Synthesis of Novel Pyrazole Derivatives as Antineoplastic Agent

Anticancer evaluation of pyrazole 2 and Schiff base 5 is reported. Synthesis of some important heterocyclic compounds via 2,3‐diaryloxirane‐2,3‐dicarbonitrile 1 , pyrazole 2 , and Schiff base 5 with different nitrogen nucleophiles afforded new routes for synthesized fused heterocyclic derivatives. These compounds can be used as a key starting materials to synthesize some important imidazolo‐[4,5‐c ]pyrazole, pyrazolo[3,4‐e ]1,2,4‐triaging, imidazolo[3,2‐b ]pyrazole, and pyrazolo‐pyrazine, as anticancer reagents showed good results at optimum conditions (400–500 ppm), particularly the bridge head nitrogen compounds, and could be used to improve them. Electromeric effect of the halogen atom in the aryl moieties can be controlled upon the rate of reaction and the yield of the product. The structure of the synthesized new compounds would be characterized by elemental and spectral data.     

A Three‐Component Assembly Promoted by Boronic Acids Delivers a Modular Fluorophore Platform (BASHY Dyes)

The modular assembly of boronic acids with Schiff‐base ligands enabled the construction of innovative fluorescent dyes [boronic acid salicylidenehydrazone (BASHY)] with suitable structural and photophysical properties for live cell bioimaging applications. This reaction enabled the straightforward synthesis (yields up to 99 %) of structurally diverse and photostable dyes that exhibit a polarity‐sensitive green‐to‐yellow emission with high quantum yields of up to 0.6 in nonpolar environments. These dyes displayed a high brightness (up to 54 000 m ^?1 cm^?1). The promising structural and fluorescence properties of BASHY dyes fostered the preparation of non‐cytotoxic, stable, and highly fluorescent poly(lactide‐co‐glycolide) nanoparticles that were effectively internalized by dendritic cells. The dyes were also shown to selectively stain lipid droplets in HeLa cells, without inducing any appreciable cytotoxicity or competing plasma membrane labeling; this confirmed their potential as fluorescent stains.     

含硅二烃基锡(Ⅳ)水杨醛缩氨基硫脲席夫碱配合物的合成、结构及抗癌活性

合成了11个含硅二烃基锡的水杨醛缩氨基硫脲席夫碱配合物R(Me3SiCH2)SnL(R=Me3SiCH2或Ph,Cy;H2L=水杨醛缩氨基硫脲席夫碱),并通过1H NMR、13C NMR、IR、元素分析和X射线单晶衍射对目标化合物结构进行了表征。结果表明,水杨醛缩氨基硫脲席夫碱作为三齿双阴离子配体,通过酚氧、亚胺氮和硫醇硫与锡(Ⅳ)配位,形成了中心锡原子为五配位的五元杂环与六元杂环的并联结构。生物活性试验的初步结果显示,该类化合物对人体乳腺癌细胞MDA-MB-231和MCF-7具有较好的体外抗癌活性。     

Synthesis,biological evaluation of antioxidant-antibacterial activities and computational studies of novel anthracene- and pyrene-based Schiff base derivatives

Schiff base derivatives with anthracene- and pyrene-based units, A1-A6 and P1-P6 were synthesized (89%–99% yields). Schiff base derivatives were designed to possess an heterocyclic moiety on one side to enhance the coordination ability towards metals. To investigate the biological assay of the newly synthesized compounds, their DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging, metal chelating, reducing power, antibacterial and DNA binding activities were tested. A6 (63.1%) showed the maximum free radical scavenging activity among all. However, compound P3 at concentration of 200 μg/mL possessed the highest metal chelating (45.8%) activity and power of reduction. In addition, P3 and A6 showed antibacterial activity against all bacteria tested and both compounds were very well bound to CT-DNA. Density functional theory method with B3LYP/6-311++G(d,p) basis set was performed to get information about the structural and electronic properties of the present compounds. In addition, the metal coordination properties of the dimers of the parent Schiff bases were investigated through interactions with Zn²⁺.     

Some Corrosion Inhibitors Based on Schiff Base Surfactants for Mild Steel Equipments

Two series of Schiff base amphiphiles were prepared throughout condensation of benzaldehyde or anisaldehyde and three different fatty amines with various alkyl chain length; namely: dodecyl, hexadecyl and octadecyl amine. The chemical structures of the prepared Schiff bases were confirmed using elemental analysis, FTIR, and ¹H-NMR spectra. The data of structural analysis for these compounds were confirmed the chemical structures and the purity of the synthesized amphiphiles. The synthesized Schiff base amphiphiles were evaluated as corrosion inhibitors for low carbon steel (mild steel) in various acidic media (HCl and H₂SO₄) using weight loss technique. The corrosion inhibition measurements of these inhibitors showed high protection of the low carbon steel alloys against corrosion process in the tested acidic media at different periods as well as they have good biocidel effectagainest SRB. The discussion was correlated the efficient corrosion inhibition of these inhibitors to their chemical structures.     

