Synthesis of Indole-Fused Pyrazino[1,2-a]quinazolinones by Copper(I)-Catalyzed Selective Hydroamination-Cyclization of Alkynyl-tethered Quinazolinones.

We described a copper(I)-catalyzed atom economic and selective hydroamination-cyclization of alkynyl-tethered quinazolinones to prepare a variety of indole-fused pyrazino[1,2-a]quinazolinones in good to excellent yields ranging from 39 %-99 % under mild reaction conditions. Control experiments revealed that coordination-directed method of quinazolinone moiety with copper(I) was important for the selective hydroamination-cyclization of alkynes at the N1-atom instead of N3-atom of quinazolinone. The reaction could be easily performed at gram scales and some prepared indole-fused pyrazino[1,2-a]quinazolinones with donating groups on the indole moiety showed a distinct fluorescence emission wavelength with blue shift under the acid conditions.

Skeletal Editing through Molecular Recombination of 2H-Indazoles to Azo-Linked-Quinazolinones.

A new protocol by the combinatory use of two equivalent of indazoles starting material with one being the carbon source via its C3-reactivity and the other, the coupling partner has been developed for the selectfluor-mediated single atom skeletal editing of 2H-indazoles. The azo-linked-2,3-disubstituted quinazolin-4-one derivatives were obtained through a carbon atom insertion between the two nitrogens of the indazole ring and simultaneous oxidation at C3 position of both indazole moieties. Mechanistic investigations reveal that the amidic carbonyl oxygen of the product is derived from water and the reaction proceeds through in-situ generated N-centred indazolone radical intermediate.

Design, synthesis and molecular docking study of novel triazole-quinazolinone hybrids as antimalarial and antitubercular agents.

In a quest to discover new antimalarial and antitubercular drugs, we have designed and synthesized a series of novel triazole-quinazolinone hybrids. The in vitro screening of the triazole-quinazolinone hybrid entities against the plasmodium species P. falciparum offered potent antimalarial molecules 6c, 6d, 6f, 6g, 6j & 6k owing comparable activity to the reference drugs. Furthermore, the target compounds were evaluated in vitro against Mycobacterium tuberculosis (MTB) H37Rv strain. Among the screened compounds, 6c, 6d and 6l were found to be the most active molecules with a MIC values of 19.57-40.68 µM. The cytotoxicity of the most active compounds was studied against RAW 264.7 cell line by MTT assay and no toxicity was observed. The computational study including drug likeness and ADMET profiling, DFT, and molecular docking study was done to explore the features of target molecules. The compounds 6a, 6g, and 6k exhibited highest binding affinity of -10.3 kcal/mol with docked molecular targets from M. tuberculosis. Molecular docking study indicates that all the molecules are binding to the falcipain 2 protease (PDB: 6SSZ) of the P. falciparum. Our findings indicated that these new triazole-quinazolinone hybrids may be considered hit molecules for further optimization studies.

Furan-Dihydroquinazolinone Based Fluorescent Nanoprobe for Selective Recognition of 4-Nitrophenol: A Spectofluorimetric Approach.

Fluorescent organic nanoparticles (FONPs) have attracted much attention as a practicable and effective platform for detection applications. The present article describes the preparation of FONPs derived from the quinazolinone-based 2-(furan-2-yl)-2,3-dihydroquinazolin-4(1H)-one derivative FHDQ. Self-assembly of FHDQ in an aqueous medium resulted in the formation of FONPs through H-type aggregation and showed excellent fluorescence properties. The presence of other coexisting species solutions did not affect the selective fluorescence quenching observed with the addition of 4-nitrophenol (4-NP). The photophysical properties, i.e., UV-Vis absorbance, fluorescence emission, and lifetime measurements together with zeta particle sizer, support excited-state complex formation followed by a dynamic fluorescence quenching phenomenon in the emission of FDHQNPs. In the concentration range of 0 to 36 µg.[Formula: see text], the detection limit of this turn-off sensor FDHQNPs against 4-NP was determined to be 0.01611 µM. Finally, the practicability of the FDHQNPs for the analysis of 4-NP in environmental samples was demonstrated.

