Synthesis and In Vitro Cytotoxicity of the 4-(Halogenoanilino)-6-bromoquinazolines and Their 6-(4-Fluorophenyl) Substituted Derivatives as Potential Inhibitors of Epidermal Growth Factor Receptor Tyrosine Kinase.

Series of the 2-unsubstituted and 2-(4-chlorophenyl)-substituted 4-anilino-6-bromoquinazolines and their 6-(4-fluorophenyl)-substituted derivatives were evaluated for in vitro cytotoxicity against MCF-7 and HeLa cells. The 2-unsubstituted 4-anilino-6-bromoquinazolines lacked activity, whereas most of their 2-(4-chlorophenyl) substituted derivatives were found to exhibit significant cytotoxicity and selectivity against HeLa cells. Replacement of bromine with 4-fluorophenyl group for the 2-unsubstituted 4-anilinoquinazolines resulted in superior activity against HeLa cells compared to Gefitinib. The presence of a 4-fluorophenyl group in the 2-(4-chlorophenyl) substituted derivatives led to increased cytotoxicity against HeLa cells, except for the 3-chloroanilino derivative. The most active compounds, namely, 3g, 3l, and 4l, were found to exhibit a moderate to significant inhibitory effect against epidermal growth factor receptor tyrosine kinase (EGFR-TK). The EGFR molecular docking model suggested that these compounds are nicely bound to the region of EGFR.

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides.

The structures of the mono- and the dihalogenated N-unsubstituted 2-aminobenzamides were characterized by means of the spectroscopic (¹H-NMR, UV-Vis, FT-IR, and FT-Raman) and X-ray crystallographic techniques complemented with a density functional theory (DFT) method. The hindered rotation of the C(O)-NH2 single bond resulted in non-equivalence of the amide protons and therefore two distinct resonances of different chemical shift values in the ¹H-NMR spectra of these compounds were observed. 2-Amino-5-bromobenzamide (ABB) as a model confirmed the presence of strong intramolecular hydrogen bonds between oxygen and the amine hydrogen. However, intramolecular hydrogen bonding between the carbonyl oxygen and the amine protons was not observed in the solution phase due to a rapid exchange of these two protons with the solvent and fast rotation of the Ar-NH2 single bond. XRD also revealed the ability of the amide unit of these compounds to function as a hydrogen bond donor and acceptor simultaneously to form strong intermolecular hydrogen bonding between oxygen of one molecule and the NH moiety of the amine or amide group of the other molecule and between the amine nitrogen and the amide hydrogen of different molecules. DFT calculations using the B3LYP/6-311++G(d,p) basis set revealed that the conformer (A) with oxygen and 2-amine on the same side predominates possibly due to the formation of a six-membered intramolecular ring, which is assisted by hydrogen bonding as observed in the single crystal XRD structure.

Synthesis and In Vitro Cytotoxic Properties of Polycarbo-Substituted 4-(Arylamino)quinazolines.

Herein, we describe the synthesis of novel unsymmetrical polycarbo-substituted 4-anilinoquinazolines derived from the 2-aryl-6-bromo-8-iodoquinazolines via one-pot three-step reaction sequences involving initial amination and subsequent double cross-coupling (bis-Suzuki, Sonogashira/Stille or Sonogashira/Suzuki-Miyaura) reactions with different cross coupling partners for the two carbon-carbon bond formation steps. The 4-anilinoquinazolines were evaluated for potential cytotoxicity against three cancer cell lines, namely, human breast adenocarcinoma (MCF-7) cells, human cervical cancer (HeLa) and human lung cancer (A549) cells. The most active compounds, 2b, 2c, 3c, 4a, 4c and 5a, were found to be more selective against the MCF-7 and HeLa cell lines than the human lung carcinoma (A549) cells. We selected compounds 2c, 3c and 7a as representatives for further evaluation for potential to induce apoptosis and/or necrotic properties in the three cancer cell lines. Compound 2c induced apoptosis of MCF-7 cells through cell membrane alteration. Treatment of Hela and A549 cell lines with compounds 3c and 7a, respectively, led to caspase-3 activation in both cell lines. Compound 3c, on the other hand, caused more necrosis than apoptosis induction in the membrane alteration assay.

Novel Polycarbo-Substituted Imidazo[1,2-c]quinazolines: Synthesis and Cytotoxicity Study.

Amination of the 2-aryl-6-bromo-4-chloro-8-iodoquinazolines with 2-aminoethanol followed by acid-promoted cyclodehydration of the incipient 2-((6,8-dihalo-2-phenylquinazolin-4-yl)amino)ethanols afforded the corresponding novel 5-aryl-9-bromo-7-iodo-2,3-dihydro-2H-imidazo[1,2-c]quinazolines. The latter were, in turn, subjected to sequential (Sonogashira and Suzuki-Miyaura) and one-pot two-step (Sonogashira/Stille) cross-coupling reactions to afford diversely functionalized polycarbo-substituted 2H-imidazo[1,2-c]quinazolines. The imidazoquinazolines were screened for in vitro cytotoxicity against human breast adenocarcinoma (MCF-7) cells and human cervical cancer (HeLa) cells.

