Targeted potent antimicrobial and antitumor oxygen-heterocyclic-based pyran analogues: synthesis and computational studies

The process of creating a series of 3-amino-1-aryl-8-methoxy-1H-benzo[f]chromene-2-carbonitriles (4a-q) involved reacting 6-methoxynaphthalen-2-ol (1), the appropriate aromatic aldehydes (2a-q), and malononitrile (3) in an absolute ethanol/piperidine solution under Ultrasonic irradiation. However, the attempt to create 3-amino-1-aryl-1H-benzo[f]chromene-2,8-dicarbonitrile (6a, d, e) was unsuccessful when 6-cyanonaphthalen-2-ol (5) was stirred at room temperature, reflux, Microwave irradiation, or Ultrasonic irradiation. In addition, the target molecules were screened against Staphylococcus aureus (MRSA), Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Escherichia coli and Klebsiella pneumonia, as well as a panel of three human cancer cells lines such as MCF-7, HCT-116, HepG-2 and two normal cell lines HFL-1 and WI-38. The obtained results confirmed that the pyran derivatives (4 m, i, k) which have a double chlorine at 3,4/2,3/2,5-positions, a single halogen atom 3-Cl/4-Br (4c, e) and a double bromine at 3,5-positions with a single methoxy group at 2-position (4n), of phenyl ring, and, to a lesser extent, other pyran derivatives with monoihalogenated (4a, b, d, f), dihalogenated (4 g, h, j, l) or trisubstituent phenyl ring (4o, p, q). Furthermore, compounds 4b-e, g, i, j, m, and n showed negligible activity against the two normal cell lines, HFL-1 and WI-38. Moreover, compound 4 g exhibited the strongest antimicrobial activity among the other pyran derivatives (4a-f, g-q) when compared to Ciprofloxacin. The MIC was assessed and screened for compound 4 g, revealing bactericidal effects. Lastly, SAR and molecular docking were studied.

Design, synthesis, and anticancer evaluation of N-sulfonylpiperidines as potential VEGFR-2 inhibitors, apoptotic inducers

A new panel of N-sulfonylpiperidine derivatives has been designed and synthesized as vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitors. Anti-proliferative activities of the synthesized members were tested against colorectal carcinoma (HCT-116), hepatocellular carcinoma (HepG-2), and breast cancer (MCF-7) cell lines. Compounds 3a, 4, 8, and 9 showed the highest activities against the tested cell lines. In particular, compound 8 showed excellent activities against HCT-116, HepG-2, and MCF-7 with IC50 values of 3.94, 3.76, and 4.43 μM, respectively. Such IC50 values are comparable to vinblastine (IC50 = 3.21, 7.35, 5.83 μM, respectively) and doxorubicin (IC50 = 6.74, 7.52, 8.19 μM, respectively). In vitro VEGFR-2 inhibitory activity of the most promising molecules (3a, 4, 8, and 9) indicated that compound 8 is the highest VEGFR-2 inhibitor with an IC50 of 0.0554 μM, compared to sorafenib (IC50 = 0.0416 μM). The most promising candidates (3a, 4, 8, and 9) were subjected to flow cytometry analyses to assess their effects on the cell cycle behavior and the apoptotic power against the three tested cell lines (HCT-116, HepG-2, and MCF-7). The tested compound arrested the tumor cells at both the G2/M and Pre-G1 phases. In addition, compound 9 was proved as the most effective apoptotic inducer among the tested compounds against the tested cells. Molecular docking studies against VEGFR-2 (PDB ID: 2OH4) revealed good binding modes of the synthesized compound similar to that of sorafenib. Computational investigation of ADMET parameters revealed the drug-likeness of the synthesized compounds.

Design, synthesis and bioactivity study on oxygen-heterocyclic-based pyran analogues as effective P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cell

P-glycoprotein (P-gp) imparts multi-drug resistance (MDR) on the cancers cell and malignant tumor clinical therapeutics. We report a class of newly designed and synthesized oxygen-heterocyclic-based pyran analogues (4a-l) bearing different aryl/hetaryl-substituted at the 1-postion were synthesized, aiming to impede the P-gp function. These compounds (4a-l) have been tested against cancerous PC-3, SKOV-3, HeLa, and MCF-7/ADR cell lines as well as non-cancerous HFL-1 and WI-38 cell lines to determine their anti-proliferative potency.The findings demonstrated the superior potency of 4a-c with 4-F, 2-Cl, and 3-Cl derivatives and 4h,g with 4-NO2, 4-MeO derivatives against PC-3, SKOV-3, HeLa, and MCF-7/ADR cell lines.Compounds 4a-c were tested for P-gp inhibition and demonstrated significant vigour against MCF-7/ADR cells with IC50 = 5.0-10.7 μM. The Rho123 accumulation assay showed that compounds 4a-c adequately inhibited P-gp function, as predicted. Furthermore, 4a or 4b administration resulted in MCF-7/ADR cell accumulation in the S phase, while compound 4c induced apoptosis by causing cell cycle arrest at G2/M. The molecular docking was applied to understand the likely modes of action and guide us in the rational design of more potent analogs. The investigate derivatives showed their good binding potential for p-gp active site with excellent docking scores and interactions. Finally, the majority of investigated derivatives 4a-c derivatives showed high oral bioavailability, but they did not cross the blood-brain barrier. These results suggest that they have favorable pharmacokinetic properties. Therefore, these compounds could serve as leads for designing more potent and stable drugs in the future.

