X-ray structural analysis and antitumor activity of new salicylic acid derivatives

Tetrakis-, tris-, bis-, and mono salicylic acid derivatives 1–4 were synthesized by reaction of methyl 2-hydroxy benzoate (methyl salicylate) with 2,2-bis (hydroxymethyl) propane-1,3-diol (pentaerythritol) in the presence of sodium. Yields of different salicyloyloxy derivatives were changed by varying the molar ratios of reactants. For compounds 2 and 3, X-ray structure analysis was performed, as well as molecular energy minimization, to define their conformation in terms of their energy minima. Comparison of crystal and energy minimized structures for these two compounds (2 and 3) revealed that the intramolecular hydrogen bonds play an important role, stabilizing conformation of the most part of the molecule. The antioxidant activity and cytotoxicity of the synthesized derivatives were evaluated in a series of in vitro tests, as well as 17β-hydroxysteroid dehydrogenase type 2 inhibition potency. Tetrakis salicyloyloxy derivative 1 expressed the highest antioxidant potency, tris salicyloyloxy derivative 2 was the best inhibitor of 17βHSD2 enzyme, while bis salicyloyloxy derivative 3 showed strong cytotoxicity against prostate and breast cancer cells with no cytotoxicity against healthy cells.     

Cytotoxicity, antioxidant, and antimicrobial activities of novel 2-quinolone derivatives derived from coumarin

Coumarins are important and useful compounds with diverse pharmacological properties. New coumarin derivatives namely N-aminoquinoline-2-one 1, 1-((4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)methyleneamino)quinolin-2(1H)-one 2 and 1,1′-(1E,1′E)-(1,4-phenylenebis(methan-1-yl-1-ylidene))bis(azan-1-yl-1-ylidene)diquinolin-2(1H)-one 3, were synthesized and characterized by UV–Vis, FT-IR, and NMR spectra in addition of elemental analysis. The synthesized compounds (2 and 3) show considerable anticancer activity against HEp-2 cell line. Synthesized compounds (2 and 3) were tested against selected types of microbial organisms and showed significant activities. The free-radical scavenging activity of synthesized compounds (2 and 3) have been determined by their interaction with the stable free-radical 1,1-diphenyl-2-picrilhydrazyl (DPPH) and all the compounds have shown encouraging antioxidant activities.     

Syntheses,structures, magnetic properties,and photoluminescence of compounds Ln(2,2′-Bipy)(C4H8NCS2)3 · 0.5CH2Cl2 (Ln = Sm,Eu, Tb,Dy, and Tm)

Five compounds of the composition Ln(2,2′-Bipy)(C₄H₈NCS₂)₃ · 0.5CH₂Cl₂ (Ln = Sm (I), Eu (II), Tb (III), Dy (IV), and Tm (V); 2,2′-Bipy = 2,2′-bipyridine) are synthesized. According to the X-ray diffraction data (CIF file CCDC 986259), the crystal structure of compound I consists of molecules of the mononuclear complex [Sm(2,2′-Bipy)(C₄H₈NCS₂)₃] and solvate molecules CH₂Cl₂ (2 : 1). The coordination polyhedron N₂S₆ of the Sm atom is a distorted tetragonal antiprism. The X-ray diffraction analysis shows that compounds I–V are isostructural. The magnetic properties of compounds I–V are analyzed in the temperature range from 2 to 300 K. At 300 K compounds I and III are photoluminescent in the visible spectral range. The photoluminescence intensity of compound I considerably exceeds that of complex III.     

Characterization of pure phase Zn(II) oxide nanoparticles via thermal decomposition of two zinc(II) complexes of the 6,6′-dimethyl-2,2′-bipyridine ligand

Two zinc(II) complexes [Zn(6,6′-dimethyl-2,2′-bipy)Cl₂] _n (1) and [Zn(6,6′-dimethyl-2,2′-bipy)I₂] _n (2) are synthesized from the reaction of the 6,6′-dimethyl-2,2′-bipy ligand with ZnCl₂ and ZnI₂. Zinc(II) oxide nanoparticles are synthesized by the thermolysis of [Zn(6,6′-dimethyl-2,2′-bipy)Cl₂] _n (1) and [Zn(6,6′-dimethyl-2,2′-bipy)I₂] _n (2) at two different temperatures. The ZnO nanoparticles are characterized by X-ray diffraction and scanning electron microscopy (SEM). SEM images show the average size of the ZnO nanoparticles produced of 50 nm and 60 nm in compounds 1 and 2 respectively.     

