Synthesis of Triazole-Substituted Quinazoline Hybrids for Anticancer Activity and a Lead Compound as the EGFR Blocker and ROS Inducer Agent.

A series of triazole-substituted quinazoline hybrid compounds were designed and synthesized for anticancer activity targeting epidermal growth factor receptor (EGFR) tyrosine kinase. Most of the compounds showed moderate to good antiproliferative activity against four cancer cell lines (HepG2, HCT116, MCF-7, and PC-3). Compound 5b showed good antiproliferative activity (IC50 = 20.71 μM) against MCF-7 cell lines. Molecular docking results showed that compound 5b formed hydrogen bond with Met 769 and Lys 721 and π-sulfur interaction with Met 742 of EGFR tyrosine kinase (PDB ID: 1M17). Compound 5b decreases the expression of EGFR and p-EGFR. It also induces apoptosis through reactive oxygen species generation, followed by the change in mitochondrial membrane potential.

Introduction

Cancer is one of the most devastating diseases in the developing countries.[1] The epidermal growth factor receptor (EGFR) plays an important role in cell survival, growth, differentiation, and tumorigenesis. Dysregulation of EGFR is a common mechanism in cancer progression especially in nonsmall cell lung cancer (NSCLC). Also, overexpression of EGFR has been observed in different types of cancers such as breast, ovarian, head and neck, colon, and so forth.[2] Some FDA-approved drugs, EGFR inhibitors such as erlotinib[3] (i), gefitinib[4] (ii), icotinib[5] (iii), lapatinib[6] (iv), and afatinib[7] (v), are used for the treatment of the above-mentioned cancers (Figure ). The interplay of reactive oxygen species (ROS) and the EGFR plays an important role in cancer progression. Excessive ROS can induce negative responses such as growth inhibition or death of cancer cells. Mitochondrial dysfunction is also the major mechanism inducing oxidative stress. Higher ROS levels can trigger overoxidation of the Met residue of EGFR T790M and shut down the EGFR downstream survival pathway.[8] Therefore, direct EGFR inhibition or inhibition of EGFR function via excessive ROS generation or both may be a feasible therapeutic approach for cancer treatment.

Figure 1

Chemical structure of some reported anticancer agents.

Side effects are major problems with the current EGFR inhibiting anticancer drugs. For example, erlotinib significantly reduced the levels of white blood cells, red blood cells (RBCs), and hemoglobin. It increased liver function markers, aspartate aminotransferase and alanine aminotransferase levels, and damaged the internal organs in an experimental rat model.[9] Similarly, unusual hematologic complications were detected after erlotinib was administered in patients with advanced NSCLC.[10] Therefore, it is important to design new EGFR inhibitors as anticancer agents with low toxicity on normal organs and blood cells.

Quinazoline is an important heterocyclic moiety used in drug discovery because of its diverse biological activities.[11] Especially, 4-aminoquinazoline moiety showed good efficacy against various cancers. The structure–activity relationship (SAR) of EGFR inhibitors such as erlotinib and lapatinib revealed a quinazoline moiety to play an important role in antitumor activity, especially 4-aminoquinazoline moiety. 4-Aminoquinazoline moiety seemed particularly very important for activity and showed diverse biological activities such as anticancer,[12] antitubercular,[13] antimalarial,[14] antileishmanial,[15] and antibacterial and antifungal activities.[16]

1,2,3-Triazole is another important pharmacophore in medicinal chemistry and it can form hydrogen bonding with biological targets,[17] which will be useful for the activity. Also, triazole moiety-containing molecules (vi–ix, Figure ) are known to show various pharmacological activities such as anticancer,[18] anti-human immunodeficiency virus,[19] antitubercular,[20] and anti-inflammatory[21] activities. These structural features and importance in various biological activities have made this moiety very important in drug discovery. The fight against cancer and hence the research to cure the disease are continuing since last many years. Many novel therapeutics were tried, but most of them suffer from severe toxicities. In an ongoing project in our laboratory on the discovery of new anticancer agents,[22] we were interested to make EGFR inhibitors. Recently, molecular hybridization approach has been widely used for the design and synthesis of small hybrid compounds for the treatment of cancer. The approach mainly involves combining two or more different pharmacophore moieties in a single molecule having a common scaffold. These hybrid molecules have many advantages over the conventional drugs such as toxicity,[23] solubility, multidrug resistance, and so forth. In the present study, we are using the molecular hybridization strategy to combine the biologically important two scaffolds, quinazoline and 1,2,3-triazole, to get a small set of new hybrid compounds (Figure ). As discussed earlier, both quinazoline and 1,2,3-triazole moieties are very important for the anticancer activity, thus we synthesized 20 triazole-containing quinazoline hybrid compounds and performed cytotoxicity studies and the molecular docking studies thereafter. A lead compound was used to study EGFR inhibition, ROS generation, and toxicity in normal cells as well as in blood cells.

Figure 2

Design strategy of the target molecule.

Results and Discussion

The synthesis was started by converting 4-nitro-benzylbromide 1 to the corresponding azide 2 in the presence of sodium azide in tetrahydrofuran (THF)–water in 95% yield. Compound 2 was reacted with different mono-substituted alkynes under classical “click” condition to produce different triazole compounds 3 in good yields. Finally, nitro group in 3 was reduced (Fe/NH4Cl in ethanol and water) to the corresponding amine 4, which was further coupled with different 4-chloro quinazolines to give the desired target compounds (5a–5t) in 73–88% yield (Scheme ). All compounds were fully characterized by 1H nuclear magnetic resonance (NMR), 13C NMR, Fourier transform infrared (FT-IR), and high-resolution mass spectrometry (HRMS) data.