Synthesis,characterization and dyeing performance of new bisazo–bisazomethine disperse dyes

New bisazo–bisazomethine disperse dyes were prepared by the coupling of diazotized solutions of various aromatic amines with 2,2′-{methylenebis[4,1-phenylenenitrilomethylylidene]}diphenol (Schiff base). Schiff base (SB) was prepared by the condensation of 2-hydroxybenzaldehyde with 4,4′-diaminodiphenylmethane (DDM). The resultant dyes were characterized by elemental analysis, IR and ¹H NMR spectral studies. The UV–visible absorption spectral data were investigated in dimethylformamide (DMF) and are discussed in terms of structure property relationship. The dyes when applied on polyester fabric, gave golden yellow to reddish brown shades having fairly good to good light fastness, very good to excellent washing, perspiration and sublimation fastness and good to very good rubbing fastness properties.     

Synthesis and characterization of some metal complexes of isonitroso-2-acetylnaphthalene derivative

Nickel(II), copper(II), and zinc(II) complexes with the Schiff base obtained from isonitroso-2-acetylnaphthalene and 1,2-phenylenediamine were synthesized. The compounds were characterized by elemental analyses, FT-IR, UV-Vis, and ¹H and ¹³C NMR spectra, conductance measurements, magnetic susceptibility measurements, and thermal analysis. The results suggest tetradentate coordination of the symmetrical Schiff base ligand through the two oxime oxygen atoms and two azomethine nitrogen atoms. The molar conductance data showed that the synthesized complexes are non-electrolytes.     

Synthesis,characterization, crystal structures and antibacterial activities of some Schiff bases with N<Subscript>2</Subscript>O<Subscript>2</Subscript> donor sets

A series of Schiff base compounds were synthesized by the reaction of different 3,5-dihalosalicylaldehyde (halo atoms equal to Cl, Br and I) with polymethylenediamines of varying chain length. The Schiff bases were characterized using FT-IR, UV–Vis, ¹H NMR, ¹³C NMR and mass spectroscopic techniques, and elemental analyses (CHN), and crystal structure of some compounds was determined by X-ray crystallography. The in vitro biological screening effects of the synthesized compounds were tested against different microbial kinds. The results revealed that all compounds were biologically active.     

Inhibitory study of some novel Schiff base derivatives on Staphylococcus aureus by microcalorimetry

The effect of a series of novel Schiff base compounds on Staphylococcus aureus was studied by microcalorimetric method at 37 °C The results showed that all of the organic compounds had the capacity to inhibit the growth of S. aureus in different extent. And the extent and duration of the inhibitory effect on the growth of S. aureus, judged from the rate constant (k), varied with the different structure of the Schiff base compounds. According to the power-time curves, the multiplication rate constant and inhibition ratio were calculated. The growth rate constant of S. aureus (in log phase) in the presence of Schiff base compounds decreased with the increasing of the concentrations of these compounds regularly. The experimental results revealed that the hydrophilicity of Schiff bases had a great influence on their antibacterial activity. Of these Schiff bases, the greater their hydrophilicity, the higher their antibacterial activity. The antibacterial structure-activity relationship (SAR) of Schiff base derivatives was also briefly discussed.     

Synthesis and Biological Evaluation of some 3d Metal Complexes with a Novel Heterocyclic Schiff Base

A heterocyclic Schiff base was prepared by condensing 3‐acetylcoumarin with 2‐amino‐3‐carboxyethyl‐4,5,6,7‐tetrahydrobenzo[b ]thiophene. Such Schiff bases derived from two different heterocyclic moieties are rare and expected to have properties surpassing those of either of the parent compounds in effectiveness of complex formation and biological activities. This ligand formed a series of complexes with manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) ions. The ligand and the metal complexes were characterized by various physicochemical and spectral studies. These included elemental analysis, molar conductance, magnetic susceptibility, as well as UV–vis, IR, ¹H NMR, ¹³C NMR, and ESR spectral studies. The ESR spectral data adequately supported the covalent nature of the metal–ligand bonds. The ligand possessed a hexagonal crystal structure, but on complexation the crystallinity was lost. The fluorescence spectra of the ligand and its metal complexes in DMSO were also recorded. The ligand and the metal complexes were screened for their antimicrobial activities, and it was observed that the metal complexes are more active than the ligand. The α‐amylase inhibitory activity and the DNA cleavage activity of the ligand and the metal complexes were also examined. in vitro antitumor activity of the copper(II) complex was assayed against human cervical carcinoma cells (HeLa cell line), showing that the complex exhibited promising antitumor activity on the HeLa cell line.     