Novel quinazolinone Derivatives: Design, synthesis and in vivo evaluation as potential agents targeting Alzheimer disease.

Since Alzheimer disease is one of the most prevalent types of dementia with a high mortality and disability rate, so development of multi-target drugs becomes the major strategy for battling AD. This study shows the development of a series of quinazolinone based derivatives as novel, multifunctional anti-AD drugs that exhibit both cholinesterase inhibitoryand anti-inflammatory properties. The preliminary results of the in vitro AChE inhibition activity showed that compounds 4b, 5a, 6f, 6h and 7b were better represented for further evaluation. Furthermore, in-vivo AChE inhibition activity and behavior Morris water maze test against donepezil as reference drug were evaluated. Additionally, hippocampal inflammatory markers; TNF-α, NFĸB, IL-1ß and IL-6 and antioxidant markers; SOD and MDA were assessed to evaluate the efficacy of quinazolinone derivatives against AD hallmarks. The results showed that 6f, 6h and 7b have promising anti-acetylcholinesterase, anti-inflammatory and antioxidant activities thus, have a significant effect in treatment of AD. Moreover, Histopathological examination revealed that 6f, 6h and 7b derivatives have neuroprotective effect against neuronal damage caused by induced scopolamine model in mice. Finally, the binding ability of the synthesized derivatives to the target, AChE was investigated through molecular docking which reflected significant interactions to the target based on their docking binding scores. Hence, the newly designed quinazolinone derivatives possess promising anti-acetylcholinesterase activity and challenging for the management of AD in the future.

Rational design and synthesis of novel quinazolinone N-acetohydrazides as type II multi-kinase inhibitors and potential anticancer agents.

In the current investigation, a new class of quinazolinone N-acetohydrazides 9a-v was designed as type II multi-kinase inhibitors. The target quinazolinones were tailored so that the quinazolinone moiety would occupy the front pocket of the binding sites of VEGFR-2, FGFR-1 and BRAF kinases, meanwhile, the phenyl group at position 2 would act as a spacer which was functionalized at position 4 with an N-acetohydrazide linker that could achieve the key interactions with the essential gate area amino acids. The hydrazide moiety was linked to diverse aryl derivatives to occupy the hydrophobic back pocket of the DFG-out conformation of target kinases. The synthesized quinazolinone derivatives 9a-v demonstrated moderate to potent VEGFR-2 inhibitory activity with IC50 spanning from 0.29 to 5.17 µM. Further evaluation of the most potent derivatives on FGFR-1, BRAFWT and BRAFV600E showed that the quinazolinone N-acetohydrazides 9d, 9e, 9f, 9l and 9m have a potent multi-kinase inhibitory activity. Concurrently, 9b, 9d, 9e, 9k, 9l, 9o, 9q demonstrated potent growth inhibitory activity on NCI cancer cell lines with GI50 reaching 0.72 µM. In addition, compound 9e arrested the cell cycle progression in MDA-MB-231 cell line at the G2/M phase and showed the ability to induce apoptosis.

Syntheses and Cytotoxicities of Quinazolinone-Based Conjugates.

Two novel series of quinazolinone-based hybrids, including quinazolinone-1,3,4-oxadiazoles (10a-l) and quinazolinone-1,3,4-oxadiazole-benzimidazoles (8a-e), were designed and synthesized and their cytotoxic activities against three human cancer cell lines, lung cancer (A549), cervical cancer (HeLa), and breast cancer (MCF-7), were evaluated. The cytotoxic assays revealed that 10i with a lipophilic 4-fluoro-phenyl moiety at the C-2 position of the quinazolinone ring displayed good cytotoxicities against the A549 and MCF-7 cell lines, while 8b-d with the thioether-linked benzimidazole moiety incorporated on the right side of the oxadiazole ring induced comparable stronger activities toward the MCF-7 cell line, relative to the simple two-heterocycle-containing hybrid 10i. These novel quinazolinone-based hybrids could be considered as lead compounds that merit further optimization and development as anti-cancer agents.

Flavonol Derivatives Containing a Quinazolinone Moiety: Design, Synthesis, and Antiviral Activity.