Synthesis and photophysical properties of 2,2′-binaphthalene-based receptor bearing trimethylsilyl groups to improve the solubility

Two trimethylsilyl groups were introduced at 5- and 5′-positions of 2,2′-binaphthalene to improve the solubility of 2,2′-binaphthalene-based receptors. The X-ray crystallographic analysis revealed the twisted structure of 2 in the solid state. The solubility of 2 was moderately improved by 3.1-fold comparing with mother skeleton 1. As a practical example of 2, receptor 8 bearing two aza-15-crown-5 moieties was prepared and the selective binding of 8 with Ba²⁺ can be observed by the formation of sandwich-like complex, which shows no prevention of binding ability of the receptor by introduction of the bulky substituents.     

Synthesis,structure, and properties of trinuclear pivalate {Zn2Eu} complexes with N-donor ligands

New luminescent heterometallic complexes of Eu³⁺ and Zn²⁺ were synthesized: Zn₂Eu(NO₃)(Piv)₆(L)₂ (Piv is pivalate anion, L = MeCN (1), 2,3-lutidine (2), 2,2′-bpy (3)) and [Zn₂(Piv)₃(2,2′-bpy)₂][ZnEu(NO₃)₃(Piv)₃(2,2′-bpy)] (4). In the case of 2,2′-bpy, the order of mixing of the reagents ([Zn(Piv)₂] _n , Eu(NO₃)₃·6H₂O, and 2,2′-bpy) affects the composition of the final reaction product: the reaction of [Zn(Piv)₂] _n and Eu(NO₃)₃·6H₂O (in the ratio Zn : Eu = 3 : 1) in MeCN affords complex 1 and the subsequent addition of 2,2′-bpy (Zn : L = 1 : 1) affords complex 3. Complex 4 is formed in the reaction of [Zn(Piv)₂] _n and 2,2′-bpy (Zn : L = 1 : 1) in MeCN followed by the addition of Eu(NO₃)₃·6H₂O (Zn : Eu = 3 : 1). The luminescence spectra of compounds 1–4 (Zn : Eu = 3 : 1) exhibit metal-centered luminescence of Eu³⁺. The most efficient ligand-antenna is 2,2′-bpy, which is due to the optimum position of the triplet level of this ligand.     

Benzoylacetonate and its fluorinated derivatives as ligands for Co(II) complexes: the effect of the presence of fluorine atoms on the crystal packing

The influence of the introduced fluorine atoms to diketonato backbone exerted on the crystal packing was studied on cobalt(II) bis(4,4,4-trifluoro-1-phenylbutane-1,3-dionato-κ ² O,O′) compounds with pyridine (1), 2,2′-bipyridine (2) and 1,10-phenanthroline (4), and cobalt(II) bis(benzoylacetonato-κ ² O,O′) compound with 2,2′-bipyridine (3). The solid-state structures of 1–4 were determined by single crystal X-ray analysis. The coordination of Co(II) is octahedral in all four compounds. The differences in crystal packing of 1 with regard to the known complexes with non-fluorinated analogue and 4,4,4-trifluoro-1-(4-fluorophenyl)butane-1,3-dionate were observed. Unit cell parameters of 2·½C₇H₈ and 3·½C₇H₈ slightly differ, but they have similar crystal packing dominated by the π–π interactions. Strong π–π interactions and weak C–H···π(arene) and C–F···π(arene) interactions are present in 2–4, while no significant intermolecular interactions are present in 1.     