Discovery of benzochromene derivatives first example with dual cytotoxic activity against the resistant cancer cell MCF-7/ADR and inhibitory effect of the P-glycoprotein expression levels

A series of 1H-benzo[f]chromene moieties (4a-z) were synthesised under Ultrasonic irradiation and confirmed with spectral analyses. Derivative 4i solely possessed an X-ray single crystal. The anti-proliferative efficacy of the desired molecules has been explored against three cancer cells: MCF-7, HCT-116, and HepG-2 with the cytotoxically active derivatives screened against MCF-7/ADR and normal cells HFL-1 and WI-38. Furthermore, compounds 4b-d, 4k, 4n, 4q, and 4w, which possessed good potency against MCF-7/ADR, were tested as permeability glycoprotein (P-glycoprotein [P-gp]) expression inhibitors. The attained data confirmed that 4b-d, 4q, and 4w exhibited strong expression inhibition against the P-gp alongside its cytotoxic effect on MCF-7/ADR. The western blot results and Rho123 accumulation assays showed that compounds 4b-d, 4q, and 4w effectively inhibited the P-gp expression and efflux function. Meanwhile, 4b-d, 4q, and 4w induced apoptosis and accumulation of the treated MCF-7/ADR cells in the G1 phase and 4k and 4n in the S phase of the cell cycle.

Introducing of novel class of pyrano[2,3-c]pyrazole-5-carbonitrile analogs with potent antimicrobial activity, DNA gyrase inhibition, and prominent pharmacokinetic and CNS toxicity profiles supported by molecular dynamic simulation

Microbiological DNA gyrase is recognized as an exceptional microbial target for the innovative development of low-resistant and more effective antimicrobial drugs. Hence, we introduced a one-pot facile synthesis of a novel pyranopyrazole scaffold bearing different functionalities; substituted aryl ring, nitrile, and hydroxyl groups. All new analogs were characterized with full spectroscopic data. The antimicrobial screening for all analogs was assessed against standard strains of Gm + ve and Gm-ve through in vitro considers. The screened compounds displayed very promising MIC/MBC values against some of the bacterial strains with broad or selective antibacterial effects. Of these, 4j biphenyl analog showed 0.5-2/2-8 µg/mL MIC/MBC for suppression and killing of Gm + ve and Gm-ve strains. Moreover, the antimicrobial screening was assessed for the most potent analogs against certain highly resistant microbial strains. Consequently, DNA gyrase supercoiling assay was done for all analogs using ciprofloxacin as reference positive control. Obviously, the results showed a different activity profile with potent analog 4j with IC50 value 6.29 µg/mL better than reference drug 10.2 µg/mL. Additionally, CNS toxicity testing was done using the HiB5 cell line for attenuation of GABA/NMDA expression to both 4j and ciprofloxacin compounds that revealed better neurotransmitter modulation by novel scaffold. Importantly, docking and dynamic simulations were performed for the most active 4j analog to investigate its interaction with DNA binding sites, which supported the in vitro observations and compound stability with binding pocket. Finally, a novel scaffold pyranopyrazole was introduced as a DNA gyrase inhibitor with prominent antibacterial efficacy and low CNS side effect toxicity better than quinolones.Communicated by Ramaswamy H. Sarma.

A novel class of phenylpyrazolone-sulphonamides rigid synthetic anticancer molecules selectively inhibit the isoform IX of carbonic anhydrases guided by molecular docking and orbital analyses

All the previously reported phenylpyrazoles as carbonic anhydrase inhibitors (CAIs) were found to have small sizes and high levels of flexibility, and hence showed low selectivity profiles toward a particular isoform of CA. Herein, we report the development of a more rigid ring system bearing a sulfonamide hydrophilic head and a lipophilic tail to develop novel molecules that are suggested to have a better selectivity toward a special CA isoform. Accordingly, three novel sets of pyrano[2,3-c]pyrazoles attached with sulfonamide head and aryl hydrophobic tail were synthesized to enhance the selectivity toward a specific isoform of human carbonic anhydrases (hCAs). The impact of both attachments on the potency and selectivity has been extensively discussed in terms of in vitro cytotoxicity evaluation under hypoxic conditions, structure-activity relationship and carbonic anhydrase enzyme assay. All of the new candidates displayed good cytotoxic activities against breast and colorectal carcinomas. Results of the carbonic anhydrase enzyme assay demonstrated the preferential of compounds 22, 24 and 27 to inhibit the isoform IX of hCAs selectively. Wound-healing assay has also been performed and revealed the potential of 27 to decrease the wound closure percentage in MCF-7 cells. Molecular docking and molecular orbital analysis have finally been conducted. Results indicate the potential binding interactions of 24 and 27 with several crucial amino acids of the hCA IX.Communicated by Ramaswamy H. Sarma.

The anticancer and EGFR-TK/CDK-9 dual inhibitory potentials of new synthetic pyranopyrazole and pyrazolone derivatives: X-ray crystallography, in vitro, and in silico mechanistic investigations

Treatment options for the management of breast cancer are still inadequate. This inadequacy is attributed to the lack of effective targeted medications, often resulting in the recurrence of metastatic disorders. Cumulative evidence suggests that epidermal growth factor receptor (EGFR-TK) and cyclin-dependent kinases-9 (CDK-9) overexpression correlates with worse overall survival in breast cancer patients. Pyranopyrazole and pyrazolone are privileged options for the development of anticancer agents. Inspired by this proven scientific fact, we report here the synthesis of two new series of suggested anticancer molecules incorporating both heterocycles together with their characterization by IR, 1H NMR, 13C NMR, 13C NMR-DEPT, and X-ray diffraction methods. An attempt to get the pyranopyrazole-gold complexes was conducted but unexpectedly yielded benzylidene-2,4-dihydro-3H-pyrazol-3-one instead. This unexpected result was confirmed by X-ray crystallographic analysis. All newly synthesized compounds were assessed for their anti-proliferative activity against two different human breast cancer cells, and the obtained results were compared with the reference drug Staurosporine. The target compounds revealed variable cytotoxicity with IC50 at a low micromolar range with superior selectivity indices. Target enzyme EGFR-TK and CDK-9 assays showed that compounds 22 and 23 effectively inhibited both biological targets with IC50 values of 0.143 and 0.121 µM, respectively. Molecular docking experiments and molecular dynamics simulation were also conducted to further rationalize the in vitro obtained results.Communicated by Ramaswamy H. Sarma.

