Carrying Amino Groups Research Articles

Synthesis of luminescent core–shell polymer particles carrying amino groups for covalent immobilization of enzymes

Synthesis of luminescent core–shell polymer particles carrying amino groups for covalent immobilization of enzymes

Amination of brominated nanoporous activated carbon beads for the preparation of CO2 adsorbents

Nanoporous activated carbon (NAC) beads that prepared by carbonization of microporous polymer 2,6-di-tert-butyl pyridine beads were subjected to bromination followed by amination to synthesize the NAC derivatives carrying amino groups. Grafted bromine groups, 0.41 mmol of Br per 1 g of NAC, are hydrolytic stable at 100 °С and can be successfully substituted by amino groups. SEM, TEM, and texture studies were shown a nanoporosity decrease. However, the aminated NAC beads maintained a narrow nanopore size distribution and high specific surface area, retaining a spherical shape. These beads were evaluated for capturing CO2 and showed good reversible adsorption capacity. The preparation method can easily be scaled up, and the NAC beads can be used for other adsorption applications where shaped carbon solids with developed nanoporosity are required.

Syntheses, Characterization, and X-ray Crystal Structure of Heteronuclear Zn/Na Assembled with Salen-type Schiff Base

Herein we reported the crystal structure of a dinuclear complex [{Zn^IINa^I (L)(EtOH)(NO₃)]}] (2) obtained by reaction with the metalloligand [Zn(L)].(H₂O) (1) and sodium nitrate. The metalloligand (1) and the dinuclear (2) complexes are characterized by IR and physical measurement. Spectroscopic evidence indicated that the Schiff base H₂L behave an N₂O₂O’ ₂ coordination tetradentate ligand. Suitable crystals of the compound 2 were grown by slow evaporation of ethanol solution for two weeks. The structure of 2 was elucidated by X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with a space group of <i>P2_1/c</i>. The asymmetric unit of the compound contains one dideprotonated ligand molecule, on tetracoordinated zinc (II) ion, one heptacoordinated sodium(I) ion, one bidentate nitrate group and one coordinated ethanol molecule resulting in a structure formulated as [Zn(<i>µ</i>-<i>L</i>)Na(NO₃)(EtOH)]. In the structure the Zn^II ion is tetracoordinated and the environment around the zinc (II) is best described as a planar square geometry. The Na^I ion is seven-coordinated in a severely distorted bipyramid pentagon environment. The interplanar angles between the two phenyl rings with a methoxy substituent is 4.208 (4)°, while the dihedral angle values of these groups with the phenyl carrying amino groups are respectively 7.499 (5)° and 11.594 (5)°. The Zn–Na distance is 3.4244 (9) Å. In the crystal structure numerous intramolecular and intermolecular hydrogen bonds link the molecules in a three-dimensional network.

Conjugation of methotrexate onto dedoped Fe3O4/PPy nanospheres to produce magnetic targeting drug with controlled drug release and targeting specificity for HeLa cells

Magnetic composite nanospheres carrying amino groups have attracted much interest due to their potential applications in the fields of catalysis, sensor, water purification, enzyme immobilization, DNA extraction, and drug delivery. In this paper, dedoped Fe3O4/polypyrrole (PPy) nanospheres with core–shell structure, high magnetization, superparamagnetism, and size meeting the demand of biorelated applications in vivo have been achieved by an in situ polymerization approach. The amount of the surface amino groups of Fe3O4/PPy is greatly enhanced by dedoping treatment due to liberation of the amino groups ever sheltered by the dopants, a situation that is responsible for facile conjugation of fluorescein and methotrexate (MTX) onto the magnetic composite through the EDC/NHS coupling chemistry to produce the desirable fluorescent Fe3O4/PPy/MTX targeting drug with a high MTX loading of ca. 109 μg mg−1. The as-obtained magnetic targeting drug exhibits controlled drug release, enhanced intracellular drug retention, and specific targeting ability to HeLa cells, presenting a promising candidate for treatment of cancer cells overexpressing folate receptors.