Reaktion der Tautomeren 4-Hydroxy-2H-thiopyran-2-thion und 2-Mercapto-4H-thiopyran-4-on mit aliphatischen Aldehyden

5,6-Dihydro-4-hydroxy-6,6-dimethyl-2H-thiopyrane-2-thione (1 I) and its tautomer 2-mercapto-4H-thiopyrane-4-one (1 II) react with aliphatic aldehydes under different reaction conditions to yield mainly 5R-7,8-dihydro-2H,5H,6H-thiopyrano[2,3—b:6,5—b′]-bisthiopyran-4,6(3H)-diones2 and 2′R,4′R-5,6,6′,7′-tetrahydro-2-thioxo-spiro(4H-thiopyran-3(2H), 3′(4′H)-2′H,5′H-thiopyrano-[2,3—b]-thiopyran)-4,5′-diones3. The mechanisms of formation of the condensates2 and3 and their stereochemistry are discussed. The reaction yielding2 is analogous to the condensation of dimedone with subsequent anhydride formation.3 might be generated byDiels-Adler reaction of intermediately formed 2-thioxo-3-alkylidenethiopyranones4. An X-ray crystal structure analysis was carried out on3 b to establish its configuration and conformation.     

Mixed-ligand oxovanadium complexes incorporating Schiff base ligands: synthesis, DNA interactions, and cytotoxicities

Three oxovanadium complexes, namely [VO(NOSAA)(bpy)] (1) (NOSAA = 2-hydroxy-5-nitrosalicylidene anthranilic acid, bpy = 2,2′-bipyridyl), [VO(NOSAA)(4,4′-dimebpy)] (2) (4,4′-dimebpy = 4,4′-dimethyl-2,2′- bipyridyl), and [VO(NOSAA)(phen)] (3) (phen = 1,10-phenanthroline), have been prepared and characterized. The binding modes and strengths of these complexes with calf thymus DNA (CT-DNA) were studied using various techniques. The chemical nuclease activities and photocleavage reactions of the complexes were also tested. All three complexes interact with CT-DNA through intercalative modes, and complex 3 possesses the largest binding affinity. All three complexes can efficiently cleave pBR322 DNA upon irradiation or under physiological conditions in the presence of H₂O₂, and complex 3 has the best cleaving ability. In vitro experimental results showed that the three complexes are cytotoxic against myeloma (Ag8.653) and gliomas (U251) cell lines and complex 3 again showed the highest efficacy.     

Syntheses, spectroscopic characterization and metal ion binding properties of benzo-15-crown-5 derivatives and their sodium and nickel(II) complexes

New benzo-15-crown-5 derivatives containing nitro, amine and imine groups were prepared. Nitro compound (1) was prepared after the reaction?4′,5′-bis(bromethyl)benzo-15-crown-5 and o-nitrophenol in the presence of NaOH. After reduction process by using hydrazine hydrate and Pd/C amine compound (2) was formed. New crown ether imine compounds (3–5) were synthesized by the condensation of corresponding crown ether diamine (2) with salicylaldehyde derivatives. Sodium complexes of the crown compounds (1a–5a) form crystalline 1:1 (Na⁺: ligand) complexes with sodium perchlorate. Nickel(II) complexes (3b–5b) with 1:1 (Ni²⁺:ligand) stoichiometries were also been synthesized from the Schiff bases (3–5). The results indicated that the Schiff base ligands coordinated through the azomethine nitrogen and phenolic oxygen. The extraction ability of compounds (1, 3, 4 and 5) were also evaluated in chloroform by using several alkali and transition metal picrates such as Li⁺, Na⁺, K⁺, Cr³⁺, Mn²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Pb²⁺.     

