Aniline Residue Research Articles

5-Aryl-2,2′-bipyridines bearing fluorinated anilines residues at C6 position: synthesis and photophysical properties

A convenient synthetic approach to 5-aryl-2,2′-bipyridines bearing a (poly)fluorine-containing aniline residue at position C6 based on sequential ipso-substitution of the cyano group at position C5 of 3-(2-pyridyl)-1,2,4-triazines and the aza-Diels–Alder reaction has been proposed. The influence of the number and the position of the fluorine atoms on the reactivity of fluoroanilines has been estimated by means of DFT calculations. It was shown that the reaction cannot be realized if a nitro group is present in the ortho-position or two fluorine atoms occupied the ortho-positions in aniline. Photophysical properties of prospective “push–pull” fluorophores have been studied. Incorporation of fluorine atom into position 4 of aniline fragment in 5-p-tolylbipyridines causes small bathochromic shift of emission maximum, whereas the replacement of the methoxy group at the position C4 of the aniline moiety in 5-(4-methoxyphenyl)-2,2′-bipyridine with fluorine atom leads to a significant hypsochromic shift of emission maximum and to significant increase in quantum yield; the positive solvatochromism has been observed.

A biochar modified nickel-foam cathode with iron-foam catalyst in electro-Fenton for sulfamerazine degradation

A nickel-foam cathode modified by a self-nitrogen-doped biochar derived from waste giant reed was synthesized. The fabricated cathode (B@Ni-F) proved to be with high oxygen reaction reactive (ORR) reactivity and H2O2 selectivity (70.41%) owing to the enrichment of oxygen functional groups and pyridinic N when low-temperature pyrolyzed biochar was incorporated. The charge transfer resistance of B@Ni-F decreased to 7.18 Ω, which was 95.7 Ω for the original nickel-foam, proving by electrochemical impedance spectroscopy (EIS). Expectedly, Its H2O2 accumulation improved 14 times, thus making it comparable with commonly used electrodes like carbon cloth and graphite plate. Subsequently, B@Ni-F cathode and iron-foam (Fe-F) catalyst were firstly used in the electro-Fenton (EF) process for sulfamerazine (SMR) degradation. Double-functional polyphosphate electrolytes including tetrapolyphosphate (4-TPP), tripolyphosphate (3-TPP), pyrophosphate (PP) and Na3PO4 were compared with the conventional Na2SO4 electrolyte in EF for SMR degradation. The absolute rate constant for oxidation of SMR by OH was determined to be (3.4 ± 0.09) × 109 M−1 s−1. SMR degradation enhancement in the presence of polyphosphate-based electrolytes is associated with bulk OH generation from Fe2+- polyphosphate ligand complexes via O2 activation. The Fe2+-3-TPP complexes have relatively higher oxidation ability compared to Fe2+-PP, Fe2+-PO4 species. A plausible SMR oxidation pathway is proposed based on the by-products detected by UPLC-MS/MS and density functional theory (DFT) calculations. The dominant SMR degradation pathway was hydroxylation of aniline residue of SMR, followed with the cleavage of SN and then breakage of aromatic rings.

The Development of Tyrosyl-DNA Phosphodyesterase 1 (TDP1) Inhibitors Based on the Amines Combining Aromatic/Heteroaromatic and Monoterpenoid Moieties

Background: Inhibition of the DNA repair enzyme, tyrosyl-DNA phosphodiesterase 1 (TDP1), may increase the efficacy of cancer drugs that cause damage to tumor cell DNA. Among the known TDP1 inhibitors, there are compounds containing moieties of natural substances, e.g., monoterpenoids. In this work, we synthesized several compounds containing aromatic/ heteroaromatic amines and monoterpenoid groups and assessed their TDP1 inhibition potential. Methods: Structures of all the synthesized compounds were confirmed by 1H and 13C NMR as well as HRMS. The TDP1 inhibitory activity of the amines was determined by real-time fluorescence oligonucleotide biosensor. Results: The synthesized secondary amines had TDP1 inhibitory activity IC50 in the range of 0.79-9.2 µM. The highest activity was found for (–)-myrtenal derivatives containing p-bromoaniline or m-(trifluoromethyl)aniline residue. Conclusion: We synthesized 22 secondary amines; of these, 17 amines are novel chemical structures. Many of the amines inhibit TDP1 activity in the low micromolar range. Therefore, these compounds are promising for further study of their antiproliferative activity in conjunction with DNA damaging drugs.