Synthesis of Steroid–Oligonucleotide Conjugates for a DNA Site-Encoded SPR Immunosensor

The excellent self-assembling properties of DNA and the excellent specificity of the antibodies to detect analytes of small molecular weight under competitive conditions have been combined in this study. Three oligonucleotide sequences (N(1)up, N(2)up, and N(3)up) have been covalently attached to three steroidal haptens (8, hG, and 13) of three anabolic-androgenic steroids (AAS), stanozolol (ST), tetrahydrogestrinone (THG), and boldenone (B), respectively. The synthesis of steroid-oligonucleotide conjugates has been performed by the reaction of oligonucleotides carrying amino groups with carboxyl acid derivatives of steroidal haptens. Due to the chemical nature of the steroid derivatives, two methods for coupling the haptens and the ssDNA have been studied: a solid-phase coupling strategy and a solution-phase coupling strategy. Specific antibodies against ST, THG, and B have been used in this study to asses the possibility of using the self-assembling properties of the DNA to prepare biofunctional SPR gold chips based on the immobilization of haptens, by hybridization with the complementary oligonucleotide strands possessing SH groups previously immobilized. The capture of the steroid-oligonucleotide conjugates and subsequent binding of the specific antibodies can be monitored on the sensogram due to variations produced on the refractive index on top of the gold chip. The resulting steroid-oligonucleotide conjugates retain the hybridization and specific binding properties of oligonucleotides and haptens as demonstrated by thermal denaturation experiments and surface plasmon resonance (SPR).

Efficient diborane-mediated synthesis of phthalocyanines carrying amino groups near the macrocycle

N-(3,4-dicyanophenyl)piperidine-2,6-dione (2) and 4-phthalimidophthalonitrile (3) were synthesized in 24% and 74% yield respectively, using 4-aminophthalonitrile as the starting material. Treatment of 2 and 3 with zinc acetate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene gave respectively phthalocyanines 4 and 5, whose reduction with diborane afforded dyes 6 and 7. Quaternization of 6 and 7 with iodomethane gave cationic zinc(II) phthalocyanines 8 and 9 respectively. A bathochromic shift was observed in the absorption spectra when amino and ammonium groups were present near the macrocycle in comparison with those dyes carrying alkylamino and quaternary alkyl ammonium salts as peripheral substituents.

Amino-functionalized basic catalysts with MIL-101 structure

Metal–organic framework (MOF) materials have only been scarcely explored for applications in heterogeneous catalysis in recent years. In addition to the use of MOFs as supports for the deposition of highly dispersed metal particles, the incorporation of active centers such as coordinatively unsaturated metal sites and the functionalization of the organic linkers with acidic or basic groups seem to be most promising. In our contribution, three different MOFs carrying amino groups at their organic linkers, namely Fe-MIL-101-NH2 (SBET=3438m2 g−1), Al-MIL-101-NH2 (SBET=3099m2 g−1) and CAU-1 (SBET=1492m2 g−1), were synthesized and tested in the Knoevenagel condensation of benzaldehyde with malononitrile and with ethyl cyanoacetate, respectively. It is shown that the expected products benzylidenemalononitrile (BzMN) and ethyl α-cyanocinnamate (EtCC) are formed with selectivities exceeding 99% and yields of 90 to 95% after 3h (for BzMN). Due to the very small pore windows of CAU-1 (0.3 to 0.4nm) the reaction proceeds much slower over this catalyst in comparison to the amino-MIL-101 derivatives, which possess open pore windows of up to 1.6nm. Moreover, the catalyst Al-MIL-101-NH2 is recyclable without significant loss of activity.

Polydiacetylenes carrying amino groups for colorimetric detection and identification of anionic surfactants

A series of diacetylene lipids carrying primary amine, secondary amine or ammonium head groups are prepared and converted to blue polydiacetylene (PDA) sols by UV irradiation. The blue to pink colorimetric transition of polymerized diacetylenes in the presence of anionic surfactants such as sodium dodecanoate (SDC), sodium docecyl sulphate (SDS), and sodium dodecyl benzene sulphate (SDBS) are observed by the naked eye at the micromolar concentration level while there is no change with cationic surfactants and little response with nonionic surfactants. An identification of common anionic surfactants can be accomplished based on a combination of the colorimetric pattern of structurally diverse PDAs using the principal component analysis technique. Moreover, PDA was successfully fabricated on filter paper and the colorimetric response of PDA embedded on the paper was investigated which allowed the direct colorimetric detection of anionic surfactants.

ChemInform Abstract: New Type of Phosphorus Compounds Containing Sulfur and Selenium

New type of phosphorus compounds containing the P=S or P=Se groups were prepared by utilization of sterically protecting group carrying amino groups with the aid of intramolecular coordination effect.

