases.

Neuroinflammatory mechanisms mediated by activated glial and cytokines (TNF-α, IL-1β) might contribute to neuronal degeneration leading to Alzheimer's (AD) and Parkinson's disease (PD). Lipopolysaccharide (LPS) is an inflammogen derived from the cell wall of Gram-negative bacteria, which promotes neuroinflammation and subsequent neurodegeneration. Dehydroepiandrosterone (DHEA) and testosterone have been reported as neuroprotective steroids useful for the treatment of various neurodegenerative disorders. In the present study, several 16-arylidene steroidal derivatives have been evaluated as neuroprotective agents in LPS-treated animal models. It was observed that 16-arylidene steroidal derivatives 1a-d and 6a-h considerably improve LPS-induced learning, memory, and movement deficits in animal models. Biochemical estimations of brain serum of treated animals revealed suppression of oxidative and nitrosative stress, acetylcholinesterase activity, and reduction in TNF-α levels, which were induced through LPS mediated neuroinflammatory mechanisms leading to neurodegeneration of brain. Of all the steroidal derivatives, 16-(4-pyridylidene) steroid 1c and its 4-aza analogue 6c were found to be the most active neuroprotective agents and produced effects comparable to standard drug celecoxib at a much lower dose and better than dexamethasone at the same dose in terms of behavioral, biochemical, and molecular aspects.

Synthesis, spectroscopic analysis and theoretical study of new pyrrole-isoxazoline derivatives

In the present work, we have efficiently synthesized the pyrrole-isoxazoline derivatives (4a-d) by cyclization of substituted 4-chalconylpyrrole (3a-d) with hydroxylamine hydrochloride. The reactivity of substituted 4-chalconylpyrrole (3a-d), towards nucleophiles hydroxylamine hydrochloride was evaluated on the basis of electrophilic reactivity descriptors (fk+, sk+, ωk+) and they were found to be high at unsaturated β carbon of chalconylpyrrole indicating its more proneness to nucleophilic attack and thereby favoring the formation of reported new pyrrole-isoxazoline compounds (4a-d). The structures of newly synthesized pyrrole-isoxazoline derivatives were derived from IR, 1H NMR, Mass, UV–Vis and elemental analysis. All experimental spectral data corroborate well with the calculated spectral data. The FT-IR analysis shows red shifts in vN–H and vC = O stretching due to dimer formation through intermolecular hydrogen bonding. On basis set superposition error correction, the intermolecular interaction energy for (4a-d) is found to be 10.10, 9.99, 10.18, 11.01 and 11.19 kcal/mol respectively. The calculated first hyperpolarizability (β0) values of (4a-d) molecules are in the range of 7.40–9.05 × 10−30 esu indicating their suitability for non–linear optical (NLO) applications. Experimental spectral results, theoretical data, analysis of chalcone intermediates and pyrrole–isoxazolines find usefulness in advancement of pyrrole-azole chemistry.

Synthesis and Some Reactions of 1-aryl-4-acetyl-5-methyl-1,2,3-triazole Derivatives with Anticonvulsant Activity.

The triazoles 3a-d underwent condensation reactions with 4-(piperidin-1-yl)-benzaldehyde to afford the chalcones 5a-d. Chalcone derivatives 5a-d were reacted with 2,3-diaminomaleonitrile, thiourea and hydrazine hydrate to afford the novel diazepine-dicarbonitrile derivatives 7a-d, the pyrimidine-2-thiol derivatives 9a-d and hydrazino-pyrimidines 10a-d respectively. Structures of the prepared compounds were elucidated by physical and spectral data like FT-IR, (1)H NMR, (13)C NMR, and mass spectroscopy. Some of the synthesized compounds were screened for their anticonvulsant activity and SAR.

Synthesis of Hydroxy-Androstane-1,4-Diene-3, 17-Dione Derivatives by Biotransformations of Bile Acids with Pseudomonas alcaliphila

The synthesis of hydroxy-androstane-1,4-diene-3,17-dione derivatives (2a-d) by biotransformations with Pseudomonas alcaliphila of bile acids (1a-d) was reported. The scale-up of addition of deoxycholic acid (1a), cholic acid (1b), and chenodeoxycholic acid (1c) (1 g/L until 10 g/L) to the culture broth of P. alcaliphila switches the degradation process to the synthesis of 12β-hydroxy-androstane-1,4-diene-3,17-dione (2a, 95%), 7α,12β-dihydroxy-androstane- 1,4-diene-3,17-dione (2b, 52%), and 7α-hydroxy-androstane-1,4-diene-3,17-dione (2c, 23%) Also hyodeoxycholic acid (1d) was transformed by P. alcaliphila to 6α-hydroxy-androstane-1,4-diene-3,17-dione (2d) with as much good yields (83%) but with lower concentration (1 g/L) in the culture broth.