Exploring the dual effect of novel 1,4-diarylpyranopyrazoles as antiviral and anti-inflammatory for the management of SARS-CoV-2 and associated inflammatory symptoms

COVID-19 and associated substantial inflammations continue to threaten humankind triggering death worldwide. So, the development of new effective antiviral and anti-inflammatory medications is a major scientific goal. Pyranopyrazoles have occupied a crucial position in medicinal chemistry because of their biological importance. Here, we report the design and synthesis of a series of sixteen pyranopyrazole derivatives substituted with two aryl groups at N-1 and C-4. The designed compounds are suggested to show dual activity to combat the emerging Coronaviruses and associated substantial inflammations. All compounds were evaluated for their in vitro antiviral activity and cytotoxicity against SARS-CoV infected Vero cells. As well, the in vitro assay of all derivatives against the SARS-CoV M^pro target was performed. Results revealed the potential of three pyranopyrazoles (22, 27, and 31) to potently inhibit the viral main protease with IC₅₀ values of 2.01, 1.83, and 4.60 μM respectively compared with 12.85 and 82.17 μM for GC-376 and lopinavir. Additionally, in vivo anti-inflammatory testing for the most active compound 27 proved its ability to reduce levels of two cytokines (TNF-α and IL-6). Molecular docking and dynamics simulation revealed consistent results with the in vitro enzymatic assay and indicated the stability of the putative complex of 27 with SARS-CoV-2 M^pro. The assessment of metabolic stability and physicochemical properties of 27 have also been conducted. This investigation identified a set of metabolically stable pyranopyrazoles as effective anti-SARS-CoV-2 M^pro and suppressors of host cell cytokine release. We believe that the new compounds deserve further chemical optimization and evaluation for COVID-19 treatment.

Synthesis of 9-Hydroxy-1H-Benzo[f]chromene Derivatives with Effective Cytotoxic Activity on MCF7/ADR, P-Glycoprotein Inhibitors, Cell Cycle Arrest and Apoptosis Effects

β-Enaminonitriles bearing 9-hydroxy-1H-benzo[f]chromene moiety was synthesized. The targeted compounds were evaluated for their anti-proliferative activity against three human tumor cell lines, PC-3, SKOV-3 and HeLa, and the active cytotoxic compounds were further evaluated against cancer cells, MCF-7/ADR, and two normal cell lines, HFL-1 and WI-38. Few compounds were assigned to be the most potent derivatives against PC-3, SKOV-3 and HeLa cell lines in comparison with Vinblastine and Doxorubicin. Several compounds possessed a relatively good potency against MCF-7/ADR cells as compared with Doxorubicin and were tested as a P-gp inhibitor. Moreover, the halogenated substituents, 2,4-F₂, 2,3-Cl₂, 2,5-Cl₂ and 3,4-Cl_2; have good potency against P-gp-mediated MDR in MCF-7/ADR as compared with Doxorubicin. Meanwhile, Rho123 accumulation assays revealed that few compounds effectively inhibited P-pg and efflux function. In addition, certain derivatives induced apoptosis and an accumulation of the treated MCF-7/ADR cells in the G1, S and G1/S phases.

In vitro and computational investigations of novel synthetic carboxamide-linked pyridopyrrolopyrimidines with potent activity as SARS-CoV-2-MPro inhibitors

An essential target for COVID-19 is the main protease of SARS-CoV-2 (M^pro). With the objective of targeting this receptor, a novel set of pyrido[1,2-a]pyrrolo[2,3-d]pyrimidines with terminal carboxamide fragments was designed, synthesized, and considered as an initial motif for the creation of effective pan-coronavirus inhibitors. Accordingly, nine derivatives (21–29) have been introduced for in vitro assay to evaluate their antiviral activity and cytotoxicity effect against COVID-19 virus using Vero cells. The obtained data revealed that the majority of these derivatives showed potent cellular anti-COVID-19 activity and prevent viral growth by more than 90% at two different concentrations with weak or even no detectable cytotoxic effect on Vero cells. Extensive molecular docking simulations highlighted proper non-covalent interaction of new compounds within the binding pocket of M^pro as a potential target for their antiviral activity. In vitro assay for all the synthesized derivatives against the viral M^pro target indicated that compounds 25 and 29 have promising inhibitory activity with IC₅₀ values at low micromolar concentrations. The molecular dynamic simulation results predicted the stability of compound 29 in the binding cavity of SARS-CoV-2 M^pro and hence supported the high inhibitory activity shown by the In vitro assay. These results suggested that compounds 25 and 29 merit further investigations as promising drug candidates for the management of SARS-CoV-2.

An essential target for COVID-19 is the main protease of SARS-CoV-2 (M^pro).

Synthesis of β-Enaminonitrile-Linked 8-Methoxy-1H-Benzo[f]Chromene Moieties and Analysis of Their Antitumor Mechanisms

A series of aryl-substituted 3-amino-1-aryl-8-methoxy-1H-benzo[f]chromene-2-carbonitriles (4a-4q) were designed and synthesized via reaction of 6-methoxy-2-naphthol with a mixture of appropriate aromatic aldehydes and malononitrile under microwave conditions. The structures of the novel compounds 4b, 4c, 4f, 4g, 4i, 4l, 4m, and 4o-4q were established according to IR, 1H-NMR, 13C-NMR/13C-NMR-DEPT, and MS. The benzochromene derivative 4c with a single chlorine at the meta position of the phenyl ring and, to a lesser extent, other benzochromenes with monohalogenated phenyl ring (4a, 4c-4f) exhibited the highest cytotoxicity against six human cancer cell lines MDA-MB-231, A549, HeLa, MIA PaCa-2, 5,637, and Hep G2. The mechanisms of the cytotoxic activities of benzochromenes with monohalogenated phenyl ring (4a, 4c-4f) were further analyzed using triple-negative breast cancer cell line MDA-MB-231. Cell cycle analysis showed accumulation of the treated cells in S phase for 4a, 4d-4f, and S-G2/M phases for 4c. In vivo, 4a and 4c-4f inhibited growth, proliferation, and triggered apoptosis in preestablished breast cancer xenografts grown on the chick chorioallantoic membranes while exhibiting low systemic toxicity. Compounds 4a and 4c-4f increased levels of mitochondrial superoxide and decreased mitochondrial membrane potential resulting in initiation of apoptosis as demonstrated by caspase 3/7 activation. In addition, 4c induced general oxidative stress in cancer cells. The SAR study confirmed that halogens of moderate size at meta or para positions of the pendant phenyl ring enhance the cytotoxic activity of 3-amino-1-aryl-8-methoxy-1H-benzo[f]chromene-2-carbonitriles, and these compounds could serve as leads for the development of novel anticancer therapies.