Alternating Ring-Opening Metathesis Copolymerization of Amino Acid Derived Norbornene Monomers Carrying Nonprotected Carboxy and Amino Groups Based on Acid−Base Interaction

Amino acid derived norbornene monomers having carboxy (1) and amino groups (2) were synthesized and subjected to ring-opening metathesis copolymerization with various feed ratios using the Grubbs second generation ruthenium catalyst. The M(n)'s of the copolymers ranged from 5300 to 9400 (M(w)/M(n) = 1.40-1.69). The monomer conversion and M(n) of the copolymer were maximized when the monomer feed ratio was 1:1. The monomer unit ratios in the copolymers were almost 1:1 at 10% conversion, irrespective of the feed ratios. The monomer reactivity ratios r(1) and r(2) were estimated to be 0.08 and 0.02, which confirmed that alternating copolymerization occurred. It is considered that alternating copolymerization is brought about by the acid-base interaction between the monomers and/or between the propagating polymer end and the incoming monomer.

Complement activation on surfaces carrying amino groups

The complement system is strongly activated by surfaces carrying nucleophilic groups, such as hydroxyl (OH) groups, and triggered by deposition of complement protein fragment, C3b. Surfaces carrying amino groups, the other representative nucleophilic group, are expected to be potential activators of the complement system through the alternative pathway. Few studies thus far have examined the potential of artificial materials carrying amino groups in activating the complement system. In this study, we employed a self-assembled monolayer (SAM) of 11-amino-1-undecanethiol (NH 2-SAM) and a polyethyleneimine (PEI)-coated surface as model surfaces to study interactions between amino groups and serum complement pathway. SAMs of 11-mercaptoundecanol (OH-SAM) and 1-dodecanethiol (CH 3-SAM) were used as control surfaces, respectively. Although much protein was adsorbed from serum solutions on the two types of amino surfaces, amounts of C3b deposition were much less than those observed on OH-SAM. Amounts of C3a released on the amino surfaces were same levels as that of CH 3-SAM, but significantly smaller than that on OH-SAM. These facts suggest that the nucleophilic amino groups on NH 2-SAM and PEI-coated surfaces do not directly activate the alternative pathway, but the protein adsorbed layers formed on amino surfaces activate it, but to an extent much smaller than that on OH-SAM. In addition, we found no deposition of C1q molecules on the amino surfaces, suggesting that these surfaces fail to activate the classical pathway. However, more careful studies are needed to conclude it, because it is known that C1q is only transiently detected at typical classical activation interfaces.

Synthesis of Some Novel Azido‐ and Tetrazoloquinoline‐3‐carbonitriles and Their Conversion into 2,4‐Diaminoquinoline‐3‐carbonitriles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of some novel azido- and tetrazoloquinoline-3-carbonitriles and their conversion into 2,4-diaminoquinoline-3-carbonitriles

Quinoline-3-carbonitriles carrying amino groups at the 2- and/or 4-position have been prepared via the corresponding azido- or tetrazolo-quinolines, through the intermediacy of phosphazenes.

Synthesis and characterization of a poly(N-isopropylacrylamide) with β-cyclodextrin as pendant groups

A novel linear poly(N-isopropylacrylamide) (PNIPA) with β-cylodextrin (β-CD) moiety (PNIPA-β-CD) was synthesized by the conjugation of β-CD carrying amino groups (EDA-β-CD) onto PNIPA with epoxy groups (P(NIPA-co-GMA), M n = 3.86 x 10 4 ), and the related reaction conditions are investigated. PNIPA-β-CD was characterized by means of IR, NMR and UV spectroscopes, element analysis, and differential scanning calorimetry (DSC). The number-average molecular weight (M n ) and the β-CD content of the obtained PNIPA-β-CD are 4.87 x 10 4 and 18.8 wt %, respectively. PNIPA-β-CD can not only respond to temperature stimuli but also include guest molecules. Lower critical solution temperature (LCST) of aqueous PNIPA-β-CD solution is similar to that of PNIPA. The association constant (K a ) for PNIPA-β-CD with methyl orange (MO) is 2.4 x 10 3 L mol -1 at pH 1.4, which is comparable to that of EDA-β-CD (K a = 2.9 x 10 3 L mol -1 ).