An efficient one-pot, three-component synthesis of 6-cyano-hexahydro-4$H$-thieno[3'',2'':5,6]pyrimido[1,2-$a$]quinoline-2-carboxylates and their spiro derivatives from $\beta $-enaminones

A simple and efficient one-pot synthesis of novel thieno[3',2':5,6]pyrimido[1,2-a]quinoline-2-carboxylates (5a-d) and their spirooxindole derivatives (12a-d) was accomplished. Thus, the Michael addition reaction of the cyclic $\beta $-enaminone 3 with the corresponding $\alpha ,\beta $-unsaturated nitrile derivatives 4a-d in refluxing EtOH in the presence of piperidine afforded 5a-d in good yields. On the other hand, spirooxindole derivatives 12a-d were synthesized by the reaction of cyclic $\beta $-enaminone 3 with the corresponding 3-cyanomethylidene-2-oxoindoles 11a-d in refluxing EtOH.

Synthesis and structures of monocyclic 1,4-diaza-2,3-diborine species

New monocyclic 1,4-diaza-2,3-diborine derivatives 3ad, 3ae and 3bc and bicyclic 1,4-diaza-2,3-diborine 8a were prepared by reacting 1,4-diaza-2,3-diene dianion (5) with 1,2-dichlorodiborane (6) and 1,2-dichloro-1,2-diborolane (7). The structures of these new derivatives, which are likely ligands for metal complexes, have been characterized by nuclear magnetic resonance (NMR). The crystal structures of 3ad and 3bc have been determined by single crystal X-ray diffraction technique. In the crystal structure of 3ad, the asymmetric unit contains one-half of the molecule, with the other half generated by (x,y,3/2-z) symmetry operation. Considering the X-ray crystallographic results of these compounds, the B–B bonds are typical for single bonds, with the bond lengths of 1.700 and 1.697Å. Optimized geometric results and Natural Bond Orbital analysis also endorsed that these bond types are single bonds. In 3ad, diazadiborine ring is almost planar, while this ring is in half-chair conformation in 3bc. These compounds, although many aminoboranes are stable in air, were observed not to be stable in air. They have also shown non-aromatic characteristics.

Synthesis and anticancer activity of some new thiopyrano[2,3-d]thiazoles incorporating pyrazole moiety.

The knöevenagel condensation of 3-phenyl-4-thioxo-2-thiazolidinone (1) with 1-phenyl-3-aryl-1H-pyrazole-4-carbaldehydes 2a-d in refluxing glacial acetic acid or in polyethylene glycol-400 (PEG-400) at room temperature without catalyst, afforded the corresponding 5-hetarylmethylene derivatives 3a-d. [4+2]Cycloaddition reaction of compounds 3 with N-arylmaleimides, acrylonitrile and ethyl acrylate afforded thiopyrano[2,3-d]thiazole derivatives 5a-p. The anticancer activity of some of the newly synthesized compounds was investigated against different human cancer cell lines (MCF7 and HEPG2) and confirmed by molecular docking. Moreover, the structure for one representative example of the new products was confirmed by X-ray crystallography. The structure of all the newly synthesized compounds was established by elemental and spectral data.

Imidazoanthraquinone derivatives for the chromofluorogenic sensing of basic anions and trivalent metal cations.