Synthesis and application of disazo reactive dyes derived from sulfatoethylsulfone pyrazolo[1,5-a]pyrimidine derivatives

Two models of heterocyclic reactive dyes based on disazo pyrazoloprymidine derivatives and possessing a sulfatoethylsulfone reactive group were synthesized and characterized by elemental analysis, IR and ¹H NMR spectroscopy. The dyes were applied to cotton, wool and silk fabrics. Effects of varying dyeing conditions were investigated. The results assessed for the exhaust dyeing methods on the different fabrics indicate that these reactive dyes showed high exhaustion and fixation values. The dyed fabrics also showed very good light fastness and good to excellent washing, rubbing and perspiration fastness.     

Synthesis,physicochemical elucidation,biological screening and molecular docking studies of a Schiff base and its metal(II) complexes

A Schiff base 1-((3-nitrophenylimino)methyl)naphthalen-2-olate (HL) and its two novel complexes with Zn(II) and Co(II) metals were successfully synthesized and characterized by FTIR, ¹H NMR, ¹³C NMR, elemental analysis, magnetic susceptibility, TGA and EIS-MS. Crystal of Schiff base was also characterized by X-ray analysis and experimental parameters were found in line with the theoretical parameters. Quantum mechanical approach was also used to compare structural and calculated parameters and to ensure the geometry of metal complexes. The photometric behaviors of all the synthesized compounds were investigated in a wide pH range using BR buffers. Appearance of isosbestic point suggested the existence of Schiff base molecules in different tautomeric forms. Binding of synthesized complexes with calf thymus DNA was explored by photometric and voltammetric titrations and binding constants were calculated. The results indicated that ligand and its metal complexes bind to DNA by intercalation mode. Docking studies indicate their binding possibilities with topoisomerase II. Moreover, all these prepared compounds were screened for enzyme inhibition, antibacterial, cytotoxic and in vivo antidiabetic activities and found active against one or other activity. This effort just provides preliminary data for some biological properties and which can act as foundation stone for their application in drug development.     

Spectroscopic investigation of novel donor–acceptor chromophores as specific application agents for opto-electronics and photonics

Donor–acceptor chromophores were synthesized by Knoevenagel condensation and characterized by using spectroscopic measurements (FT-IR, ¹H NMR, ¹³C NMR, and mass) and elemental analyses. UV–Vis and fluorescence spectroscopic studies provided that these dyes are good absorbent and fluorescent. The results of photostability study showed that photobleaching of Dyes 2 and 4 was more significant than that of Dyes 1 and 3, providing that Dyes 1 and 3 are more photostable than Dyes 2 and 4. In addition, all dyes included in this study are found to be sensitive to the polarity of the microenvironment provided by different solvents based on the results of fluorescence polarity studies.     

Microwave‐Assisted Synthesis of Arylazoaminopyrazoles as Disperse Dyes for Textile Printing

The synthesis of heterocyclic azo‐dyes via conventional heating and microwave (MW) heating was investigated. From a sequence of reactions starting from cyanoacetic acid, 4‐arylazo‐2H‐pyrazol‐3‐ylamines and 4‐arylazo‐2‐phenyl‐2H‐pyrazol‐3‐ylamines were obtained. The structures these compounds were obtained by inspection of spectroscopic and analytical techniques including ¹H and ¹³C NMR spectroscopy, IR spectroscopy, mass spectrometry, and elemental analysis. The fastness properties and UV/Vis absorption spectroscopic data of these disperse dyes in printing polyester fabrics were investigated.     

Synthesis,DFT calculations,cyclic voltammetry and antibacterial activities of a new blue-violet dye and a new blue-green fluorescent heterocyclic system

The new blue-violet dye 2-(3-hydroxyimino-2,3-dihydroimidazo[1,2-a]pyridin-2-yliden)-2-(2-thienyl)acetonitrile was prepared in high yield from the reaction of 3-nitroimidazo[1,2-a]pyridine with 2-(2-thienyl)acetonitrile by nucleophilic substitution of hydrogen. Acylation of the hydroxyl group led to a new heterocyclic system, (pyrido[2′,1′:2,3] imidazo[4,5-b]thieno[2,3-e]pyridine-11-carbonitrile) with very strong blue-green fluorescent properties. Physical, spectral and analytical data have confirmed the structures of the synthesized dyes. The optical and solvatochromic properties of these compounds were investigated and showed interesting photophysical properties. Density functional theory calculations of blue-violet and fluorescent dyes were performed to provide the optimized geometries, Mulliken atomic charges, relevant frontier orbitals and the prediction of ¹H NMR chemical shifts. The electrochemical properties of these dyes were investigated by cyclic voltammetry and an oxidation wave was observed at a half-wave potential of −0.143 V versus SCE for the blue-violet dye. Also, these new compounds exhibited potent antibacterial activity against Gram positive and negative bacterial species.     

