Acridine Series Research Articles

Thermal stabilisation of the short DNA duplexes by acridine-4-carboxamide derivatives.

The short oligodeoxynucleotide (ODN) probes are suitable for good discrimination of point mutations. However, the probes suffer from low melting temperatures. In this work, the strategy of using acridine-4-carboxamide intercalators to improve thermal stabilisation is investigated. The study of large series of acridines revealed that optimal stabilisation is achieved upon decoration of acridine by secondary carboxamide carrying sterically not demanding basic function bound through a two-carbon linker. Two highly active intercalators were attached to short probes (13 or 18 bases; designed as a part of HFE gene) by click chemistry into positions 7 and/or 13 and proved to increase the melting temperate (Tm) of the duplex by almost 8°C for the best combination. The acridines interact with both single- and double-stranded DNAs with substantially preferred interaction for the latter. The study of interaction suggested higher affinity of the acridines toward the GC- than AT-rich sequences. Good discrimination of two point mutations was shown in practical application with HFE gene (wild type, H63D C > G and S65C A > C mutations). Acridine itself can also serve as a fluorophore and also allows discrimination of the fully matched sequences from those with point mutations in probes labelled only with acridine.

Synthesis of acridine, bisacridine and quinoline derivatives with 1,2-azolic, pyridine and ferrocene fragments. Vestsi Natsyyanal’nai akademii navuk Belarusi

Natural and synthetic derivatives of acridine and pyrimidoquinoline series are of considerable interest for study as antiviral, antitumor, antibacterial, antiparasitic agents; they are also useful in the treatment of Alzheimer’s disease. The combination of acridine and pyrimidoquinoline cycles with other pharmacophore groups can lead to a synergistic effect of their properties, the appearance of new types of biological activity, as well as a reducing of the severity of side effects. The synthesis of new derivatives of 8,9,10,12-tetrahydrobenzo[a]acridin-11(7H)-one and 10,12-dihydrobenzo[ f ] pyrimido [4,5- b ] quinoline-9,11 (7H, 8H)-dione containing isoxazole, isothiazole heterocycles, ferrocene fragment, as well as nicotinic and isonicotinic acid residues covalently attached via ester groups to different positions of the aromatic nucleus, is described. A three-component cascade condensation of aromatic amines, aldehydes and cyclic β —dicarbonyl compounds was carried out by refluxing in butanol. The heat effects of the cyclization reaction have been determined using the DFT / B3LYP1 / MIDI method. The cytotoxic activity of the synthesized compounds was assessed on four different cancer cell lines (RKO, COLO320, LS174T, SW480).

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

AbstractThe review covers the results of studies published in the literature on the synthesis of spiro‐linked heterocycles of the indole, quinoline, benzoxazine, benzothiazine, indenoquinoxaline, pyridopyrimidine, and acridine series. Possible approaches to the synthesis of spirocycles through a sequence of well‐known Knoevenagel, Michael reactions, deamination cyclization of 1,2‐dicarbonyl, CH‐acid compounds, direct cycloaddition of activated olefins to isatins, 3‐alkylideneindoles, 2‐oxindoles, in situ generated azomethine ylides, indenoquinoxalines are analyzed. Attention is drawn to approaches to the preparation of spiro‐fused compounds using reactions of intra‐ and intermolecular dearomatization of indoles. Recent advances in the synthesis of spiro‐linked benzo heterocycles from derivatives of 2‐olefin substituted anilines are summarized. The examples of the synthesis of spiro‐fused heterocycles by means of metal complexes catalyzed decomposition of diazo compounds are given. Some syntheses of biologically active representatives are shown, as well as the use of transformations of spiroheterocycles in the preparation of other heterocycles.