Four imidazoanthraquinone derivatives (2a-d) were synthesized and characterized and their coordination behavior against selected anions and cations tested. Acetonitrile solutions of probes showed charge-transfer absorptions in the 407-465 nm range. The four probes emitted in the 533-571 nm interval. The recognition ability of 2a-d was evaluated in the presence of F(-), Cl(-), Br(-), I(-), OCN(-), BzO(-), ClO4(-), AcO(-), HSO4(-), H2PO4(-), and CN(-). Only F(-), AcO(-), and H2PO4(-) induced a new red-shifted absorption band that was attributed to a deprotonation process involving the amine moiety of the imidazole ring. Moreover, upon increasing quantities of F(-), AcO(-), and H2PO4(-), moderate quenching was induced in the emission of 2a-d together with the appearance of a new red-shifted band. The UV-visible and emission behavior of the four probes in the presence of Cu(2+), Co(2+), Mg(2+), Fe(3+), Ba(2+), Fe(2+), Ni(2+), Ca(2+), Zn(2+), Pb(2+), Cd(2+), Cr(3+), Al(3+), K(+), and Li(+) was also assessed. Only addition of Fe(3+), Cr(3+), and Al(3+) caused a new blue-shifted band in 2a-d that was ascribed to a preferential coordination with the acceptor part of the probes. Moreover, an important quenching of the emission was observed which was ascribed to the interaction between these trivalent cations and 2a-d.

Synthesis and Pharmacological Activities of Some New 2-[1-Heptyl-3-(4- methoxybenzyl)-5-oxo-1,5-dihydro-4H-1,2,4-triazol-4-yl]acetohydrazide Derivatives

Abstract In the present investigation, the key intermediate acetohydrazide derivative 5 was synthesized starting from 3-(4-methoxybenzyl)-4-amino-4,5-dihydro-1,2,4-triazol-5-one (1) by a four-step reaction. Thiosemicarbazides 6a-f and arylidenehydrazide derivatives 8a-d were obtained from compound 5. The cyclization of compounds 6a-f in the presence of NaOH resulted in the formation of compounds 7a-f. The compounds were characterized by IR, 1H NMR, 13C NMR spectroscopy, elemental analysis and mass spectral studies. The compounds were tested for their anti-lipase, anti-α-glucosidase and anti-mycobacterial activities. Compounds 6b and 8c exhibited excellent anti-lipase activity, and compound 8d showed excellent anti-a-glucosidase activity. Compounds 3 and 4 exhibited good antituberculosis activity

Heterocyclic ring extension of androstenedione: Synthesis and cytotoxicity of fused pyran, pyrimidine and thiazole derivatives

The reaction of androstenedione with either malononitrile or ethyl cyanoacetate and aromatic aldehydes 2a-c gave the pyran derivatives 4a-f, respectively. On the other hand, the reaction of androstenedione with thiourea and the aromatic aldehydes 2a-c gave the pyrimidine derivatives 6a-c, respectively. Compound 6b reacted with 2-bromo-1-arylethanone derivatives 7a-d to give the indeno[2,1-e]thiazole derivatives 8a-d. Some of the produced compounds were used for further heterocyclization reactions. The cytotoxicity of the newly obtained products was evaluated against some cancer cell lines and a normal cell line.

Reactivity of Hydrazine, Some Hydrazine derivatives and Diamines toward Ethyl 2,2-Dicyano-1-aryl (or alkyl)vinylcarbamate

A series of pyrimidinone and dipyrimidinone derivatives 2a-c, 4a-e and 6a-f has been synthesized via the reaction between ethyl 2,2-dicyano-1-aryl(or alkyl)vinylcarbamate derivatives 1a-d and hydrazine derivatives or diamines. The reactivity of compounds 1a-d toward hydrazine is studied. The result is the formation of triazolones 5a-d rather than pyrimidinone derivatives.

Synthesis and antimicrobial activity of some amino acids and sulfamoyl and pyrrole derivatives attached to 4-benzoimidazol-2-yl moiety

Background and objectivesBenzoimidazole moiety is one of the heterocyclic compounds that plays a vital role in biological fields such as antioxidant, antidepressant, anticonvulsant, antimicrobial and anticancer. The aim of this study was to construct new compounds containing 4-(5-benzoyl-benzoimidazol-2) moiety incorporated into different amino acids and sulfamoyl and/or pyrrole analogues and to evaluate their antimicrobial activities.Materials and methodsThe starting material 4-(5-benzoyl-1H-benzoimidazol-2-yl)-benzonitrile ( 2 ) was prepared through the reaction of (3,4-diamino-phenyl)-phenyl-methanone ( 1 ) with 4-cyanobenzaldehyde in absolute ethanol. Stirring compound 2 with 70% sulfuric acid gave benzoic acid derivative 3 followed by esterification and refluxing with hydrazine hydrate to form the corresponding 4-(5-benzoyl-1H-benzoimidazol-2-yl)-benzoic acid hydrazide ( 5 ). A series of derivatives 6a-d were prepared by coupling of benzoic acid derivative 3 with different amino acids ethyl ester. Reacting ester compound 4 with different amines and sulfa drugs led to the formation of the amides derivatives 7a,b and 8a,b , whereas on reacting the hydrazide compound 5 with different acid anhydrides, cyclohexane-1,4-dione and 5-nitroisatin compounds 9a-c , 10 and 11 were obtained.Results and conclusionMost of the test compounds were found to be significantly effective against Bacillus subtilis and Staphylococcus aureus (gram-positive bacteria), Escherichia coli and Pseudomonas aeuroginosa (gram-negative bacteria) and Candida albicans and Aspergillus niger (fungi) .