A designer enzyme for hydrazone and oxime formation featuring an unnatural catalytic aniline residue.

Creating designer enzymes with the ability to catalyse abiological transformations is a formidable challenge. Efforts toward this goal typically consider only canonical amino acids in the initial design process. However, incorporating unnatural amino acids that feature uniquely reactive side chains could significantly expand the catalytic repertoire of designer enzymes. To explore the potential of such artificial building blocks for enzyme design, here we selected p-aminophenylalanine as a potentially novel catalytic residue. We demonstrate that the catalytic activity of the aniline side chain for hydrazone and oxime formation reactions is increased by embedding p-aminophenylalanine into the hydrophobic pore of the multidrug transcriptional regulator from Lactococcus lactis. Both the recruitment of reactants by the promiscuous binding pocket and a judiciously placed aniline that functions as a catalytic residue contribute to the success of the identified artificial enzyme. We anticipate that our design strategy will prove rewarding to significantly expand the catalytic repertoire of designer enzymes in the future.

X‐ray crystal structures and MMA polymerization of cadmium(II) complexes with bidentate pyrazole ligands: the formation of monomers or dimers as a function of a methyl substituent on the pyrazole and aniline rings

The reaction of CdBr2·4H2O with ancillary ligands, N,N‐bis(1H‐pyrazolyl‐1‐methyl)aniline (L1), N,N‐bis(1H‐pyrazolyl‐1‐methyl)‐p‐methylaniline (L2), N,N‐bis(1H‐pyrazolyl‐1‐methyl)‐3,5‐dimethylaniline (L3), N,N‐bis(3,5‐dimethyl‐1H‐pyrazolyl‐1‐methyl)aniline (L4) and N,N‐bis(1H‐pyrazolyl‐1‐methyl)‐2,6‐dimethylaniline (L5) in ethanol yields novel Cd(II) bromide complexes, [L1CdBr2]2, [L2CdBr2]2, [L3CdBr2]2, [L4CdBr2] and [L5CdBr2]. The X‐ray crystal structures of [L1CdBr2]2, [L2CdBr2]2 and [L3CdBr2]2 reveal a bromo‐bridged dimeric species with crystallographic inversion symmetry. Conversely, [L4CdBr2] and [L5CdBr2] exist as monomeric complexes, presumably due to the steric hindrance between the methyl substituents of the two pyrazole groups in the ligand and cadmium centre for [L4CdBr2], and crowding around the cadmium metal by methyl substituents on the aniline residue in the ligand for [L5CdBr2]. The geometry at each Cd(II) centre for [L1CdBr2]2, [L2CdBr2]2 and [L3CdBr2]2 is best described as a distorted trigonal bipyramid. A distorted trigonal bipyramid is achieved in [L4CdBr2] by coordinative interaction of the nitrogen atom of the aniline unit and the cadmium atom with a σ plane of symmetry, based on the bond length of Cd―Naniline (2.759(7) Å). [L5CdBr2] exists with a distorted tetrahedral geometry involving non‐coordination of the nitrogen atom of aniline and the Cd centre, resulting in the formation of an eight‐membered chelate ring. The catalytic activity of monomeric, five‐coordinated [L4CdBr2] in the polymerization of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) at 60°C resulted in a higher molecular weight and a narrower polydispersity index (PDI) than those obtained with dimeric [LnCdBr2]2 (Ln = L1, L2, L3) or monomeric tetrahedral [L5CdBr2]. Copyright © 2014 John Wiley & Sons, Ltd.