Synthesis and evaluation of antitumor activity of 9-methoxy-1H-benzo[f]chromene derivatives

Herein, a series of aryl-substituted derivatives of 3-amino-1-aryl-9-methoxy-1H-benzo[f]chromene-2-carbonitriles (4a-4q) were designed and synthesized via reaction of 7-methoxy-2-naphthol with a mixture of appropriate aromatic aldehydes and malononitrile under microwave conditions. Among the tested benzochromene, the known compound 4e and four novel compounds 4f, 4j, 4k, 4m exhibited the highest cytotoxicity towards a panel of six human cancer cell lines MDA-MB-231, A549, HeLa, MIA PaCa-2, RPMI 7951, and PC-3. Compound 4j with 2,4-dichloro substitution on the pendant phenyl ring exhibited the highest broad-spectrum cytotoxicity towards all tested cancer cell lines. Compounds 4e, 4f, 4j, 4k, 4m were further selected to study the mechanism of cellular toxicity using the triple-negative breast cancer cells MDA-MB-231. Compounds 4e, 4f, 4j, 4k, 4m induced accumulation of the treated MDA-MB-231 cells in the S phase and 4k additionally in the G₂/M phase of the cell cycle. Compounds 4e, 4f, 4j, 4k, 4m induced dissipation of mitochondrial transmembrane potential and activation of caspase 3/7 in MDA-MB-231 cells with 4j being one of the most active. In an in vivo model, compound 4j and less efficiently 4e and 4f inhibited growth and proliferation and triggered DNA fragmentation in MDA-MB-231 xenografts grown on chick chorioallantoic membranes. SAR study confirmed that the 2,4-dichloro substitution pattern on the pendant phenyl ring enhanced the cytotoxic activity of benzochromene.

Metal-free domino amination-Knoevenagel condensation approach to access new coumarins as potent nanomolar inhibitors of VEGFR-2 and EGFR

A metal-free, atom-economy and simple work-up domino amination-Knoevenagel condensation approach to construct new coumarin analogous (4a-f and 8a-e) was described. Further, new formyl (5a,d-f) and nitro (9a,d-f) coumarin derivatives were synthesized via C-N coupling reaction of various cyclic secondary amines and 4-chloro-3-(formyl-/nitro)coumarins (1a,c), respectively. The confirmed compounds were screened for their in vitro anti-proliferative activity against KB-3-1, A549 and PC3 human cancer cell lines using resazurin cellular-based assay. Among them, coumarin derivatives 4e and 8e displayed the best anti-cervical cancer potency (KB-3-1) with IC₅₀ values of 15.5 ± 3.54 and 21 ± 4.24 μM, respectively. Also, 4e showed the most promising cytotoxicity toward A549 with IC₅₀ value of 12.94 ± 1.51 μM. As well, 9d presented a more significant impact of potency against PC3 with IC₅₀ 7.31 ± 0.48 μM. Moreover, 8d manifested selectivity against PC3 (IC₅₀ = 20.16 ± 0.07 μM), while 8e was selective toward KB-3-1 cell line (IC₅₀ = 21 ± 4.24 μM). Matching with docking profile, the enzymatic assay divulged that 8e is a dual potent single-digit nanomolar inhibitor of VEGFR-2 and EGFR with IC₅₀ values of 24.67 nM and 31.6 nM that were almost equipotent to sorafenib (31.08 nM) and erlotinib (26.79 nM), respectively.

Targeted potent antimicrobial benzochromene-based analogues: Synthesis, computational studies, and inhibitory effect against 14α-Demethylase and DNA Gyrase

7H-Benzo[7,8]chromeno[2,3-d]pyrimidin-9(8H)-amine (6a,b) have been synthesized via hydrazinolysis of the imidates (5a,b). Polysubstituted chromenotriazolopyrimidine (7a-j), (12a,b) and Schiff base (8a,b) derivatives have also been prepared. The new heterocyclic derivatives were affirmed by spectral data. The target compounds have been screened for antibacterial and antifungal activity. Compounds 6a,b and 7a-c, g,h displayed the most favorable antimicrobial activities in resemblance to the reference antimicrobial agents by IZ range over 24 mm. In addition, MIC, MBC and MFC were also tested and screen for most active compound 6a by 6.25 µg/mL showing bactericidal effect. SAR study revealed that the antimicrobial vitality of the target compounds was safely influenced by the lipophilicity substituents and the calculated log P value. The potent compounds were subjected into in vitro enzyme screening (14α-Demethylase and DNA Gyrase) against both interesting targets and showed good inhibitory profile. Molecular modeling analyses were introduced and discussed focusing on the docking of active compounds into two essential targets, and their ADMET properties were studied.