Synthesis, characterization and antibacterial activity of (E)-chalcone derivatives

( E )-Chalcone derivatives were synthesized by the Claisen-Schmidt condensation of aromatic aldehydes with methyl ketones. 5-Arylfuran-2-carboxaldehydes (1a-b) were synthesized by Meerwein´s method and condensed with 2-acetylpyrole or 2-acetylfuran to produce the new chalcone derivatives (2a-d). The new chalcones were characterized using FT-IR and GC-MS. The synthesized compounds were also screened against some bacterial species to evaluate their activity as promising antibacterial agents.

Effect of Substituents on the Structure, Stability, and π-Dimerization of Dithienylpyrrole Radical Cations

A series of 2,5-di(2-thienyl)-N-methylpyrrole derivatives 1a-1d with methylthio end-capping groups and electron-donating substituents at the 3-position of the thiophene rings was synthesized, and the effects of the substituents on the structure, stability, and π-dimerization ability of the radical cation were investigated using UV-vis-NIR and electron spin resonance spectra and density functional theory (DFT) calculations. Among the electron-donating methyl, methoxy, and methylthio substituents, the methoxy derivative 1c gave the most stable radical cation, which persisted in dichloromethane at room temperature under nitrogen for several hours without any apparent decomposition. In addition, 1c(•+) had the largest π-dimerization enthalpy among 1a(•+)-1d(•+). DFT calculations with the M06-2X method revealed that methyl and methylthio derivatives 1b(•+) and 1d(•+) as well as 1c(•+) adopt a cis-cis conformation, in contrast to the trans-trans conformer of unsubstituted 1a(•+), while the π-dimers of all of these compounds were shown to have a cis-cis conformation. On the basis of further detailed analyses, the preformed cis-cis conformation and the weaker intramolecular and intermolecular steric repulsions were considered to explain why 1c(•+) has the largest π-dimerization enthalpy.

Unprecedented Boron-Functionalized Carborane Derivatives by Facile and Selective Cobalt-Induced B–H Activation

The 16-electron complex CpCoS2C2B10H10 (1) is found to react with the alkynes HC≡CC(O)R [R = methyl (Me), phenyl (Ph), styryl (St), ferrocenyl (Fc)] at ambient temperature to give two types of 17-electron cobalt complexes 2a-d and 3a-d containing unique B(3)/B(6)-norbornyl carborane moieties. A formation mechanism via a tandem sequence of metal-induced B-H activation, B-Cp formation, Cp delivery and Diels-Alder addition is proposed on the basis of DFT calculations. The reactivity of these paramagnetic 17-electron complexes has been studied: Exposed to a combination of air, moisture and silica, complexes 2a-d undergo alkyl C-S cleavage to give 16-electron complexes 4a-c containing a boron-norbornadienyl moiety, and simultaneous carboranyl C-S cleavage to afford cobalt-free carborane derivatives 5a-d containing a boron-norbornyl unit. Both 2a-d and 3a-d allow further alkyne insertion into the Co-S bond to generate cobalt-free boron-norbornyl carborane derivatives (Z/E)-7a-d and (Z/E)-8a-d, both containing a vinyl sulfido group. Addition of AlCl3 not only promotes the conversion of 2a-d, but also leads predominantly to (E)-9a-d as retro-Diels-Alder products. Upon heating, the isomerization from E to Z-configuration of the vinyl group and reorganization of the norbornyl moiety of (Z/E)-7a-d occur to lead to (Z)-9a-d as well as the unexpected [1,2]-H shifted products (Z)-10b,c. Thus, the 17-electron complexes 2a-d and 3a-d serve as intermediates for synthesis of variety of boron-functionalized carborane derivatives. In this study, efficient routes have been developed through cobalt-mediated B-H activation to prepare boron-functionalized carborane derivatives that are unavailable by conventional routes.