Synthesis of Neomycin Analogs to Investigate Aminoglycoside-RNA Interactions

A series of novel aminoglycoside oligosaccharide analogs containing a 2,5-dideoxystreptamine core scaffold was prepared to study aminoglycoside binding to the small subunit of 16S rRNA. A set of monosaccharide building blocks carrying amino groups in different positions and conformations around the pyranose ring was utilized in the assembly of oligosaccharides. These aminoglycoside analogs were analyzed for their RNA-bind ing capacity using a high throughput mass spectroscopy assay.

New Type of Phosphorus Compounds Containing Sulfur and Selenium

New type of phosphorus compounds containing the P=S or P=Se groups were prepared by utilization of sterically protecting group carrying amino groups with the aid of intramolecular coordination effect.

Control of the DNA-Binding Specificity of 9,10-Anthraquinone by the Nature and Positions of Substituents

Anthraquinone intercalator 1s carrying amino groups through a spacer at positions 1 and 8 of the ring stabilized calf thymus DNA more than poly [d(A-T)]2 and polydApolydT. By contrast, N-acetylated derivative 2s stabilized the AT polymers more and showed preference for poly[d(A-T)]2 to polydApolydT. This result is explained by postulating that the terminal acetylamino groups interact with adenines in the major groove of DNA and that the symmetric disposition of the substituents of 2s matches that of the alternating A-T sequence of poly[d(A-T)]2.

New carbamate supports for the preparation of 3′-amino-modified oligonucleotides

A novel approach for the preparation of oligonucleotides carrying amino groups at the 3′-end is described. Several CPG supports having aminoalkyl groups and 3′-amino-2′, 3′-dideoxynucleosides linked through base-labile carbamate linkages such as 2-(2-nitrophenyl)ethoxycarbonyl and fluorenylmethoxycarbonyl were prepared using two different strategies. These supports are compatible to the standard solid phase phosphite-triester methodology and yield oligonucleotides containing amino groups at the 3′-end. Several properties of the 3′-amino oligonucleotides, such as nuclease resistance, hybridization, and preparation of oligonucleotide conjugates are discussed.

The chloroperoxidase-catalyzed oxidation of phenols. Mechanism, selectivity, and characterization of enzyme-substrate complexes.

The reactivity of a series of para-substituted phenolic compounds in the peroxidation catalyzed by chloroperoxidase was investigated, and the results were interpreted on the basis of the binding characteristics of the substrates to the active site of the enzyme. Marked selectivity effects are observed. These operate through charge, preventing phenolic compounds carrying amino groups on the substituent chain to act as substrates for the enzyme, and through size, excluding potential substrates containing bulky substituents to the phenol nucleus. Also, chiral recognition is exhibited by chloroperoxidase in the oxidation of N-acetyltyrosine, where only the L isomer is oxidized. Kinetic measurements show that, in general, the efficiency of chloroperoxidase in the oxidation of phenols is lower than that of horseradish peroxidase. Paramagnetic NMR spectra and relaxation rate measurements of chloroperoxidase-phenol complexes are consistent with binding of the substrates close to the heme, in the distal pocket, with the phenol group pointing toward the iron atom. On the other hand, phenolic compounds which are not substrates for chloroperoxidase bind to the enzyme with a much different disposition, with the phenol group very distant from the iron and probably actually outside the active-site cavity.

New indole and triazino[5,4-b]indol-4-one derivatives: synthesis and studies as inotropics and inhibitors of blood platelet aggregation.

New triazino[5,4-b]indol-4-one derivatives carrying amino groups in position 3 were synthetized and tested as inotropic agents and inhibitors of platelet aggregation. 2h, 2p, 5p, and 6g are the most active as inotropic agents. Compounds were tested as inhibitors of platelet aggregation induced by adenosine 5'-diphosphate (ADP) and arachidonic acid (AA) (guinea pig whole blood). 2k, 2p, 5o, 6d, 6m, and 6o are the most active as inhibitors of the platelet aggregation induced by AA. 6d, 6h, and 6o are most active compounds also in the aggregation induced by ADP. Radioimmunoassay studies, following AA induced aggregation, measuring thromboxane B2 (TXB2) and prostaglandin E2 (PGE2) were carried out on compounds 2b, 2d, 2f, 2g, 2h, 2i, 2k, 2m, 2o, 2p, 2r, 5i, 5j, 5k, 5r, and 5f, which inhibit platelet aggregation induced by AA. None of the compounds tested turned out to be selective inhibitors. Compounds 2h and 2p showed both inotropic and platelet aggregation inhibiting activity.