Synthesis, anticancer evaluation and molecular docking studies of new heterocycles linked to sulfonamide moiety as novel human topoisomerase types I and II poisons

A series of heterocyclic compounds with a sulfonamide moiety were synthesized from reaction of enaminone 4 with active methylene compounds, glycine derivatives, 1,4-benzoquinone, hydroxylamine hydrochloride, hydrazonyl halides and dimethylacetylenedicarboxylate. The newly synthesized sulfonamide derivatives were characterized by FT-IR, ¹H NMR, ¹³C NMR, mass spectroscopy, elemental analysis and alternative synthetic routes. The reactions products were evaluated for their antiproliferative activity against a panel of three different human cancerous cell lines, MCF-7 (breast), HepG-2 (liver) and HCT-116 (colon) and the results were deployed to derive the structure-activity relationships (SAR). Various test compounds were potent antiproliferative to cancerous cells; reaching very low micromolar levels, as in case of 21 which showed IC₅₀ value of 6.2 μM against HepG-2 cell. In addition, treatment of cancerous cells with the synthesized compounds induced cell apoptosis and G2/M phase arrest evidenced by flow cytometric analysis. Furthermore, the activity of the synthesized compounds against TOP I and II were documented by DNA relaxation assays. Data revealed that compound 24 significantly interfered with TOP I- and II-mediated DNA relaxation, nicking and decatenation, with IC₅₀ values 27.8 and 33.6 μM, respectively. Moreover, the molecular docking studies supported the results from enzymatic assays, where compound 24 was intercalated between nucleotides flanking the DNA cleavage site via pi-pi stacking and hydrophobic interactions. In conclusion, aromatic heterocycles linked to sulfonamides are excellent molecular frameworks amenable for optimization as dual TOP I and II poisons to control various human malignancies.

A proficient microwave synthesis with structure elucidation and the exploitation of the biological behavior of the newly halogenated 3-amino-1H-benzo[f]chromene molecules, targeting dual inhibition of topoisomerase II and microtubules

In our endeavors to develop novel and powerful agents with antiproliferative activities, a series of β-enamionitriles, linked to the 8-bromo-1H-benzo[f]chromene moieties (4a-m), was designed and synthesized under microwave irradiation conditions. The structures of the target compounds were established on the basis of their spectral data: IR, ¹H NMR, ¹³C NMR, ¹³C NMR-DEPT/APT, ¹⁹F NMR and MS. Furthermore, the antiproliferative properties were evaluated against the human cancer cell lines MCF-7, HCT-116, and HepG-2 in comparison to the positive controls Vinblastine and Doxorubicin, employing the viability assay. The obtained results confirmed that most of the tested molecules revealed strong and selective cytotoxic activities against the three cancer cell lines. The most potent cytotoxic compounds 4b, 4d, 4e, 4i, and 4k were elected for further examination, such as the cell cycle analysis, the apoptosis assay, the Caspase production, and the DNA fragmentation. This study also revealed that the desired compounds stimulate cell cycle arrest at the G2/M phases, increase the production of Caspases 3, 8, and 9, and finally cause intrinsic and extrinsic apoptotic cell death. Moreover, these compounds suppress the action of the topoisomerase II enzyme and also disrupt the microtubule functions. The SAR study of the synthesized compounds verified that the substitution on the phenyl ring of the 1H-benzo[f]chromene nucleus, accompanied with the presence of the bromine atom at the 8-position, increases the ability of these molecules against different cell lines.

Rational Design and Synthesis of Diverse Pyrimidine Molecules Bearing Sulfonamide Moiety as Novel ERK Inhibitors

Protein kinases orchestrate diverse cellular functions; however, their dysregulation is linked to metabolic dysfunctions, associated with many diseases, including cancer. Mitogen-Activated Protein (MAP) kinase is a notoriously oncogenic signaling pathway in human malignancies, where the extracellular signal-regulated kinases (ERK1/2) are focal serine/threonine kinases in the MAP kinase module with numerous cytosolic and nuclear mitogenic effector proteins. Subsequently, hampering the ERK kinase activity by small molecule inhibitors is a robust strategy to control the malignancies with aberrant MAP kinase signaling cascades. Consequently, new heterocyclic compounds, containing a sulfonamide moiety, were rationally designed, aided by the molecular docking of the starting reactant 1-(4-((4-methylpiperidin-1-yl)sulfonyl)phenyl)ethan-1-one (3) at the ATP binding pocket of the ERK kinase domain, which was relying on the molecular extension tactic. The identities of the synthesized compounds (4–33) were proven by their spectral data and elemental analysis. The target compounds exhibited pronounced anti-proliferative activities against the MCF-7, HepG-2, and HCT-116 cancerous cell lines with potencies reaching a 2.96 μM for the most active compound (22). Moreover, compounds 5, 9, 10b, 22, and 28 displayed a significant G2/M phase arrest and induction of the apoptosis, which was confirmed by the cell cycle analysis and the flow cytometry. Thus, the molecular extension of a small fragment bounded at the ERK kinase domain is a valid tactic for the rational synthesis of the ERK inhibitors to control various human malignancies.

Microwave synthesis of novel halogenated β-enaminonitriles linked 9-bromo-1H-benzo[f]chromene moieties: Induces cell cycle arrest and apoptosis in human cancer cells via dual inhibition of topoisomerase I and II

A novel series of halogenated β-enaminonitriles (4a-m), linked 9-bromo-1H-benzo[f]-hromene moieties, were synthesized via microwave irradiation and were predestined for their cytotoxic activity versus three cancer cell lines, namely: MCF-7, HCT-116, and HepG-2. Several of the tested compounds showed high growth inhibitory activities versus the tumor cell lines. Particularly, compounds 4c, 4d, 4f, 4h, 4j, 4l, and 4m demonstrated superior antitumor activities against the aforementioned cell lines. Moreover, the apoptosis process in all the tested cells was induced by compounds 4c, 4d, 4h, 4l, and 4m, as observed by the Annexin V/PI double staining flow cytometric assay. The DNA flow, cytometric analysis revealed that these compounds prompted cell cycle arrest at the G2/M phases. Furthermore, the topoisomerase catalytic activity assays indicated that these compounds inhibited both the topoisomerase I and II enzymes.