Synthesis of New Cytotoxic Aminoanthraquinone Derivatives via Nucleophilic Substitution Reactions

Aminoanthraquinones were successfully synthesized via two reaction steps. 1,4-Dihydroxyanthraquinone (1) was first subjected to methylation, reduction and acylation to give an excellent yield of anthracene-1,4-dione (3), 1,4-dimethoxyanthracene-9,10-dione (5) and 9,10-dioxo-9,10-dihydroanthracene-1,4-diyl diacetate (7). Treatment of 1, 3, 5 and 7 with BuNH2 in the presence of PhI(OAc)2 as catalyst produced seven aminoanthraquinone derivatives 1a, b, 3a, and 5a–d. Amination of 3 and 5 afforded three new aminoanthraquinones, namely 2-(butylamino)anthracene-1,4-dione (3a), 2-(butylamino)anthracene-9,10-dione (5a) and 2,3-(dibutylamino)anthracene-9,10-dione (5b). All newly synthesised aminoanthraquinones were examined for their cytotoxic activity against MCF-7 (estrogen receptor positive human breast) and Hep-G2 (human hepatocellular liver carcinoma) cancer cells using MTT assay. Aminoanthraquinones 3a, 5a and 5b exhibited strong cytotoxicity towards both cancer cell lines (IC50 1.1–13.0 µg/mL).

Synthesis, Antifungal and Antitumor Activity of Novel (Z)-5-Hetarylmethylidene-1,3-thiazol-4-ones and (Z)-5-Ethylidene-1,3-thiazol-4-ones

New hetaryl- and alkylidenerhodanine derivatives 3a–d, 3e, and 4a–d were prepared from heterocyclic aldehydes 1a–d or acetaldehyde 1e. The treatment of several rhodanine derivatives 3a–d and 3e with piperidine or morpholine in THF under reflux, afforded (Z)-5-(hetarylmethylidene)-2-(piperidin-1-yl)thiazol-4(5H)-ones and 2-morpholinothiazol-4(5H)-ones 5a–d, 6a–d, and (Z)-5-ethylidene-2-morpholinothiazol-4(5H)-one (5e), respectively, in good yields. Structures of all compounds were determined by IR, 1D and 2D NMR and mass spectrometry. Several of these compounds were screened by the U.S. National Cancer Institute (NCI) to assess their antitumor activity against 60 different human tumor cell lines. Compound 3c showed high activity against HOP-92 (Non-Small Cell Lung Cancer), which was the most sensitive cell line, with GI50 = 0.62 μM and LC50 > 100 μM from the in vitro assays. In vitro antifungal activity of these compounds was also determined against 10 fungal strains. Compound 3e showed activity against all fungal strains tested, but showed high activity against Saccharomyces cerevisiae (MIC 3.9 μg/mL).

Use of transesterified 1,3-diketoesters in the synthesis of trisubstituted pyrazoles and their biological screening

Starting from 2-acetylbenzofuran derivatives 1a-d, methyl/ethyl 4-substituted/unsubstituted benzofuran-2-yl)-2,4-dioxobutanoate 2a-d and 3a-d have been synthesized by Claisen’s condensation reaction with diethyloxalate. The transesterified product, 1,3-diketoester 2a-d on condensation with phenyl hydrazine undergo cyclization to afford the corresponding methyl 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carboxylate 4a-d, which upon further condensation with hydrazine hydrate yielded 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide 5a-d. The structures of the newly synthesized compounds 2a-d, 3a-d, 4a-d and 5a-d were characterized by their elemental analysis and spectral studies such as IR, 1H NMR, 13C NMR and MS. All the synthesized compounds were screened for their antimicrobial activity. Most of the synthesized compounds showed high sensitivity against the selected bacteria and fungi at various concentrations. KEY WORDS: 2,4-Dioxobutanoate, Prazole-3-carboxylate, Pyrazole-3-carbohydrazide Bull. Chem. Soc. Ethiop. 2013, 27(1), 85-94.DOI: http://dx.doi.org/10.4314/bcse.v27i1.9