Synthesis of N-Arylquinone Diimine Derivatives of 2H-Benzimidazo[2,1-e]acridine and Their Reactions with Aromatic Amines

Oxidative coupling of 6,7,8,9,9a,10,11,12,13,14-decahydro-5H-benzimidazo[2,1-e]acridine with reagents containing a primary aromatic amino group forms p-quinone diimines of the 2H-benzimidazo[2,1-e]-acridine series. The subsequent acid-activated 1,4-nucleophilic addition reaction of the products with the same reagents followed by autooxidation gives rise to 3-arylamino-substituted quinone diimines of the specified series.

Halogen-Substituted Acridines as Highly Effective Corrosion Inhibitors for Mild Steel in Acid Medium

A series of acridines were designed and synthesized for the development of effective inhibitors for mild steel corrosion in 1 M HCl solution, in which the halogen-substituted acridines showed better inhibitive performance than the nonhalogen-substituted acridines. The corrosion protection properties of the halogen-substituted acridines, including 2-chloro-9-phenylacridine (CPA), 2-chloro-9-(2-fluorophenyl)acridine (CFPA), and 2-bromo-9-(2-fluorophenyl)acridine (BFPA), were further investigated using weight loss test and electrochemical techniques. The results indicated the halogen-substituted acridines have excellent inhibitiion performance, and these acridines act as mixed-type inhibitors with predominant cathodic effectiveness. Adsorption of acridines on a mild steel surface obeyed the Langmuir adsorption isotherm. The adsorption of the inhibitor molecules on the steel surface was further supported by scanning electron microscopy (SEM), scanning electrochemical microscopy (SECM), and FTIR spectroscopy. ...

Palladium-Catalyzed Regioselective Alkoxylation via C-H Bond Activation in the Dihydrobenzo[c]acridine Series

5,6-Dihydrobenzo[c]acridine belongs to the large aza-polycyclic compound family. Such molecules are not fully planar due to the presence of a partially hydrogenated ring. This paper describes the first Pd-catalyzed alkoxylation via C-H bond activation of variously substituted 5,6-dihydrobenzo[c]acridines. We determined suitable conditions to promote the selective formation of C-O bonds using 10% Pd(OAc)2, PhI(OAc)2 (2 eq.) and MeOH as the best combination of oxidant and solvent, respectively. Under these conditions, 5,6-dihydrobenzo[c]acridines bearing substituents at both rings A and D were successfully functionalized, giving access to polysubstitutited acridine motifs.

DNA interaction of bromomethyl-substituted acridines

A series of acridines with bifunctional substituents was synthesized with the dual properties of DNA alkylation and intercalation. 4,5-Bis(bromomethyl)acridine (1) was previously reported to crosslink and intercalate with DNA. In this study, 1,8-bis(bromomethyl)acridine (2) and 2,7-bis(bromomethyl)acridine (3), monofunctional 2-(bromomethyl)-7-methylacridine (4) and 2,7-dimethylacridine (5) were synthesized, and their crosslinking and intercalative activities were investigated to assess the reactivity of bromomethyl acridines with DNA. Interstrand crosslinking activity was similar among the three bis(bromomethyl)acridines. The acridines exhibited intercalation activity for calf thymus DNA as follows: 3 > 4 > 2 = 1 >>> 5. Intracellular DNA-crosslinking and DNA-intercalating activities were evaluated using the Ames assay. 4 was mutagenic in Salmonella typhimurium TA100 and TA98, indicating that the bromomethyl group alkylated DNA bases. All three bis(bromomethyl)acridines were mutagenic in S. typhimurium TA92 and TA94, which can detect intracellular crosslinking DNA damage, whereas 5 was not mutagenic in these strains. The results showed that the bis(bromomethyl)acridines crosslinked DNA and intercalated between DNA bases, and 3 exhibited the highest crosslinking and intercalating activity.