Synthesis and spectroscopic characterization of asymmetric Schiff bases derived from 4′-formylbenzo-15-crown-5 containing recognition sites for alkali and transition metal guest cations

Asymmetric salen-type Schiff base ligands have been synthesized via a stepwise approach. In the first step, mono-Schiff base compounds were prepared by condensation of salicylaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy-5-methoxybenzaldehyde and 2-hydroxy-1-naphthaldehyde with hydrazine hydrate. These compounds were then reacted with 4′-formylbenzo-15-crown-5 to prepare asymmetric ligands. ¹H-NMR spectra indicate that the mono- and asymmetric bis-Schiff base compounds exist in both (E) and (Z) isomeric forms in CDCl₃ solution. The asymmetric crown compounds form crystalline 1:1 (Na⁺:ligand) complexes with sodium perchlorate. Homo-metallic Ni(II) and Zn(II) complexes with 1:2 (metal:ligand) stoichiometries have also been synthesized. The results indicate that the Schiff base ligands coordinate through the azomethine nitrogen and phenolic oxygen.     

Synthesis,characterization, and dyeing performance of some azo thienopyridine and thienopyrimidine dyes based on wool and nylon

A string of novel heterocyclic mono azo dyes were synthesized and their utilization in dyeing different fabrics as wool and nylon were discussed. Thienopyridine azo dyes 4 and 6 were prepared by reaction of chloro acetamidederivative 2 with diamino compounds to yield 3 and 5 , followed by reaction with NaNO₂/HCl and coupling with nucleophilic reagent. One-pot reaction of chloro acetamide 2 with ammonium thiocyanat in solvent ethanol gave the unexpected thienopyrimidine derivative 7 , which contain two active sites, the former is primary amine that was able to form diazonium salt that coupled with N,N-dimethylaniline, resorcinol, and/or self-coupling to afford the azo dyes 8-10 , and the latter is active methylene group that underwent coupling with different diazonium salts to give the azo thienopyrimidine derivative dye 11-15 . The dyeing performance of these azo dyes had been investigated in terms of their dyeing behavior and fastness properties on different fabrics. Results showed that the color strength (K/S) values, as well as, washing, rubbing, and resistance to acid, alkali and light showed high efficiency of these heterocyclic mono azo dyes to dye wool rather than nylon fibers.     

Facile synthesis of some novel triazolo[3,4-b]thiadiazines and triazolo[4,3-b]tetrazines

4-Amino-5-ethyl-4H-1,2,4-triazole-3-thiol was used as a key intermediate for the synthesis of triazolo[3,4-b][1,3,4]thiadiazines, triazolo[4,3-b][1,2,4,5]tetrazines and Schiff’s base via reactions with various hydrazonoyl halides and salicyaldehyde, respectively. Moreover triazolyl-N-N′-triazole derivatives were prepared from reaction of Schiff’s base with various hydrazonoyl halides. The structures of all the newly synthesized heterocyclic compounds were established by considering elemental analysis and spectral data.     

Preparation of some new coumarin dyes

Series of coumarins containing heterocyclic substituent in 3-position were prepared. Sulfonyl chloride, a reactive group, was drawn into the heterocycle, and further condensed with amines to give series of new compounds that contain N-alkyl sulfamide. The spectral properties and dyeing character of these new dyes are discussed. A bathochromic shift (10 nm), enhanced fastness in light and sublimation (1-2 grade) and larger molar extinction coefficient (increase 104 L ·mol-1 ·cm-1) are apparent with these new compounds. In the meantime, larger solubility appears with these new compounds.     

Synthesis, characterization and some properties of epoxy resins containing azomethine bonding

New epoxy resins were prepared from hydroxyl substituted Schiff base monomers in two steps. The first step is based on the synthesis of hydroxyl substituted Schiff base monomers via condensation reaction. The second step includes the reaction between Schiff base monomers with epichlorohydrine (EPC) to obtain epoxy resins. The structures of resulting compounds were confirmed by FTIR and ¹H-NMR. TG-DTA and DSC measurements were made for thermal characterizations of the compounds. Chemical resistances of the cured epoxy-amine systems in acidic, alkaline and organic solvents were determined for coating applications. HCl (aqueous solution, 10%), NaOH (aqueous solution, 10%), DMSO, DMF, N-methylpyrrolidone, ethanol, THF and acetone were used for corrosion tests. Chemical resistance data show that the synthesized resins have good chemical resistance against various acid, alkaline and common organic solvents.