Synthesis and characterization of benzothiazol-2-one derivatives as anti-inflammatory and analgesic agents

A series of new compounds bearing a 1,3-benzothiazol-2-one nucleus have been synthesized using 5,6-dimethyl-3-(2-oxo-propyl)-1,3-benzothiazol-2-one (1) as a key starting compound. The reaction of 1 with some nucleophilic compounds led to the formation of compounds 2, 3, 4, 5a, b, 6 and 7a, b. The thiosemicarbazone derivatives 7a, b were treated with a number of halo ketones to produce the new heterocyclic compounds 9–13, while their reaction with acid anhydrides led to the formation of the derivatives 14 and 15. Also, compound 1 was condensed with different aromatic aldehydes to afford the corresponding chalcones 18–22. The structures of all the novel compounds have been determined by analytical and spectral data. Some of the compounds were selected to be evaluated as anti-inflammatory and analgesic agents.     

Ultrasonic assistance syntheses of new nano-sized lead(II) coordination polymers: motifs for PbO preparation

Nanoparticles of two new coordination polymers, [Pb(5,5′-dm-2,2′-bpy)Cl₂] _n (1) and [Pb(5,5′-dm-2,2′-bpy)Br₂] _n (2), {5,5′-dm-2,2′-bpy = 5,5′-dimethyl-2,2′-bipyridine}, have been synthesized by ultrasonic assistance at different concentrations and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. Metal oxide nanoparticles were prepared from thermal decomposition of compounds 1 and 2 at 600 °C under air atmosphere. Scanning electron microscopy images of the residue which are obtained from calcination of compounds 1, 2 show the formation of lead(II) oxide nanoparticles with an average diameter of about 80 and 90 nm for compounds 1 and 2, respectively.     

Synthesis and photoluminescence of complexes Tm(L)(iso-Bu2PS2)2(NO3) (L = Phen, 2,2′-Bipy). Crystal structures of compounds [Ln(2,2′-Bipy)(iso-Bu2PS2)2(NO3)] · C6H6 (Ln = Tm, Tb)

Heteroligand complexes Tm(L)(iso-Bu₂PS₂)₂(NO₃) (L = 2,2′-Bipy (II), Phen (III)) are synthesized. According to the X-ray phase analysis data, complex III is isostructural to mononuclear compound [Dy(Phen)(iso-Bu₂PS₂)₂(NO₃)] including, according to the X-ray diffraction data, a coordination polyhedron DyN₂O₂S₄ (distorted dodecahedron). Single crystals of compounds [Ln(2,2′-Bipy)(iso-Bu₂PS₂)₂(NO₃)] · C₆H₆ (Ln = Tm (IV), Tb (V)) are obtained. An X-ray diffraction analysis shows that the crystal structures of these isostructural compounds are formed by molecules of mononuclear complexes [Ln(2,2′-Bipy)(iso-Bu₂PS₂)₂(NO₃) and uncoordinated C₆H₆ molecules. In complexes IV and V, the ligands [Ln(2,2′-Bipy)(iso-Bu₂PS ₂ ^? , and NO ₃ ^? are bidentate-cyclic. The coordination polyhedron LnN₂O₂S₄ is a distorted dodecahedron. Complexes II and III possess photoluminescence in the visible spectral range (λ_max = 478 and 477 nm, respectively).     

Investigating the potential of tetrahydropyridinyl chalcones as useful agents against breast carcinoma: An in vitro and in vivo study

N-Benzyltetrahydropyridinyl-4,6-dimethoxy phenyl-substituted 2′-hydroxychalcones SJC1–15 were synthesized using Claisen–Schmidt condensation, their structures confirmed by spectral analysis, and their anticancer activity evaluated. To support their biological activity, physicochemical parameters such as lipophilicity and oxidation potential were determined. To assess their relative cytotoxicity, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed using MCF-7, T-47D, MDA MB-231, HepG₂, and Vero cell lines. The cytotoxicity of the chalcones was found to vary with the nature of the ring B substituents. The lipophilicity of the cytotoxic compounds expressed in terms of distribution coefficient was found to lie in the range of 2.4–4.2. Further evaluation of their antioxidant potential revealed antioxidant activity by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assay and irreversible electrochemical reaction with oxidation potential in the range of 0.879–1.048 V. Of the 15 chalcones, SJC4, 5, 9 were selected for further in vitro studies using MCF-7. The compounds exhibited significant apoptotic effect and caused cell cycle arrest at G0/G1 and G2/M phase. Among them, two of the O-alkylated chalcones (SJC5, 9) showing promising activity against hormone-responsive breast cancer cells were evaluated for their in vivo anticancer activity using 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumor model. Three-week treatment with the test compounds at oral dosage of 100 mg kg^?1 per day significantly improved elevated tumor parameters compared with tumor control. Treatment with chalcone SJC5 (a 2,4,5-trimethoxy derivative) exhibited anticancer effects similar to those of doxorubicin (2 mg kg^?1 per week, i.p.) and was free from toxic effects observed with doxorubicin treatment.     