A series of flavonol derivatives containing quinazolinone were designed and synthesized, and their antiviral activities against tobacco mosaic virus (TMV) were evaluated. The results of the half maximal effective concentration (EC50 ) test against TMV showed that the EC50 value of curative activity of K5 was 139.6 µg/mL, which was better than that of the commercial drug ningnanmycin (NNM) 296.0 µg/mL, and the EC50 value of protective activity of K5 was 120.6 µg/mL, which was superior to that of NNM 207.0 µg/mL. The interaction of K5 with TMV coat protein (TMV-CP) was investigated using microscale thermophoresis (MST) and molecular docking and the results showed that K5 can combine with TMV-CP more strongly to TMV-CP than that NNM can. Furthermore, the assay measuring malondialdehyde (MDA) content indicated that K5 had the ability to improve the disease resistance of tobacco. Hence, this study offers strong evidence that flavonol derivatives have potential as novel antiviral agents.

A literature review on pharmacological aspects, docking studies, and synthetic approaches of quinazoline and quinazolinone derivatives.

Quinazoline and quinazolinone derivatives piqued medicinal chemistry interest in developing novel drug candidates owing to their pharmacological potential. They are important chemicals for the synthesis of a variety of physiologically significant and pharmacologically useful molecules. Quinazoline and quinazolinone derivatives have anticancer, anti-inflammatory, antidiabetic, anticonvulsant, antiviral, and antimicrobial potential. The increased understanding of quinazoline and quinazolinone derivatives in biological activities provides opportunities for new medicinal products. The present review focuses on novel advances in the synthesis of these important scaffolds and other medicinal aspects involving drug design, structure-activity relationship, and action mechanisms of quinazoline and quinazolinone derivatives to help in the development of new quinazoline and quinazolinone derivatives.

Synthesis and evaluation of febrifugine derivatives as anticoccidial agents.

A series of new febrifugine derivatives with a 4(3H)-quinazolinone scaffold were synthesized and evaluated for their anticoccidial activity both in vitro and in vivo. The targets' in vitro activity against Eimeria tenella was studied using quantitative real-time reverse transcription polymerase chain reaction and Madin-Darby bovine kidney cells. Most of these compounds demonstrated anticoccidial efficacy, with inhibition ratios ranging from 3.3% to 85.7%. Specifically, compounds 33 and 34 showed significant inhibitory effects on the proliferation of E. tenella and exhibited lower cytotoxicity compared to febrifugine. The IC50 values of compounds 33 and 34 were 3.48 and 1.79 µM, respectively, while the CC50 values were >100 µM for both compounds. Furthermore, in a study involving 14-day-old chickens infected with 5 × 104 sporulated oocysts, treatment with five selected compounds (22, 24, 28, 33, and 34), which exhibited in vitro inhibition rate of over 50% at 100 µM, at a dose of 40 mg/kg in daily feed for 8 consecutive days showed that compound 34 possessed moderate in vivo activity against coccidiosis, with an anticoccidial index of 164. Structure-activity relationship studies suggested that spirocyclic piperidine may be a preferable substructure to maintain high effectiveness in inhibiting Eimeria spp., when the side chain 1-(3-hydroxypiperidin-2-yl)propan-2-one was replaced.

A New Quinazolinone Alkaloid along with Known Compounds with Seed-Germination-Promoting Activity from Rhodiola tibetica Endophytic Fungus Penicillium sp. HJT-A-6.

A new quinazolinone alkaloid named peniquinazolinone A (1), as well as eleven known compounds, 2-(2-hydroxy-3-phenylpropionamido)-N-methylbenzamide (2), viridicatin (3), viridicatol (4), (±)-cyclopeptin (5a/5b), dehydrocyclopeptin (6), cyclopenin (7), cyclopenol (8), methyl-indole-3-carboxylate (9), 2,5-dihydroxyphenyl acetate (10), methyl m-hydroxyphenylacetate (11), and conidiogenone B (12), were isolated from the endophytic Penicillium sp. HJT-A-6. The chemical structures of all the compounds were elucidated by comprehensive spectroscopic analysis, including 1D and 2D NMR and HRESIMS. The absolute configuration at C-13 of peniquinazolinone A (1) was established by applying the modified Mosher's method. Compounds 2, 3, and 7 exhibited an optimal promoting effect on the seed germination of Rhodiola tibetica at a concentration of 0.01 mg/mL, while the optimal concentration for compounds 4 and 9 to promote Rhodiola tibetica seed germination was 0.001 mg/mL. Compound 12 showed optimal seed-germination-promoting activity at a concentration of 0.1 mg/mL. Compared with the positive drug 6-benzyladenine (6-BA), compounds 2, 3, 4, 7, 9, and 12 could extend the seed germination period of Rhodiola tibetica up to the 11th day.