Synthesis, Biological Evaluation and Molecular Docking Studies of 6-Aryl-2-Styrylquinazolin-4(3H)-Ones.

Suzuki-Miyaura cross-coupling of 6-bromo-2-styrylquinazolin-4(3H)-ones with arylboronic acids afforded a series of novel 6-aryl-2-styrylquinazolin-4(3H)-ones. These compounds were evaluated for potential anticancer properties against the human renal (TK-10), melanoma (UACC-62) and breast cancer (MCF-7) cell lines. Their antimicrobial properties were also evaluated against six Gram-positive and four Gram-negative bacteria, as well as two strains of fungi. Molecular docking studies (in silico) were conducted on compounds 5a, b, d and 6a, b, d-f to recognize the hypothetical binding motif of the title compounds within the active site of the dihydrofolate reductase and thymidylate synthase enzymes.

Synthesis and Photophysical Properties of Polycarbo-Substituted Quinazolines Derived from the 2-Aryl-4-chloro-6-iodoquinazolines.

The reactivity of the 2-aryl-4-chloro-6-iodoquinazolines towards palladium catalyzed sequential (Sonogashira/Suzuki-Miyaura) and one-pot two-step cross-coupling (bis-Sonogashira, and successive Sonogashira/Stille) reactions to afford novel unsymmetrical polycarbo-substituted quinazolines has been evaluated. In contrast to the chloro-bromo substituted quinazolines in which selectivity has been previously found to generally favor substitution at the more activated C(4)-Cl bond over the weaker Csp(2)-Br bond, substitution in the case of the chloro-iodo derivatives favors cross-coupling through the intrinsically more reactive Csp(2)-I bond. The electronic absorption and emission properties of the prepared 2,3-diaryl-6-(phenylethynyl)quinazolines were studied in solvents of different polarity (dichloromethane, toluene, DMF, methanol) and CH2Cl2-TFA mixture using UV-Vis and emission spectroscopic techniques complemented with density functional theory method to establish the effect of substituents on intramolecular charge transfer properties.

Novel polycarbo-substituted alkyl (thieno[3,2-c]quinoline)-2-carboxylates: synthesis and cytotoxicity studies.

Direct one-pot base-promoted conjugate addition-elimination of 6,8-dibromo-4-chloroquinoline-3-carbaldehyde with methyl mercaptoacetate and subsequent cyclization afforded methyl [(6,8-dibromothieno[3,2-c]quinoline)]-2-carboxylate. The latter undergoes Suzuki-Miyaura cross-coupling with arylboronic acids to yield exclusively the corresponding alkyl [(6,8-diarylthieno[3,2-c]quinoline)]-2-carboxylates,. The cytotoxicity of the prepared compounds was evaluated against the human breast cancer cell line MCF-7 using the MTT assay. The effects of compounds 2, 3c and 4d on cell kinetics were further determined using the xCELLigence Real Time Cell Analysis (RTCA) system. In both the MTT assay and Real Time Cell Analysis, the compounds inhibited cancer cell growth in a dose- and time-dependent manner. Furthermore, on the basis of the calculated LC50 values, the compounds compared favourably with nocodazole, a well-established anticancer drug.

Advances in metal-catalyzed cross-coupling reactions of halogenated quinazolinones and their quinazoline derivatives.

Halogenated quinazolinones and quinazolines are versatile synthetic intermediates for the metal-catalyzed carbon-carbon bond formation reactions such as the Kumada, Stille, Negishi, Sonogashira, Suzuki-Miyaura and Heck cross-coupling reactions or carbon-heteroatom bond formation via the Buchwald-Hartwig cross-coupling to yield novel polysubstituted derivatives. This review presents an overview of the application of these methods on halogenated quinazolin-4-ones and their quinazolines to generate novel polysubstituted derivatives.

Synthesis and photophysical property studies of the 2,6,8-triaryl-4-(phenylethynyl)quinazolines.

The 2-aryl-6,8-dibromo-4-chloroquinazolines derived from the 2-aryl-6,8-dibromoquinazolin-4(3H)-ones were subjected to the Sonogashira cross-coupling with terminal acetylenes at room temperature to afford novel 2-aryl-6,8-dibromo-4-(alkynyl)quinazoline derivatives. Further transformation of the 2-aryl-6,8-dibromo-4-(phenylethynyl)quinazolines via Suzuki-Miyaura cross-coupling with arylboronic acids occurred without selectivity to afford the corresponding 2,6,8-triaryl-4-(phenylethynyl)quinazolines. The absorption and emission properties of these polysubstituted quinazolines were also determined.

4,6,8-Triarylquinoline-3-carbaldehyde derivatives: synthesis and photophysical properties.