Antiproliferative effect, cell cycle arrest and apoptosis generation of novel synthesized anticancer heterocyclic derivatives based 4H-benzo[h]chromene

Novel β-enaminonitrile/ester compounds (4, 6) and an imidate of 4 (9) were utilized as key scaffolds for the synthesis of newly 2-substituted 4H-benzo[h]chromene (7, 8, 10, 11, 13, 14) and 7H-benzo[h]chromeno[2,3-d]pyrimidine derivatives (15-19). The spectral data confirmed the successful isolation of the desired compounds. The targeted compounds were assessed for their in vitro anticancer activity against mammary gland breast cancer cell line (MCF-7), human colon cancer (HCT-116), and liver cancer (HepG-2), while doxorubicin, vinblastine, and colchicine were utilized as standard references drugs. Some of the examined compounds displayed high growth inhibitory activity against the three different cell lines. For example, the aminoimino derivative (18) exhibited excellent antitumor activity versus all cancer cell lines with IC₅₀ values = 0.45 µg/mL, 0.7 µg/mL, and 1.7 µg/mL. Among the tested molecules, compounds 9, 15, and 18 were selected for further study regarding their effects on cell cycle analysis, apoptosis assay, caspase 3/7 activity, and DNA fragmentation. We found that these three potent cytotoxic compounds induce cell cycle arrest at the S and G2/M phases, which causes apoptosis. Furthermore, these compounds significantly inhibit the invasion and migration of the different tested cancer cells. Finally, the SAR survey highlighted the antitumor activity of the new molecules that was remarkably influenced by the hydrophilicity of substituent as well the fused rings at certain positions.

Design and Synthesis of Novel Heterocyclic-Based 4H-benzo[h]chromene Moieties: Targeting Antitumor Caspase 3/7 Activities and Cell Cycle Analysis

Novel fused chromenes (4,7–11) and pyrimidines (12–16) were designed, synthesized, and evaluated for their mammary gland breast cancer (MCF-7), human colon cancer (HCT-116), and liver cancer (HepG-2) activities. The structural identity of the synthesized compounds was established according to their spectroscopic analysis, such as FT-IR, NMR, and mass spectroscopy. The preliminary results of the bioassay disclosed that some of the target compounds were proven to have a significant antiproliferative effect against the three cell lines, as compared to Doxorubicin, Vinblastine, and Colchicine, used as reference drugs. Particularly, compounds 7 and 14 exerted promising anticancer activity towards all cell lines and were chosen for further studies, such as cell cycle analysis, cell apoptosis, caspase 3/7 activity, DNA fragmentation, cell invasion, and migration. We found that these potent cytotoxic compounds induced cell cycle arrest at the S and G2/M phases, prompting apoptosis. Furthermore, these compounds significantly inhibit the invasion and migration of the different tested cancer cells. The structure-activity relationship (SAR) survey highlights that the antitumor activity of the desired compounds was affected by the hydrophobic or hydrophilic nature of the substituent at different positions.

Condensation of α-cyanocinnamonitriles with 6-bromo-2-naphthol: Synthesis of pyrano [2,3-d]pyrimidine and pyrano[3,2-e] [1,2,4]triazolo[2,3-c]pyrimidine derivatives

Naphthopyrans are synthesized by the reaction of cinnamonitriles with 6-bromo-2-naphthol; polysubstituted naph-thopyrimidines and naphthopyranotriazolopyrimidines are also prepared.

Introducing novel potent anticancer agents of 1H-benzo[f]chromene scaffolds, targeting c-Src kinase enzyme with MDA-MB-231 cell line anti-invasion effect

In our effort to develop novel and powerful agents with anti-proliferative activity, two new series of 1H-benzo[f]chromene derivatives, 4a–h and 6a–h, were synthesised using heterocyclocondensation methodologies under microwave irradiation condition. The structures of the target compounds were established on the basis of their spectral data, IR, ¹H NMR, ¹³ C NMR, ¹³ C NMR-DEPT/APT, and MS data. The new compounds have been examined for their anti-proliferative activity against three cancer cell lines, MCF-7, HCT-116, and HepG-2. Vinblastine and Doxorubicin have been used as positive controls in the viability assay. The obtained results confirmed that most of the tested molecules revealed strong and selective cytotoxic activity against the three cancer cell lines. Moreover, these molecules exhibited weak cytotoxicity on the HFL-1 line, which suggested that they might be ideal anticancer candidates. The SAR study of the new benzochromene compounds verified that the substituents on the phenyl ring of 1H-benzo[f]chromene nucleus, accompanied with the presence of bromine atom or methoxy group at the 8-position, increases the ability of these molecules against the different cell lines. Due to their high anti-proliferative activity, compounds 4c and 6e were selected to be examined their proficiency to inhibit the invasiveness of the highly sensitive and invasive breast cancer cell line, MDA-MB-231. The anti-invasion behaviour of these molecules against the highly sensitive, non-oestrogen, and progesterone MDA-MB-231 cell line gave rise to their decreasing metastatic effect compared to the reference drug. Furthermore, this report explores the apoptotic mechanistic pathway of the cytotoxicity of the target compounds and reveals that most of these compounds enhance the Caspase 3/7 activity that could be considered as potential anticancer agents.

Synthesis, biological activity and molecular modeling study of new Schiff bases incorporated with indole moiety

A new series of heterocyclic Schiff bases 2-9 containing indole moiety were synthesized by facile and efficient condensation of indole-3/2/5-carboxaldehyde (1a/1b/1c) with different aromatic and heterocyclic primary amines using conventional and/or microwave irradiation methods. The structures of the obtained compounds were assigned by sophisticated spectroscopic and spectrometric techniques (1D-NMR, 2D-NMR and MS). The synthesized compounds were screened for their cytotoxicity and antibacterial activities. In vitro cytotoxicity screening revealed that compound 5 exhibited moderate activity against KB-3-1 cell line (IC50=57.7 μM) while 5-indolylimino derivative 7 indicated close to the activity (IC50=19.6 μM) in comparison with the positive control (+)-Griseofulvin (IC50=19.2 μM), while the tested compounds 5, 6b, 7 and 9 revealed good or moderate antibacterial activity. In addition, molecular docking study of Schiff bases 2-9 was performed by Molecular Operating Environment (MOE 2014.09) program on the matrix metalloproteinase-8 (MMP-8) (Protein Data Bank (PDB) ID: 1MNC) in an attempt to explore their mode of action as anticancer drugs.