Spirocyclohexadienones: XIII. Reactions of schiff bases with enamines derived from 3,4-dihydroisoquinoline and with spiro[naphthalene-1,3′-pyrrol]-4-one

Addition of 1,3,3-trimethyl-3,4-dihydroisoquinolines to N-benzylideneanilines gives substituted N-[2-(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)-1-phenylethyl]anilines, whereas 2′,5′,5′-trimethyl-4′,5′-dihydro-4H-spiro[naphthalene-1,3′-pyrrol]-4-one reacts with N-benzylideneanilines along two pathways involving cyclization to substituted 2,3,3a,4,10,11-hexahydrobenzo[f]pyrrolo[2,3-d]quinolin-5(1H)-ones or elimination of the aniline residue with formation of substituted 5′,5′-trimethyl-2-styryl-4′,5′-dihydro-4H-spiro[naphthalene-1,3′-pyrrol]-4-ones.

A second monoclinic polymorph for 3-amino-1-(4-methoxyphenyl)-9,10-dihydrophenanthrene-2,4-dicarbonitrile

The title compound, C23H17N3O, has been previously described in a monoclinic P21/c polymorph with Z = 4 [Asiri, Al-Youbi, Faidallah, Ng & Tiekink (2011). Acta Cryst. E67, o2449]. In the new monoclinic P21/n form, with Z = 8, there are two independent mol­ecules, A and B, in the asymmetric unit. In both mol­ecules, the cyclo­hexa-1,3-diene ring has a screw-boat conformation, whereas it is a distorted half-chair in the original polymorph. There is a fold in each mol­ecule, as indicated by the dihedral angle between the benzene rings of the 1,2-dihydro­naphthalene and aniline residues of 33.19 (10)° (mol­ecule A) and 30.6 (10)° (mol­ecule B). The meth­oxy­benzene ring is twisted out of the plane of the aniline residue to which it is connected [dihedral angles = 49.22 (10) and 73.27 (10)°, in A and B respectively]. In the crystal, the two independent mol­ecules self-associate via N—H⋯N hydrogen bonds, generating a 12-membered {⋯HNC3N}2 synthon. These are connected into a supra­molecular tape in the (-101) plane by N—H⋯O(meth­oxy) inter­actions. In the P21/c polymorph, supra­molecular layers are formed by N—H⋯N and N—H⋯O inter­actions.

Substituent effects upon rates of deamination and base strengths of substituted N-tritylamines

Substituted N-tritylamines undergo deamination in aqueous acidic solution containing organic cosolvents, and follow a pseudo first-order specific acid-catalysis rate law (kobs = k0 + kH[H3O+]); the products are the corresponding trityl alcohols in equilibrium with the trityl carbenium ions, and ammonium ions. The change from 4,4′-dimethoxy- to 4,4′,4″-trimethoxy-tritylamine increases reactivity by a factor of about 30 in both k0 and kH, but N-alkyl and N-aryl groups have much greater effects (ca. 106 for both k0 and kH for 4,4′-dimethoxytritylamine) which are largely independent of the nature of the N-alkyl and N-aryl groups. The anions of the catalytic strong acids (perchlorate, chloride, bromide, and nitrate) have only small effects as also does the concentration of acetonitrile as cosolvent; ethanoic acid as cosolvent is mildly rate-enhancing. Substituents in the aniline residue of N-(4,4′-dimethoxytrityl)anilines have virtually no effect upon either k0 or kH (ρ = 0 for both). The results are interpreted by a mechanism involving a pre-equilibrium heterolysis of the (substituted) tritylammonium ion to give an ion–molecule pair which may undergo diffusional or acid-catalysed dissociation before the (substituted) trityl cation undergoes equilibrium nucleophilic capture by water. Base strengths of some substituted N-tritylamines have been measured; the substituted N-trityl group causes all amines (aliphatic and aromatic) to be comparably strongly basic (pKBH+ca. 9).

