Heterocyclic Functional Groups Research Articles

New Dual Inhibitors of Tyrosyl-DNA Phosphodiesterase 1 and 2 Based on Deoxycholic Acid: Design, Synthesis, Cytotoxicity, and Molecular Modeling.

Deoxycholic acid derivatives containing various heterocyclic functional groups at C-3 on the steroid scaffold were designed and synthesized as promising dual tyrosyl-DNA phosphodiesterase 1 and 2 (TDP1 and TDP2) inhibitors, which are potential targets to potentiate topoisomerase poison antitumor therapy. The methyl esters of DCA derivatives with benzothiazole or benzimidazole moieties at C-3 demonstrated promising inhibitory activity in vitro against TDP1 with IC50 values in the submicromolar range. Furthermore, methyl esters 4d-e, as well as their acid counterparts 3d-e, inhibited the phosphodiesterase activity of both TDP1 and TDP2. The combinations of compounds 3d-e and 4d-e with low-toxic concentrations of antitumor drugs topotecan and etoposide showed significantly greater cytotoxicity than the compounds alone. The docking of the derivatives into the binding sites of TDP1 and TDP2 predicted plausible binding modes of the DCA derivatives.

Removal of silver from chloride solutions using new polymer materials

This work presents the synthesis of polymer resins with heterocyclic functional groups, that is, N-(3-aminopropyl)-2-pipecoline, N-(3-aminopropyl)-2-pyrrolidinone, and trans-1,4-diaminocyclohexane for the recovery of Ag(I) from chloride solutions. The modification yield was 69.2, 74.6 and 88.3%, respectively. The best Ag(I) sorption was achieved from synthetic and real chloride solutions in the case of trans-1,4-diaminocyclohexane resin (sorption was 26.8 and 21.5 mg/g, respectively). The sorption kinetic data were well fitted to the pseudo-first-order kinetic model. The maximum sorption capacity of Ag(I) is 105.4, 117.8 and 130.7 mg Ag(I)/g for N-(3-aminopropyl)-2-pipecoline resin, N-(3-aminopropyl)-2-pyrrolidinone resin and trans-1,4-diaminocyclohexane resin, respectively. The trans-1,4-diaminocyclohexane modified resin was very selective towards Ag(I) compared to Cu(II), Pb(II), and Zn(II) from the real chloride leaching solution. The N-(3-aminopropyl)-2-pipecoline and N-(3-aminopropyl)-2-pyrrolidinone resins showed high preferences for Ag(I) over Pb(II) in real solution. These results indicated that the polymers can be applied in the recovery of Ag(I).

Biological Activities of Tetrahydroisoquinolines Derivatives

1,2,3,4-Tetrahydroisoquinoline (THIQ) is a common scaffold of many alkaloids isolated from several plants and mammalian species. THIQ derivatives possess a broad spectrum of biological activities, including antitumor, antitubercular, antitrypanosomal, antibacterial, anti-HIV, anti-inflammatory, anti-Alzheimer, and anticonvulsant ones.Aim. To cover updated studies on the biological properties of THIQ derivatives, as well as their structure-activity relationship (SAR), in order to highlight the effect of diverse functional groups responsible for the manifestation of the desired activity.Results and discussion. We have presented the review on biological activities of THIQ. The SAR studies show that the electron-donating, electron-withdrawing and some heterocyclic functional groups on the backbone plays a vital role in modulating the biological potential of the compounds synthesized.Conclusions. This review will help pharmaceutical researchers to synthesize novel and potent compounds containing THIQ scaffold.

Experimental and modelling waste rice husk ash as a novel green corrosion inhibitor under acidic environment

The ubiquitous role of green corrosion inhibitors and their adsorption nature unveils deeper insight into forming inhibitor-metal binding complexes. This work studied mild steel’s corrosion and mitigation behaviors under HCl 1 M solution with the newly waste rice husks inhibitor at the 298 K temperature. The liquid smoke (LS) inhibitor is synthesized and prepared from the waste rice husks with the help of the Pyrometallurgy process. The anti-corrosion performance was evaluated using Electrochemical Impedance Spectroscopy (EIS), Raman Spectroscopy, Scanning Electronic Microscopy and Machine Learning. Moreover, the time to corrosion method is considered to predict inhibitor duration at their respective concentration. Total Phenolic Content (TPC) advanced characterization was used to determine the amount of phenolic ligand’s molecule to donate its electron to 3d orbital of Fe. The inhibition efficiency stood at 97.73% of 80 ppm solution with approximate inhibition effectiveness for 17 days. The Raman Spectroscopy results show that LS comprises phenolic, cellulose, and complex heterocyclic functional groups. The latter becomes the key factor influencing the strength of inhibitors’ adsorption. The Raman Shift at approximately 3500–4000, 3000, 1800–2000, 800–1000 nm correlated to the presence of –OH, cellulose, C=O, and complex molecules. Furthermore, the experimental and modelling results are in good agreement. The Multicollinear Matrix shows a strong correlation between impedance and Bode phase angle. This work can be used as practical guidance to analyze and evaluate the effectiveness of inhibitors using intelligence systems and laboratory activities.