Design, synthesis and biological evaluation of 4-amidobenzimidazole acridine derivatives as dual PARP and Topo inhibitors for cancer therapy

PARP-1 could repair the DNA damages induced by Topo inhibitors, therefore inhibiting Topo and PARP-1 simultaneously might be able to overcome resistance and improve outcomes. In this study a series of 4-amidobenzimidazole acridines were designed and synthesized as dual Topo and PARP-1 inhibitors. Compound 11l displayed good inhibitory activities against Topo and PARP-1, as well as significantly inhibited cancer cells proliferation. Further mechanistic evaluations indicated that 11l treatment in MCF-7 cells induced accumulated DNA double-strand breaks, prompted remarkable apoptosis, and caused prominent G0/G1 cell cycle arrest. Moreover, 11l greatly suppressed tumor growth in mice, and displayed favorable metabolic properties in liver microsomes. Our study suggested that single agents inhibiting Topo and PARP concurrently might be an alternative for cancer therapy and 11l represented a potential lead compound for development of antitumor agents.

Infrared spectroscopy of matrix-isolated neutral polycyclic aromatic nitrogen heterocycles: The acridine series

The matrix-isolated, mid-infrared spectra of seven acridine-based polycyclic aromatic nitrogen heterocycles (PANHs) have been measured and compared to their non-nitrogen containing parent molecule. The acridine species investigated include acridine, benz[a]acridine, benz[c]acridine, dibenz[a,j]acridine, dibenz[c,h]acridine, dibenz[a,h]acridine and dibenz[a,c]acridine. The previously reported results for 1 and 2-azabenz[a]anthracenes are included for comparison. The experimentally determined band frequencies and intensities are compared with their B3LYP/6–31G(d) values. The overall agreement between experimental and theoretical values is good and in line with our previous investigations. Shifts, typically to the blue, are noted for the C–H out-of-plane (CHoop) motions upon insertion of a nitrogen atom. The formation of a bay region upon addition of additional benzene rings to the anthracene/acridine structure splits the solo hydrogen motions into a bay region solo and an external solo hydrogen, with the bay region solo hydrogen coupling to the quartet hydrogen motions and the external solo hydrogen coupling with the duo hydrogen motions resulting in an extreme decrease in intensity for the CHoop solo hydrogen band when the external hydrogen is replaced by a nitrogen atom. The C–C and C–H in-plane region of this acridine series exhibits the characteristic two fold increase in intensity, noted previously for PANHs. The strong ≈1400cm−1 band, which was identified in the previous PANH study, is noted in several molecular species as well as another strong PANH feature between 1480 and 1515cm−1 for several molecules. The presence of these strong bands appear to be primarily responsible for the two-fold increase in the C-H in-plane region's (1100–1600cm−1) intensity. The C–H stretching region can be characterized by contributions from the solo (bay or external), duo and quartet hydrogens, similar to what was observed in the dibenzopolyacene compounds.

ChemInform Abstract: New Series of Acridines and Phenanthrolines: Synthesis and Characterization.

Abstract New series of acridines and phenanthrolines have been prepared from β-chlorovinyl aldehydes and various aniline derivatives allowing the installation of valuable substituents, such as ketone, nitro or amino groups at the heterocyclic core. X-ray analyses confirmed the structures of acridines and phenanthrolines as well as the presence of partially hydrogenated rings and their crucial impact on the overall shape of the acridine-based architectures. 1H NMR revealed the helical behaviour of several acridine motives. Comparison of UV data between architectures and influence of number of partially hydrogenated rings is also described.

Novel trisubstituted acridines as human telomeric quadruplex binding ligands

A novel series of trisubstituted acridines were synthesized with the aim of mimicking the effects of BRACO19. These compounds were synthesized by modifying the molecular structure of BRACO19 at positions 3 and 6 with heteroacyclic moieties. All of the derivatives presented in the study exhibited stabilizing effects on the human telomeric DNA quadruplex. UV–vis spectroscopy, circular dichroism, linear dichroism and viscosimetry were used in order to study the nature of the DNA binding in more detail. The results show that all of the novel derivatives were able to fold the single-stranded DNA sequences into antiparallel G-quadruplex structures, with derivative 15 exhibiting the highest stabilizing capability. Cell cycle analysis revealed that a primary trend of the “braco”-like derivatives was to arrest the cells in the S- and G2M-phases of the cell cycle within the first 72h, with derivative 13 and BRACO19 proving particularly effective in suppressing cell proliferation. All studies derivatives were less toxic to human fibroblast cell line in comparison with HT 29 cancer cell line.