Photocatalytic reduction of CO2 using cis,trans-[Re(dmbpy)(CO)2(PR3)(PR’3)]+ (dmbpy=4,4′-dimethyl-2,2′-bipyridine)

Photocatalysis of biscarbonylrhenium complexes cis,trans-[Re(dmbpy)(CO)₂(PR₃) (PR′₃)]⁺ (dmbpy=4,4′-dimethyl-2,2′-bipyridine: R, R′=Ph (1a ⁺); p-FPh (1b ⁺); R=Ph, R′=OEt (1c ⁺); R, R′=O-i-Pr (1d ⁺)) is reported for the first time. The rhenium complexes with two triarylphosphine ligands (1a ⁺, 1b ⁺) efficiently photocatalyzed CO₂ reduction with triethanolamine as a sacrificial donor. On the other hand, the complexes with one or two trialkylphosphite ligand(s) (1c ⁺, 1d ⁺) had low photocatalytic abilities under the same reaction conditions.     

Synthesis and crystal structures of the Zn(II) and Co(II) complexes containing the reduced derivative nitronyl nitroxide

Two complexes of formulas [Zn(Hfac)₂(IM-IMH-Bph)] (I) and [Co(Hfac)₃](IM-Bph) (II), where IM-Bph = 2,2′-bis(1′-oxyl-4′,4′,5′,5′-tetramethylimidazoline-2′-yl)-bis(2-formylphenyl) ether; Hfac = hexafluoroacetylacetonate, have been synthesized and characterized by single-crystal X-ray diffraction. The X-ray analysis demonstrates that both I and II are mononuclear complexes. In I, each zinc ion is five-coordinated with four oxygen atoms from two Hfac ligands and one oxygen atom from nitroxide. Complex II contains one Co(III) atom with six oxygen atoms from three Hfac ligands and uncoordinated IM-Bph diradical, in which the Co²⁺ ion and NIT-Bph biradical can undergo the redox reaction.     

Synthesis and anti-viral activities of some 3-(naphthalen-1-ylmethylene)-5-phenylfuran-2(3H)-one candidates

3-(Naphthalen-1-ylmethylene)-5-phenylfuran-2(3H)-one 1 was prepared and converted into a variety of heterocyclic systems of synthetic and biological importance. Benzylamine was reacted with furanone 1 to afford compounds 2 and 3 according to the reaction conditions. Butanamide 2 was reacted with thionyl chloride or thiourea to give derivatives 4 and 5, respectively. Compound 3 was reacted with ethyl cyanoacetate to give the corresponding pyrrolopyridine derivative 6. Treatment of 1 with hydrazine hydrate afforded compounds 7 and 8 according to the reaction conditions. Also, compound 1 was reacted with phenyl hydrazine, hydroxyl amine, malononitrile or thiourea to give compounds 9–12, respectively. Cyclization of 7 with ethoxymethylene-malononitrile, ethyl-(ethoxymethylene)cyanoacetate, carbon disulphide or acetylacetone afforded the corresponding compounds 13–16, respectively. Condensation of 7 with p-nitrobenzaldehyde gave the corresponding hydrazone 17, which was treated with thioglycolic acid or chloroacetyl chloride to give compounds 18 and 19, respectively. Also, most of the prepared products were tested for anti-avian influenza virus and revealed promising antiviral activity against H5N1 virus [A/Chicken/Egypt/1/2006 (H5N1)] by determination of both TC ₅₀ and ED ₅₀ and confirmed by plaque reduction assay on MDCK cells. Compounds 7, 8, 11, 12 and 13 showed the highest effect compared with the other tested compounds.     