Correlations between the physicochemical properties of hydrochar and specific components of waste lettuce: Influence of moisture, carbohydrates, proteins and lipids

This study aims to figure out the influence of moisture content and chemical constitution, i.e. carbohydrates, proteins and lipids, of waste lettuce on the physicochemical structure of hydrochar produced via hydrothermal carbonization. The experimental results showed that homogenized carbon material can be obtained by hydrothermal treatment, regardless of the moisture content of feedstock. During the hydrothermal carbonization process of waste lettuce, carbohydrates were the most active reactants contributing to hydrochar formation. Meanwhile, Maillard reaction between proteins and carbohydrates occurred, which promoted the aromatization of the organic intermediates and increased the relative content of nitrogenous heterocyclic functional groups on the surface of hydrochar from 10.7 to 18.7%. Different from these two constitution, lipids did not participate in the carbonization reaction, the main hydrolyzates of lipids were adsorbed to the surface of hydrochar, leading to an increase in the mass of solid products.

Inherent vs Apparent Chemoselectivity in the Kumada-Corriu Cross-Coupling Reaction.

The Kumada-Corriu reaction is a powerful tool for C-C bond formation, but is seldom utilized due to perceived chemoselectivity issues. Herein, we demonstrate that high-yielding couplings can occur in the presence of many electrophilic and heterocyclic functional groups. Our strategy is mechanically based, matching oxidative addition rates with the rate of syringe pump addition of the Grignard reagent. The mechanistic reason for the effectiveness of this strategy is uncovered by continuous-infusion ESI-MS studies.

Three‐dimensionally ordered macroporous cross‐linked polystyrene incorporating functional groups via hydrophilic spacer arms: Application for heavy metal ion adsorption

AbstractThree‐dimensionally ordered macroporous cross‐linked polystyrenes (3DOM CLPS) with 2‐mercaptobenzothiazole (MBZ) groups attached directly or via hydrophilic spacer arms to frameworks were prepared for use as heavy metal ion adsorbents. The hydrophilic spacer arms are polyethylene glycol (PEG) chains with three different lengths. The functionalized 3DOM CLPS were characterized by SEM, FTIR, and elemental analysis. The results confirm that the MBZ groups have been introduced onto the pore wall of 3DOM CLPS directly or via PEGs, and the ordered structure was well preserved after functionalization. The functionalized 3DOM CLPS are effective adsorbents for the removal of heavy metal ions from solution, with adsorption capacities ranging from 0.25 to 1.14 mmol/g for silver (I) ions and 0.28 to 0.51 mmol/g for mercury (II) ions, respectively. The introduction of hydrophilic spacer arms between the 3DOM frameworks and the heterocyclic functional groups improves the adsorption capacities and adsorption kinetics. The adsorption capacities increase with the length of spacer arm. After regeneration by washing with acidic thiourea solution, the metal ion adsorption capacities of the regenerated 3DOM materials were on around 90% of the original capacities. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

Highly Chemo‐ and Regioselective Reduction of Aromatic Nitro Compounds Catalyzed by Recyclable Copper(II) as well as Cobalt(II) Phthalocyanines

AbstractCopper/cobalt phthalocyanines were established for the first time as catalysts for the very efficient chemo‐ and regioselective reduction of aromatic nitro compounds to generate the corresponding amines. The selective reduction of nitro compounds was observed in the presence of a large range of functional groups such as aldehyde, keto, acid, amide, ester, halogen, lactone, nitrile and heterocyclic functional groups. Furthermore, the present method was found to be highly regioselective towards the reduction of aromatic dinitro compounds in a short time with high yields. In most of the cases the conversion and selectivity were >99% as monitored by GC‐MS. The reduction mechanism was elucidated by UV‐vis and electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry.