New series of acridines and phenanthrolines: synthesis and characterization

New series of acridines and phenanthrolines have been prepared from β-chlorovinyl aldehydes and various aniline derivatives allowing the installation of valuable substituents, such as ketone, nitro or amino groups at the heterocyclic core. X-ray analyses confirmed the structures of acridines and phenanthrolines as well as the presence of partially hydrogenated rings and their crucial impact on the overall shape of the acridine-based architectures. 1H NMR revealed the helical behaviour of several acridine motives. Comparison of UV data between architectures and influence of number of partially hydrogenated rings is also described.

Pd(II)-Catalyzed One-Pot, Three-Step Route for the Synthesis of Unsymmetrical Acridines

Unsymmetric acridines are synthesized via a one-pot amination/cyclization/aromatization reaction for the first time. With Pd(OAc)2-X-Phos as the catalyst, a series of unsymmetric acridines are obtained in moderate to excellent yields (up to 99% yield). Meanwhile, the diphenylamine intermediate could be isolated, which is evidence of the domino process.

Structure–activity relationship study of beta-carboline derivatives as haspin kinase inhibitors

Haspin is a serine/threonine kinase that phosphorylates Thr-3 of histone H3 in mitosis that has emerged as a possible cancer therapeutic target. High throughput screening of approximately 140,000 compounds identified the beta-carbolines harmine and harmol as moderately potent haspin kinase inhibitors. Based on information obtained from a structure–activity relationship study previously conducted for an acridine series of haspin inhibitors in conjunction with in silico docking using a recently disclosed crystal structure of the kinase, harmine analogs were designed that resulted in significantly increased haspin kinase inhibitory potency. The harmine derivatives also demonstrated less activity towards DYRK2 compared to the acridine series. In vitro mouse liver microsome stability and kinase profiling of a representative member of the harmine series (42, LDN-211898) are also presented.

Atomistic simulations of materials for optical chemical sensors: DFT-D calculations of molecular interactions between gas-phase analyte molecules and simple substrate models

The structures of complexes of some small molecules (formaldehyde, acetaldehyde, ammonia, methylamine, methanol, ethanol, acetone, benzene, acetonitrile, ethyl acetate, chloroform, and tetrahydrofuran, considered as possible analytes) with ethylbenzene and silanol (C(6)H(5)C(2)H(5) and SiH(3)OH, considered as models of polystyrene and silica gel substrates) and with acridine (C(13)H(9)N, considered as a model of an indicator dye molecule of the acridine series) and the corresponding interaction energies have been calculated using the DFT-D approximation. The PBE exchange-correlation potential was used in the calculations. The structures of complexes between the analyte and the substrate were determined by optimizing their ground-state geometry using the SVP split-valence double-zeta plus polarization basis set. The complex formation energies were refined by single-point calculations at the calculated equilibrium geometries using the sufficiently large triple-zeta TZVPP basis set. The calculated interaction energies are used to assess the possibility of using dyes of the acridine series adsorbed on a polystyrene or silica substrate for detecting the small molecules listed above.

ChemInform Abstract: Application of Phase-Transfer Catalysis in Acridine Series. Part 6. Preparation of Some 9-Vinylacridine Derivatives.

ChemInform Abstract: Application of Phase-Transfer Catalysis in Acridine Series. Part 6. Preparation of Some 9-Vinylacridine Derivatives.

ChemInform Abstract: Synthesis of 1,3-Diynes in the Purine, Pyrimidine, 1,3,5-Triazine and Acridine Series.