Synthesis and biological activities of new bis-indole derivatives via microwave irradiation

Three new series of bis-indole derivatives were synthesized based on p-phenylenediamine (2–4, 5 and 6) and 4,4′-ethylenedianiline moieties (7–9) using facile and efficient condensation of three positional isomeric indole-carboxaldehyde derivatives (1a–c) with bifunctional amines upon microwave irradiation. The symmetric dimeric indole derivatives 2–4 as well as non-symmetric analogues 5 and 6 were obtained by in situ condensation of the respective positional 3-, 2- and 5-isomeric indole-carboxaldehydes with p-phenylenediamine, while compounds 7–9 resulted from respective condensation based on 4,4′-ethylenedianiline. Structures of the obtained compounds were deduced by advanced spectroscopic methods (1H NMR, 13C NMR and MS). In agar diffusion assay, derivative 6 showed moderate antibacterial activity against various Gram positive and negative bacteria, while derivative 7 displayed moderate activity against several Gram positive bacteria. However, in Resazurin assay employing the human cervix carcinoma cell line (KB-3-1), derivatives 2–9 turned out to be inactive.

Crystal structure of 3-amino-1-(4-bromophenyl)-9-methoxy-1H-benzo[f]chromene-2-carbonitrile, C21H15BrN2O2

C21H15BrN2O2, triclinic, P1̅ (no. 2), a = 8.6873(3) Å, b = 9.9252(3) Å, c = 11.0013(3) Å, α = 77.977(2)°, β = 70.989(2)°, γ = 89.321(2)°, V = 875.55(5) Å3, Z = 2, Rgt(F) = 0.0369, wRref(F2) = 0.1043, T = 296(2) K.

Crystal structure of 3-amino-8-methoxy-1-(4-methoxy phenyl)-1H-benzo[f]chromene-2-carbonitrile, C22H18N2O3

C22H18N2O3, monoclinic, C2/c (no. 15), a = 35.4037(10) Å, b = 6.0294(2) Å, c = 20.1702(7) Å, β = 122.239(4)°, V = 3641.8(2) Å3, Z = 8, R gt(F) = 0.0482, wR ref(F 2) = 0.1406, T = 296(2) K.

Crystal structure of 3-amino-8-methoxy-1-phenyl-1H-benzo[f]chromene-2-carbonitrile, C21H16N2O2

C21H16N2O2, triclinic, P1̅ (no. 2), a = 8.5971(3) Å, b = 9.8586(3) Å, c = 10.6199(4) Å, α = 95.747(2)°, β = 104.384(2)°, γ = 101.768(2)°, V = 842.69(5) Å3, Z = 2, R gt(F) = 0.0482, wR ref(F 2) = 0.1377, T = 293(2).

New bioactive compounds from the marine-derived actinomycete Nocardiopsis lucentensis sp. ASMR2

In the search for new bioactive compounds from extremophilic actinomycetes, a new marine actinomycete strain, Nocardiopsis lucentensis sp. ASMR2 has been isolated and taxonomically identified from marine plants collected in the Red Sea at Hurghada coasts. A large-scale fermentation of the strain on modified rice solid medium was performed, followed by work-up and purification of the obtained extract using a series of chromatographic purifications, delivering the novel butenolide system 3′-hydroxy-N-(2-oxo-2,5-dihydrofuran-4-yl)propionamide (1a) along with the naturally new 4-methoxy-2H-isoquinolin-1-one (2). Furthermore, eight known bioactive compounds are also reported, namely, indole-3-carboxylic acid, indole-3-acetic acid, indole-3-acetic acid methyl ester, furan-2,5-dimethanol, tyrosol, glycerol linoleate, cyclo-(Tyr, Pro), and adenosine. The chemical structures of the new compounds (1a, 2) were confirmed by extensive one- and two-dimensional (1D and 2D) nuclear magnetic resonance (NMR) spectroscopy, electron ionization high resolution (EI-HR) mass spectrometry, and by comparison with literature data. The antimicrobial activity of the strain extract, as well as of compounds 1a and 2, were studied using a panel of pathogenic microorganisms. The in vitro cytotoxicity of the bacterial extract and compounds 1a and 2 were studied against the human cervix carcinoma cell line (KB-3-1) and its multidrug-resistant subclone (KB-V1).

Crystal structure of 3-amino-9-methoxy-1-phenyl-1H-benzo[f]chromene-2-carbonitrile, C21H16N2O2

C21H16N2O2, monoclinic, P21/n (no. 14), a = 13.4768(7) Å, b = 6.9225(3) Å, c = 18.2840(8) Å, β = 107.601(2)°, V = 1625.92(13) Å3, Z = 4, Rgt(F) = 0.0593, wRref(F2) = 0.1529, T = 100 K.