Macroporous chelating resins incorporating heterocyclic functional groups via hydrophilic poly(ethylene oxide) spacer arms. II. Adsorption properties

AbstractSeveral new chelating resins prepared from macroporous chloromethylated polystyrene‐co‐divinylbenzene by either direct attachment of the heterocyclic functional groups, such as 2‐aminopyridine, 2‐amino‐5‐methylthio‐1,3,4‐thiadizole, 2‐amino‐5‐ethyl‐1,3,4‐thiadizole, and 2‐mercaptobenzothiazole, to the polymeric matrix or through different hydrophilic spacer arms were tested for the adsorption properties toward Hg2+, Ag+, Cd2+, and Pb2+ in an ammonium acetate buffer solution of pH 3.0. The results show that these resins exhibited a high affinity for Hg2+ and Ag+. The introduction of hydrophilic spacer arms between the polymeric matrix and heterocyclic functional groups resulted in an increase in the hydrophilicity and adsorption capacity of the resins. The presence of spacer arms made the kinetics of adsorption faster. The influence of the length of the spacer arm on the adsorption properties was also investigated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Macroporous chelating resins incorporating heterocyclic functional groups via hydrophilic PEG spacer arms. I. Synthesis and characterization

AbstractA series of novel chelating resins were synthesized by incorporating heterocyclic functional groups such as 2‐aminopyridine (AP), 2‐amino‐5‐methylthio‐1,3,4‐thiadizole (AMTZ), 2‐amino‐5‐ethyl‐1,3,4‐thiadizole (AETZ), and 2‐mercaptobenzothiazole (MBZ) into macroporous crosslinked polystyrene via a hydrophilic spacer arm of polyethylene glycol containing sulfur. Structures of the above‐mentioned resins were characterized by elemental analysis, Fourier transform‐infrared spectra (FTIR), ASAP‐2020 surface area and porosity analyzer, and scanning electron microscopy (SEM). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3220–3227, 2007

New synthesis of photocurable silanes and polysiloxanes bearing heterocyclic or olefinic functions

In this work, we described the synthesis of silanes and polysiloxanes bearing cationic photopolymerizable groups. Two new methods were used. The first one is the reaction between 3-mercapto-propyl-1-triethoxysilane ( 1) and chloromethylated olefins by a phase transfer catalysis. The second one is the radical addition of ( 1) or poly(dimethylsiloxane-co-methylmercaptopropylsiloxane) ( 9) to allyl or vinyl substituted heterocyclic monomers. These methods led to the expected adducts with an excellent yield. The polysiloxanes bearing heterocyclic functional groups linked through thioether bonds were photocurable by cationic route. Under UV light intensity of 17.5 mW/cm 2 , these polymers harden after 15 or 20 s.

MR spectra and azo-quinonehydrazone tautomerism in 4-arylazo-1-naphthol derivatives, without intramolecular proton transfer

Using13C-NMR spectroscopy conditions have been elucidated under which 4-R-azo-1-naphthol derivatives containing carbo- and heterocyclic functional groups R exist in solution predominantly in azo- or quinonehydrazone tautomeric forms, respectively. A mechanism has been proposed to account for azo-quinonehydrazone tautomerism; this mechanism would be expected to be valid in aprotic meida for hydroxyazo compounds which do not contain intramolecular hydrogen bonds.

Ortho-Disubstituted F-Benzenes. V. Intramolecular Heteroatom-facilitated ortho-Substitution of F-Benzene Derivatives with Oxazolinyl and Oxazinyl Groups

Abstract The oxazinyl and oxazolinyl substituents on an F-benzene ring facilitated the substitution of fluorine ortho to the heterocyclic functional groups by carbon and nitrogen nucleophiles. Alkylmagnesium halides and alkyllithium compounds were employed as the carbon nucleophile, and lithium N-methylanilide and N-methylanilinomagnesium halide as the nitrogen nucleophile. The selective ortho-substitution was accomplished by the complexing interaction between the ring-membered nitrogen on the functional substituents and the anionic nucleophile through the interposing metal cation. Effects of the substituents in the orientations and rates of the reactions depended upon the polarity of the reaction solvent and the kinds of anionic nucleophile and counter metal cation.

Ionic Polymerization of Vinyl Aromatic Monomers

Abstract The ionic polymerization of vinyl monomers possessing aromatic and heterocyclic functional groups has not been studied in any systematic fashion. Only in a few isolated cases have detailed mechanistic and structural studies been reported. The anionic polymerization of a number of vinylanthracene monomers has recently been investigated and some rationalization of this system is presented. The cationic and anionic polymerization of the N-, 3-, and 2-vinylcarbazole series of monomers is discussed in some detail. The important role of vinyl aromatic/vinyl heterocyclic monomers, i.e., diphenylethylene and the vinylcarbazoles, in elucidating the mechanistic aspects of cationic polymerization, “change transfer” polymerization, and photoionic polymerization is considered.