Design, synthesis, molecular docking, and in vitro studies of 2-mercaptoquinazolin-4(3H)-ones as potential anti-breast cancer agents.

Triple-negative breast cancer (TNBC) comprises 10 % to 20 % of breast cancer, however, it is more dangerous than other types of breast cancer, because it lacks druggable targets, such as the estrogen receptors (ER) and the progesterone receptor (PR), and has under expressed receptor tyrosine kinase, ErbB2. Present targeted therapies are not very effective and other choices include invasive procedures like surgery or less invasive ones like radiotherapy and chemotherapy. This study investigated the potential anticancer activity of some novel quinazolinone derivatives that were designed on the structural framework of two approved anticancer drugs, Ispinesib (KSP inhibitor) and Idelalisib (PI3Kδ inhibitor), to find out solutions for TNBC. All the designed derivatives (3a-l) were subjected to extra precision molecular docking and were synthesized and spectrally characterized. In vitro enzyme inhibition assay of compounds (3a, 3b, 3e, 3 g and 3 h) revealed their nanomolar inhibitory potential against the anticancer targets, KSP and PI3Kδ. Using MTT assay, the cytotoxic potential of compounds 3a, 3b and 3e were found highest against MDA-MB-231 cells with an IC50 of 14.51 µM, 16.27 µM, and 9.97 µM, respectively. Remarkably, these compounds were recorded safe against the oral epithelial normal cells with an IC50 values of 293.60 µM, 261.43 µM, and 222 µM, respectively. The anticancer potential of these compounds against MDA-MB-231 cells was revealed to be associated with their apoptotic activity. This was established by examination with the inverted microscope that revealed the appearance of various apoptotic features like cell shrinkage, apoptotic bodies, and membrane blebbing. Using flow cytometry, the Annexin V/PI-stained cancer cells showed an increase in early and late apoptotic cells. In addition, DNA fragmentation was revealed to occur after treatment with the tested compounds by gel electrophoresis. The relative gene expression of pro-apoptotic and anti-apoptotic genes revealed an overexpression of the P53 and BAX genes and a downregulation of the BCL-2 gene by real-time PCR. So, this work proved that compounds 3a, 3b, and 3e could be developed as anticancer candidates, via their P53-dependent apoptotic activity.

CO-Preserving Photoinduced Transfer of Cymantrenyl Moiety: a Tandem Experimental and Computational Investigation.

Cyclopentadienyl manganese tricarbonyl (cymantrene) is known to undergo photochemical reactions by releasing one of its CO ligands. Here we present the first example of a photorearrangement of a cymantrenylmethyl fragment, where it retains all its three CO ligands. A tandem experimental and DFT (density functional theory)-based computational investigation allows us to explain this unexpected behavior: the rearrangement, indeed, begins with the release of one CO ligand, but cage effect of the solvent captures this CO molecule, allowing it to rapidly reattach once the rearrangement takes place.

Novel quinazolinone disulfide analogues as pqs quorum sensing inhibitors against Pseudomonas aeruginosa.