Abstract A range of conjugated 1,3-diynes, R1CCCCR2, has been prepared that incorporate the following heteroaromatic units as head groups of the substituents R1 and/or R2: pyrimidinyl, purinyl, 2,4-diamino-1,3,5-triazinyl and acridinyl. Compounds containing the first three groups as terminal heterocyclic substituents in both R1 and R2 are bonded through methylene linkers {(CH2)n, n=1, 4 or 9} to the 1,3-diyne; also reported are amphiphilic species with R2=n-C10H21 and a single heteroaromatic head group in chain R1. Compounds in the acridine series are also amphiphiles and contain quaternised 1′-(9-acridinylamino)- and 1′-(6-chloro-2-methoxyacridinylamino)- terminal substituents linked by PEG and methylene units to the diyne function. The new diynes have been synthesised by oxidative coupling of the corresponding ω-heteroaromatic functionalised 1-alkyne or by transformation of terminal groups on preformed diynes.

Structure–activity relationship study of acridine analogs as haspin and DYRK2 kinase inhibitors

Haspin is a serine/threonine kinase required for completion of normal mitosis that is highly expressed during cell proliferation, including in a number of neoplasms. Consequently, it has emerged as a potential therapeutic target in oncology. A high throughput screen of approximately 140,000 compounds identified an acridine analog as a potent haspin kinase inhibitor. Profiling against a panel of 270 kinases revealed that the compound also exhibited potent inhibitory activity for DYRK2, another serine/threonine kinase. An optimization study of the acridine series revealed that the structure–activity relationship (SAR) of the acridine series for haspin and DYRK2 inhibition had many similarities. However, several structural differences were noted that allowed generation of a potent haspin kinase inhibitor (33, IC50 <60nM) with 180-fold selectivity over DYRK2. In addition, a moderately potent DYRK2 inhibitor (41, IC50 <400nM) with a 5.4-fold selectivity over haspin was also identified.

Synthesis and evaluation of fused bispyrimidinoacridines as novel pentacyclic analogues of quadruplex-binder BRACO-19

The present article reports on the design and the synthesis of a series of mono- and bis-pyrimidinoacridines and their evaluation as a novel family of quadruplex-binders. It is shown that bispyrimidinoacridines represent an interesting compromise between easy synthetic access and efficiency in terms of quadruplex interaction (both affinic and selective), as judged by G4-FID assay and molecular modelling. The present study also highlights that control of the pi-stacking interactions taking place between the ligand and the accessible G-tetrad of a quadruplex-DNA is indeed essential for good recognition but not exclusively (key role of direct and water-mediated H-bonds). The introduction of additional amino side chains, valuable in the acridine series, results here in steric perturbations of the ligand/quadruplex recognition and lowers the quadruplex/duplex selectivity.

Interactions of sulfur-containing acridine ligands with DNA by ESI-MS.

The alkylating proficiency of sulfur-containing mustards may be increased by using an acridine moiety to guide the sulfur mustard to its cellular target. In this study, the interactions of a new series of sulfur-containing acridine ligands, some that also function as alkylating mustards, with DNA were evaluated by electrospray ionization mass spectrometry (ESI-MS). Relative binding affinities were estimated from the ESI-MS data based on the fraction of bound DNA for DNA/acridine mixtures. The extent of binding observed for the series of sulfur-containing acridines was similar, presumably because the intercalating acridine moiety was identical. Upon infrared multi-photon dissociation (IRMPD) of the resulting oligonucleotide/sulfur-containing acridine complexes, ejection of the ligand was the dominant pathway for most of the complexes. However, for AS4, an acridine sulfide mustard, and AN1, an acridine nitrogen mustard, strand separation with the ligand remaining on one of the single strands was observed. At higher irradiation times, a variety of sequence ions were observed, some retaining the AS4/AN1 ligand, which was indicative of covalent binding.