Preparation and diazo-coupling reaction of the pendant spacer-separated aniline residue based on a polyoxetane network

Polyoxetane networks anchoring the pendant spacer-separated aniline residue were prepared in good yield by a BF 3-initiated ring-opening polymerization of the corresponding succinyl-protected oxetane monomer with a bisoxetane, as a crosslinking agent, followed by alkaline hydrolysis of the crosslinked product. Diazo-coupling reactions of the pendant aniline residue were examined with phenol and resorcinol, and the formation of desired polymers was confirmed by comparing the structures between the polymer products and the authentic polymers by IR and 1H-NMR spectroscopy.

Separation of Ring Polar and Resonance Effects on the Rate and Equilibrium Constants for Methoxide Ion-Promoted Addition of Methanol to N-Benzylideneanilines Substituted at the Benzylidene Moiety

Rate and equilibrium constants for the title reaction (α-amino ether formation) at 25 o C in methanol are reported for (16) N-benzylideneani- lines (BAs) substituted at the benzaldehyde moiety. In contrast to a previous report dealing with BAs substituted at the aniline residue, it is shown that an uncatalyzed pathway competes with the methoxide ion- catalyzed reaction, these two processes corresponding to rate-limiting attachment of the lyate ion to the C=N bond of iminium ion and free imine, respectively. For the latter reaction pathway, the lifetimes of the amide-ion intermediates are long enough to allow a stepwise mecha- nism

End-functionalized polymers by living cationic polymerization

End-functionalized poly(isobutyl vinyl ether) (2) with a terminal amine, carboxylic acid, or ester group was prepared by quenching the HI/I2-initiated living polymer ends with ring-substituted anilines (H2N-C6H4-X, p or m; X = NH2, COOH, COOC2H5). The living polymerization of isobutyl vinyl ether and the subsequent end-capping reaction were carried out at −15°C in methylene chloride. The resulting polymers exhibited a narrow molecular weight distribution $$(\bar M_W /\bar M_n = 1.1 - 1.2)$$ and carried one terminal function (aniline residue) per chain, according to 1H NMR structural analysis.

Bromine oxidation of N-(3 or 4-substituted phenyl)-N'-3-phenylpropenoylthioureas

Bromine oxidation of N-(3 or 4-substituted phenyl)-N'-3-phenylpropenoylthioureas in chloroform afforded either derivatives of benzylidenethiazoline or benzothiazole depending on the structure of the aniline residue. The structure of the title products was proved by elemental analysis, IR, 1H NMR and 13C NMR spectral data.

ChemInform Abstract: REACTION OF BENZO‐1,2,3‐DITHIAZOLIUM SALTS WITH AROMATIC AMINES

AbstractDie aus den o‐Aminothiophenolen (I) durch Umsetzung mit Thionylchlorid hergestellten Benzodithiazoliumsalze (II) reagieren mit Anilin (III) in Eisessig unter Substitution von 6‐ständigen Chlor‐ oder Methoxyresten zu den Phenylaminobenzodithiazoliumsalzen (IV), wobei die Substitution des Methoxyrestes langsamer verläuft als die des Chlors.

Reaction of benzo-1,2,3-dithiazolium salts with aromatic amines

The character of a displaceable group depends substantially on the rate of reaction of substituted 6-chloro and 6-methoxy derivatives of benzo-1,2,3-dithiazolium salts, which gives the corresponding 6-phenylaminobenzo-1,2,3-dithiazolium salts. In 4,6-disubstituted benzo-1,2,3-dithiazolium salts, an aniline residue displaces only the substituent in the 6 position.

Vinylamine—XVI : Untersuchung der substituentenabhängigkeit der imin-enamin-tautomerie an β-aryl-β-methyl-vinyl-N-aryl-aminen

The equilibrium position of the imine-enamine-tautomeric compounds 2–4 has been determined. The substituent dependence on R 1 can be described by σ-values only in the case of m-substituted aniline derivatives. With p-derivatives deviations are observed, which can be accounted for by use of a-M-values. Therefore it is possible to describe homogeneously all the imine-enamine-tautomeric systems 1–4 investigated. The cis-trans-equilibrium of the enamine tautomer which overlays the imine-enamine-tautomerism is nearly independent of the substituent in the aniline residue.