It is well established that the quorum sensing (QS) in Pseudomonas aeruginosa is primarily responsible for the synthesis and the release of several virulence factors including pyocyanin and are involved in biofilm formation. In the Pseudomonas quinolone signal (PQS) system, autoinducers such as PQS and HHQ bind and activate the transcription regulator protein receptor PqsR (MvfR). Targeting PqsR with competitive inhibitors could be a promising strategy to inhibit QS in P. aeruginosa to overcome antimicrobial resistance. In this study, we have designed and synthesized a series of novel quinazolinone disulfide-containing competitive inhibitor of PqsR. The most potent analogue 8q efficiently inhibited the pqs system with an IC50 value of 4.5 µM. It also showed complete suppression of pyocyanin production and a significant reduction in biofilm formation by P. aeruginosa (PAO1) with low cytotoxicity. Additionally, 8q produced synergy in combination with known antibiotics such as ciprofloxacin and tobramycin. Finally, molecular docking analysis suggested that compound 8q could bind with the ligand-binding domain of PqsR in a similar fashion to the native ligand.

Design, synthesis, X-ray crystal structure, and antimicrobial evaluation of novel quinazolinone derivatives containing the 1,2,4-triazole Schiff base moiety and an isopropanol linker.

A series of novel quinazolinone derivatives (E1-E31) containing the 1,2,4-triazole Schiff base moiety and an isopropanol linker were designed, synthesized and assessed as antimicrobial agents in agriculture. All the target compounds were fully characterized by 1 H NMR, 13 C NMR, and high-resolution mass spectrometry (HRMS). Among them, the structure of compound E12 was further confirmed via single crystal X-ray diffraction method. The experimental results indicated that many compounds displayed good in vitro antibacterial efficacies against the tested phytopathogenic bacteria including Xanthomonas oryzae pv. oryzae (Xoo), Xanthomonas axonopodis pv. citri (Xac), and Ralstonia solanacearum (Rs). For example, compounds E3, E4, E10, E13, and E22 had EC50 (half-maximal effective concentration) values of 55.4, 39.5, 49.5, 53.5, and 57.4 µg/mL against Xoo, respectively, superior to the commercialized bactericide Bismerthiazol (94.5 µg/mL). In addition, the antibacterial efficacies of compounds E10 and E13 against Xac were about two times more effective than control Bismerthiazol, in terms of their EC50 values. Last, the antifungal assays showed that compounds E22 and E30 had the inhibition rates of 52.7% and 54.6% at 50 µg/mL against Gibberella zeae, respectively, higher than the commercialized fungicide Hymexazol (48.4%).

Nano-CuFe2O3-catalyzed green synthesis of novel quinazolinone-tetrazole hybrids as anti-cancer agents.

A novel green protocol has been developed for the synthesis of quinazolinone-tetrazole conjugates (7a-g, 8a-g and 9a-g) using recyclable nano-CuFe2O3 catalyst in water. Initially, 2-mercapto-3-substituted phenethylquinazolin-4(3H)-one (5a-c) was prepared by using nano-CuFe2O3 catalyst in water. Then, compounds (5a-c) were reacted with 1-bromo-3-chloropropane under nano-CuFe2O3 catalyst in water solvent to give S-alkylated quinazolinone core intermediate (6a-c), which was subsequently reacted with 1-substituted-1H-tetrazole-5-thiol (2a-g) by employing the similar reaction conditions to afford the final target compounds. The regioselective formation of C-S bond was unambiguously confirmed by single-crystal X-ray diffraction. The anti-cancer activity of the derivatives on various cancer cell lines such as SIHA, MD-AMB-231 and HepG2 was evaluated. Remarkably, compounds, 7f, 8f, 9a, 9d and 9f, showed potent activity in MD-AMB-231 cancer cell line (IC50: 9.13-10.3 µM), while the same derivatives showed significant potent activity in SiHa and HepG2 cancer cell lines (IC50: 17.46-27.0 µM). Most significantly, compound 7o (IC50: 8.15 µM) showed potent activity, compared to the drug etoposide (IC50: 18.11 µM) against MD-AMB-231 cell line. Flow cytometry analysis revealed that compounds 7f, 8f, 9a, 9d and 9f arrested the cell growth in the G1 phase in MD-AMB-231 cell line.

Actinoquinazolinone, a New Quinazolinone Derivative from a Marine Bacterium Streptomyces sp. CNQ-617, Suppresses the Motility of Gastric Cancer Cells.