The unimolecular thermal decomposition of oxetane and its methyl derivatives: An Ab initio and RRKM calculations

Quantum mechanical and Rice-Ramsperger-Kassel-Marcus (RRKM) calculations are carried out to study the thermal unimolecular decomposition of oxetane (1), 2-methyloxetane (2), and 2,2-dimethyloxetane (3) at the MPW1PW91/6-311 + G** level of theory. The results of the calculations reveal that decomposition reaction of compounds 1?C3 yields formaldehyde and the corresponding substituted olefin. The predicted high-pressure-limit rate constants for the decomposition compounds 1?C3 are represented as 6.61 × 10¹³exp(?32472/T), 9.33 × 10¹³exp(?29873/T), and 4.79 × 10¹³exp(?27055/T) s^?1, respectively. The fall-off pressures for the decomposition of compounds 1?C3 are found to be 9.42 × 10^?2, 3.67 × 10^?3, and 7.26 × 10^?4 mm Hg, respectively. As the fall-off pressure of the decomposition process of compounds 1?C3 are in the following order: P _1/2(1) > P _1/2(2) > P _1/2(3); therefore the decomposition rates are as follow: rate(1) < rate(2) < (3).     

Synthesis, X-ray structural analysis, and cytotoxic activity of some new androstane d-homo lactone derivatives

A series of d-homo lactones 4?C10 from dehydroepiandrosterone 1 via 16-hydroximino derivatives 2 and 3 were synthesized. The d-homo lactone 4 was transformed by the Oppenauer oxidation to obtain compound 5. The (Z)-2-hydroxymethylene-4-en-3-one compound 6, was obtained through reaction of 4-en-3-one compound 5 with ethyl formate and sodium hydride. The epoxides 8 and 9 were prepared from compound 7 by oxidation with m-chloroperbenzoic acid. Compound 10 was obtained by treating epoxides 8 and 9 with chromium(VI)-oxide. The structure of compounds 6 and 10 were confirmed by X-ray structural analysis. These derivatives were screened for antitumor activity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER?, MDA-MB-231, prostate cancer AR?, PC-3), and one human non-tumor cell line, MRC-5. Compounds 4, 7, 8, and 10 exhibited significant antitumor activity against MDA-MB-231 cells, while compound 5 showed strong cytotoxicity against MDA-MB-231. No compounds displayed toxicity against MRC-5 cells.     

Über substituierte 1,6-Dihydro-1,3,5-triazin-2,4-diamine, 1′,5′,6′,7′-Tetrahydrospiro[cyclopentan-1,4′-cyclopentapyrimidin]-2′(3′ H)-imine und das 6-Phenyl-2,4-pyrimidindiamin

Guanidine reacts with cyclohexanone, cycloheptanone, acetone and 3-pentanone, resp., in a molar ratio 2∶1 to give the 1,3,5-triazaspiro[5.5]undeca-and [5.6]dodeca-1,3-dien-2,4-diamines3 a and3 b resp. and the 6,6-dimethylresp. diethyl-1,6-dihydro-1,3,5-triazin-2,4-diamines3 d and3 e resp. On the contrary, action of guanidine on cyclopentanone yields not3 c, but the 1′,5′,7′-tetrahydrospiro[cyclopentane-1,4′-cyclopentapyrimidine]-2′(3′H)-imines2 c, 5 c and6 c resp., which are 1∶2- and 1∶3-condensates. Phenylacetone is transformed by guanidine (1∶2) to give 6-phenyl-2,4-pyrimidindiamine (8 f). The structure of the compounds cited is proved by NMR-, IR-, and (partially) mass spectra. The different courses of the formation of3 a, b, d, e, 2 c, 5 c and6 c resp. and8 f are also discussed. The structural formulae of some additional bases, which were synthesized from guanidine and cyclopentanone, 3-pentanone and phenylacetone resp. could not be established.