Palladium catalyzed Suzuki-Miyaura cross-coupling of 6,8-dibromo-4-chloroquinoline-3-carbaldehyde with arylboronic and arylvinylboronic acid derivatives in the presence of potassium carbonate in aqueous dioxane afforded the corresponding 4,6,8-triarylquinoline-3-carbaldehydes, exclusively. These products were transformed into 4,6,8-triaryl-3-(4-fluorophenyl)amino)-N-(quinolin-3-yl)methylenes and their 4,6,8-triaryl-quinoline-3-methanol derivatives. The absorption and emission spectra were measured for the 4,6,8-triarylquinoline-3-carbaldehydes and their derivatives in selected solvents of different polarity.

Synthesis and photophysical properties of 2-aryl-6,8-bis(arylethenyl)-4-methoxyquinolines.

Iodine-methanol mediated oxidative-aromatization of 2-aryl-6,8-dibromo-2,3-dihydroquinolin-4(1H)-ones afforded the corresponding 2-aryl-6,8-dibromo-4-methoxy-quinolines in high yield and purity. The isomeric 1-(2-amino-3,5-dibromophenyl)-3-aryl-2-propen-1-ones reacted with iodine in methanol afford in a single pot operation the corresponding 2-aryl-6,8-dibromo-4-methoxyquinoline (major) and 2-aryl-6,8-dibromoquinolin-4(1H)-one (minor) products that were separated in sequence by column chromatography on silica gel. Suzuki-Miyaura cross-coupling of the 6,8-dibromo-4-methoxyquinoline derivatives with excess arylvinylboronic acids afforded the corresponding 2-aryl-6,8-bis(2-arylethenyl)-4-methoxyquinolines. The absorption and fluorescence properties of these compounds were also determined.

Direct one-pot synthesis of primary 4-amino-2,3-diaryl-quinolines via Suzuki-Miyaura cross-coupling of 2-aryl-4-azido-3-iodoquinolines with arylboronic acids.

Palladium-catalyzed Suzuki-Miyaura cross-coupling of 2-aryl-4-azido-3-iodo-quinolines with arylboronic acids afforded the corresponding primary 4-amino-2,3-diarylquinolines in a single-pot operation along with symmetrical biaryls and traces of the 2,3-diaryl-4-azidoquinolines. A plausible mechanism, which implicates palladium hydride species in the reduction of the incipient 2,3-diaryl-4-azidoquinolines to afford the 4-amino-2,3-diarylquinolines is proposed.

One-pot synthesis of 2,3,4-triarylquinolines via suzuki-miyaura cross-coupling of 2-aryl-4-chloro-3-iodoquinolines with arylboronic acids.

Palladium-catalyzed Suzuki cross-coupling of 2-aryl-4-chloro-3-iodoquinolines with excess arylboronic acids (2.5 equiv.) in the presence of tricyclohexylphosphine afforded the 2,3,4-triarylquinolines in one-pot operation. The incipient 2,3-diaryl-4-chloroquinolines were also prepared and transformed to the primary 4-amino-2,3-diarylquinolines and 2,3-diarylquinolin-4(1H)-ones.

Molecular iodine-mediated cyclization of tethered heteroatom-containing alkenyl or alkynyl systems.

Molecular iodine has established itself as a readily available and easy-to-handle electrophilic and oxidizing reagent used in various organic transformations. In this review attention is focused on the use of molecular iodine in promoting cyclization (iodocyclization and cyclodehydroiodination) of tethered heteroatom-containing alkenyl or alkynyl systems.

Molecular iodine--an expedient reagent for oxidative aromatization reactions of alpha,beta-unsaturated cyclic compounds.

Prompted by the scant attention paid by published literature reviews to the applications of molecular iodine in oxidative aromatization reactions, we decided to review methods developed to-date involving iodine as an oxidant to promote aromatization of alpha,beta-unsaturated cyclic compounds.

Evaluation of the antiangiogenic effects of 2-aryl-3-bromoquinolin-4(1H)-ones and a NCH3-4-oxo derivative.

2-Aryl-3-bromoquinolin-4(1H)-ones and 2-aryl-3-bromo-1-methylquinolin-4(1H)-one were evaluated for their antiangiogenic effects. Results showed that the 2-aryl-3-bromoquinolin-4(1H)-ones (QNHFBr and QNHClBr), and the 3-bromo-2-(4-chlorophenyl)-1-methylquinolin-4(1H)-one (QNMeClBr) reduced endothelial cell numbers in an assay of cell proliferation, showing increased cytotoxicity at higher doses. The compounds also inhibited neovessel growth in an ex vivo assay of angiogenesis. Furthermore, low levels of proangiogenic factors, namely, basic fibroblast growth factor (bFGF) and vascular endothelial growth factor/placental growth factor (VEGF/PlGF) were obtained in cultures treated with these compounds. Thus, the tested compounds, QNHFBr, QNHClBr, and QNMeClBr exhibit antiangiogenic activity.