A HPLC-UV guided fractionation of the culture broth of Streptomyces sp. CNQ-617 has led to the isolation of a new quinazolinone derivative, actinoquinazolinone (1), as well as two known compounds, 7-hydroxy-6-methoxy-3,4-dihydroquinazolin-4-one (2) and 7-methoxy-8-hydroxy cycloanthranilylproline (3). The interpretation of 1D, 2D NMR, and MS spectroscopic data revealed the planar structure of 1. Furthermore, compound 1 suppressed invasion ability by inhibiting epithelial-mesenchymal transition markers (EMT) in AGS cells at a concentration of 5 µM. In addition, compound 1 decreased the expression of seventeen genes related to human cell motility and slightly suppressed the signal transducer and activator of the transcription 3 (STAT3) signal pathway in AGS cells. Together, these results demonstrate that 1 is a potent inhibitor of gastric cancer cells.

Synthesis and Evaluation of Marine-Inspired Compounds Result in Hybrids with Antitrypanosomal and Antileishmanial Activities.

Natural products are a very rich source for obtaining new compounds with therapeutic potential. In the search for new antiparasitic and antimicrobial agents, molecular hybrids were designed based on the structures of antimicrobial marine quinazolinones and eugenol, a natural phenolic compound. Following reports of the therapeutic potential of quinazolinones and eugenol derivatives, it was expected that the union of these pharmacophores could generate biologically relevant substances. The designed compounds were obtained by classical synthetic procedures and were characterized by routine spectrometric techniques. Nine intermediates and final products were then evaluated in vitro against Trypanosoma brucei and Leishmania infantum. Antifungal and antibacterial activity were also evaluated. Six compounds (9b, 9c, 9d, 10b, 10c, and 14) showed mild activity against T. brucei with IC50 in the range of 11.17-31.68 µM. Additionally, intermediate 9c showed anti-Leishmania activity (IC50 7.54 µM) and was six times less cytotoxic against THP-1 cells. In conclusion, novel derivatives with a simple quinazolinone scaffold showing selectivity against parasites without antibacterial and antifungal activities were disclosed, paving the way for new antitrypanosomal agents.

Design, Synthesis and Antitumor Activity of FAK/PLK1 Dual Inhibitors with Quinazolinone as the Skeleton.

Febrifugine is a kind of quinazolinone compound with high biological activity from a Chinese herb called Chang Shan (Dichroa febrifuga). Febrifugine and its derivatives possess extensive biological activities, some of which exhibited anti-tumor activities as FAK inhibitors. However, they are not very effective at inhibiting tumor metastasis, perhaps because tumors gain energy through compensatory activation of other signaling pathways that promote cell migration and invasion. Therefore, seventeen novel febrifugine derivatives with quinazolinone skeleton were designed, synthesized and acted as potential FAK/PLK1 dual inhibitors. These compounds were determined by 1 H-NMR, 13 C-NMR and MS. Most of the compounds exhibited good inhibitory activity against cancer cell lines by computer-assisted screening, antitumor activity test and FAK/PLK1 inhibitory activity test, wherein compound 3b was screened as a high-efficiency lead compound.

Design, Synthesis of Novel 1,2,3-Triazole Pendent Quinazolinones and Their Cytotoxicity against MCF-7 Cell Line.

A library of 6-(((1-(substitutedphenyl)-1H-1,2,3-triazol-4-yl)methyl) amino)-3-methylquinazolin-4(3H)-one analogues synthesized from Isatin precursor through a series of nitration, reduction, hydrolysis, cyclization and click reaction. The structures of compounds were characterized by spectral data including IR, 1 H-NMR, 13 C NMR and Mass. The novel quinazolinone - 1,2,3-triazoles were screened for their cytotoxicity against the human breast adenocarcinoma cell lines MCF-7 by MTT assay. 4-Isopropyl and 2-bromo substituted analogues executed high activity against MCF-7 cell line with IC50 value of 10.16±0.07 µM and 11.23±0.20 µM compared to the Doxorubicin whose IC50 value is 10.81±0.03 µM. The activity of remaining compounds is good to moderate. Further, the molecular docking studies against the crystal structure of Epidermal Growth Factor Receptor delivered the best binding energies and the interactions such as H-bond and hydrophobic are inevitable. The predicted pharmacokinetic properties results showed that these compounds have more drug likeness properties.