Structural Characterization and Antimicrobial Activities of 7H-Benzo[h]chromeno[2,3-d]pyrimidine and 14H-Benzo[h]chromeno[3,2-e][1,2,4]triazolo[1,5-c] pyrimidine Derivatives

Three new series of chromene molecules have been synthesized in order to explore their antimicrobial activity. The series encompass 2-substituted 14-(4-halophenyl)-12-methoxy-14H-benzo[h]chromeno[3,2-e][1,2,4]-triazolo[1,5-c]pyrimidines 7a-o, 9-benzylideneamino-7-(4-halo-phenyl)-5-methoxy-8-imino-7H-benzo-[h]chromeno[2,3-d]pyrimidines 8a-b and 3-ethoxycarbonyl-14-(4-halophenyl)-12-methoxy-14H-benzo-[h]chromeno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine-2-one derivatives 12a-b. The structure of these novel compounds were confirmed using IR, ¹H- and ¹³C-NMR as well as MS spectroscopy. The new compounds were evaluated in vitro for their antimicrobial activity and it was demonstrated that 7H-benzochromenopyrimidine and derivatives of 14H-benzochromenotriazolopyrimidine exhibited the most promising antibacterial activities compared to the reference antimicrobial agents. The structure activity relationship (SAR) studies of the target compounds agreed with the in vitro essays and confirmed higher potent antimicrobial activity against some of the tested microorganisms.

Synthesis of 9-Methoxy and 9-Acetoxy-3-amino-1-(4-methoxyphenyl)- 1H-benzo[f]chromene-2-carbonitriles via 2-(Imino-piperidin-1-yl-methyl)- 3-(4-methoxyphenyl)acrylonitrile as Intermediate

Several new 1H-benzo[f]chromene derivatives (3aÐd) were prepared by the reaction of 7-substituted-2-naphthols (1a,b) with substituted α-cyano-4-methoxycinnamonitriles (2a,b) together with 2-(imino-piperidin-1-yl-methyl)-3-(4-methoxyphenyl)acrylonitrile (4) as intermediate. Also, the reaction of 1a,b with 4 without catalyst afforded 9-methoxy and 9-acetoxy- 3-amino-1-(p-methoxyphenyl)-1H-benzo[f]chromene-2-carbonitrile (3b,e). The reaction of 3a,b with different electrophilic and nucleophilic reagents afforded the 12H-7-oxa-8,10-diazabenzo[ a]anthracene derivatives 5, 9, 10 and 1H-benzo[f]chromene derivatives 6Ð8, 11.

2-Amino-4-(4-bromo-phen-yl)-6-meth-oxy-4H-benzo[h]chromene-3-carbonitrile

In the title compound, C21H15BrN2O2, the 14 non-H atoms of the 4H-benzo[h]chromene fused-ring system are approximately coplanar (r.m.s. deviation = 0.129 Å). Within this system, the 4H-pyran ring adopts a flattened half-chair conformation with the methine C atom lying 0.281 (4) Å above the plane of the remaining atoms (r.m.s. deviation = 0.0446 Å). The bromo-benzene ring is almost perpendicular to the fused-ring system [dihedral angle = 85.34 (13)°]. In the crystal, supra-molecular layers parallel to (101) are sustained by amine-cyano N-H⋯N and amine-meth-oxy N-H⋯O hydrogen bonds. The layers stack with inter-actions of the type (bromo-benzene)C-H⋯π(outer-C6 ring of the fused-ring system) connecting them.

3-Amino-1-(4-fluoro-phen-yl)-7-meth-oxy-1H-benzo[f]chromene-2-carbonitrile

In the title compound, C₂₁H₁₅FN₂O₂, the furan ring has a flattened half-chair conformation [the methine C atom lies 0.136 (2) Å above the C₅ plane which has an r.m.s. deviation of 0.0229 Å]. Overall, the 1H-benzo[f]chromene fused-ring system approximates a plane (r.m.s. deviation of the 14 non-H atoms = 0.049 Å). The fluoro­benzene ring is almost perpendicular to this plane [dihedral angle = 89.58 (8)°]. Zigzag supra­molecular tapes along the b axis are the most notable feature of the crystal packing. This arises through an alternating sequence of 12-membered {⋯HNC₃N}₂ and eight-membered {⋯HNCO}₂ synthons. These are connected into a three-dimensional architecture by π–π [inter­centroid distance for centrosymmetrically related fluoro­benzene rings = 3.5181 (10) Å] and C—H⋯π inter­actions.

3-Amino-1-(4-fluoro-phen-yl)-8-meth-oxy-1H-benzo[f]chromene-2-carbonitrile

The title compound, C₂₁H₁₅FN₂O₂, features an approximately planar 1H-benzo[f]chromene fused-ring system (r.m.s. deviation for the 14 non-H atoms = 0.052 Å), with the fluoro­benzene ring being almost perpendicular to this [dihedral angle = 85.30 (7) °]. The furan ring has a flattened half-chair conformation, with the methine C atom deviating by 0.132 (2) Å from the plane of the remaining atoms (r.m.s. deviation = 0.0107 Å). In the crystal, inversion dimers are formed via pairs of amine–cyano N—H⋯N hydrogen bonds. The dimers are connected into a three-dimensional architecture by C—H⋯N(cyano), C—H⋯π and π–π [inter­centroid distance = 3.6671 (10) Å] inter­actions.

N'-[3-Cyano-4-(4-fluoro-phen-yl)-6-meth-oxy-4H-benzo[h]chromen-2-yl]-N,N-dimethyl-methanimidamide

In the title compound, C24H20FN3O2, despite the 4H-pyran ring having a flattened half-chair conformation [the methine C atom lies 0.257 (3) Å above the plane of the remaining atoms with an r.m.s. deviation of 0.0295 Å], the 14 non-H atoms of the 4H-benzo[h]chromene residue are approximately coplanar (r.m.s. deviation = 0.081 Å). The benzene ring is nearly perpendicular to this plane [dihedral angle = 76.18 (10)°], but the planar (r.m.s. deviation = 0.033 Å) dimethyl-methanimidamide substituent is coplanar [dihedral angle = 1.96 (12)°]. In the crystal, centrosymmetric dimeric aggregates arise from C-H⋯N inter-actions, and these are connected into supra-molecular layers in the ab plane by C-H⋯π and π-π [inter-centroid (central C6 ring)⋯(outer C6 ring)(i) distance = 3.8564 (14) Å] inter-actions.