Scheme 1

Synthetic Route of the Target Molecule and Crystal Structure of Compound 5c (ccdc: 1854806)

Reagents and conditions: (a) NaN3, THF/H2O (4:1), RT, 1 h, 95%; (b) CuI, THF, different alkynes, reflux, 80 °C, 3 h, 80–85%; (c) Fe, NH4Cl, EtOH/H2O (1:1), reflux, 80 °C, 2 h, 76–80%; (d) NaOAc, THF/H2O (4:1), different quinazolines, reflux, 80 °C, 6 h, 73–88%.

The average 50% inhibitory concentration (IC50) values (concentration needed to inhibit cancer cell line proliferation by 50%) of the compounds (5a–5t) against four human cancer cell lines that include HCT116 (human colorectal cancer cell line), HEPG2 (human liver cancer cell line), MCF-7 (human breast cancer cell line), and PC-3 (human prostate cancer cell line) were determined using the cytotoxicity assay method. The IC50 values are listed in Table , and the marketed anticancer drug erlotinib was used as positive control. On the basis of the cytotoxicity assay results, further efforts were made to elucidate the SAR. All of the synthesized compounds were screened against different cancer cell lines (HepG2, MCF-7, HCT116, and PC-3). Results suggested that most of the compounds showed moderate to good efficacy toward MCF-7 compared to other cell lines. Among all, compound 5b showed the best activity with an IC50 value of 20.71 μM in MCF-7 cell lines. Moreover, it was observed that compounds bearing the −Cl atom at the second position of quinazoline (5b, 5e, 5h, 5k, and 5n) were better compared to other substitutions. Surprisingly, all of the above-mentioned active compounds containing −OMe group at the 6, 7 position of the quinazoline moiety are resulted, strongly suggesting that the chlorine atom at the 2nd position and −OMe group at the 6, 7 position of quinazoline are necessary for the activity.

Table 1

Cytotoxicity Activities of Compounds 5a–5t against HepG2, MCF-7, HCT116, and PC-3 in Micromolar

The best compound 5b has an IC50 value of 20.71 μM, which is higher than the standard compound erlotinib (11.57 μM). Interestingly, 5b also shows lower toxicity than erlotinib on a normal human epithelial kidney cell line (40.32 ± 4.43 and 29.48 ± 3.32 μM), in human blood RBC (45.6 ± 2.65 and 16.23 ± 3.23 μM), and in human peripheral blood mononuclear cell (37.38 ± 3.55 and 20.46 ± 4.1 μM, respectively). Therefore, though compound 5b shows relatively low toxicity than erlotinib in cancer cells, it has low toxicity in normal cell lines and normal blood cells. Thus, compound 5b is expected to be a better drug candidate than erlotinib. Gratifyingly, compound 5b also has 4-amino quinazoline moiety as the pharmacophore similar to that of erlotinib and gefitinib, and we thought that compound 5b shows anticancer activity through the EGFR-mediated pathway. For this study, we selected the crystal structure (PDB ID: 1M17)[24] of EGFR tyrosine kinase for the molecular modeling study. To study the interaction between EGFR tyrosine kinase and triazole-substituted quinazoline hybrid derivatives, molecular docking of the EGFR protein (PDB ID: 1M17) and compound 5b using discovery studio software was performed. Discovery studio was used for the visualization of interaction of the target molecule with EGFR tyrosine kinase. Docking results showed that compound 5b goes and binds in the adenosine 5′-triphosphate (ATP)-binding pocket of 1M17 and showed two hydrogen bonding interactions with N1 of quinazoline with the main-chain NH group of Met 769 at a distance of 3.13 Å and triazole N2 with Lys 721 in the ATP-binding pocket at a distance of 3.04 Å. Both erlotinib and compound 5b go and bind in the same ATP-binding pocket of EGFR tyrosine kinase (1M17, Figure ).

Figure 3

(a) Surface representation of the EGFR protein (PDB ID 1M17) along with compound 5b (magenta) and erlotinib (blue). (b,c) Three-dimensional (3D) and two-dimensional (2D) representation of molecular docking interactions of compound 5b in the ATP-binding pocket of EGFR tyrosine kinase (1M17). (d,e) 3D and 2D molecular docking interactions of erlotinib in the ATP-binding pocket of EGFR tyrosine kinase.

Compound 5b also showed other interactions such as halogen interaction with Gln 767, π–alkyl interaction with Leu 694, Leu 820, and Cys 751, and π–sulfur interaction with Met 742. Erlotinib was used as the reference compound, which also formed a similar H-bond with Met 769 at a distance of 2.85 Å.

EGFR is an important signaling network in the case of cell proliferation, adhesion, migration, and survival. In order to study the mechanism of triazole-substituted quinazoline hybrids, we investigated the effect of compound 5b on the EGFR signaling pathway in MCF-7 cell lines using western blot analysis.[25] After treatment with compound 5b in MCF-7 cell lines, the level of EGFR and p-EGFR decreases with different time intervals of 12 and 24 h (Figure ). In this experiment, erlotinib was used as positive control. These results confirmed that the antiproliferative effect of compound 5b in MCF-7 cell lines is mainly due to the decrease of EGFR and phosphorylation of EGFR and its downstream process. EGFR inhibition leads to the activation of ROS generation, which leads to DNA damage and cell death. Cellular generation of ROS is an important factor of apoptotic cell death. We have examined here the status of ROS generation by compound 5b. The maximum ROS generation was observed at 24 h after the treatment of MCF-7 cells with compound 5b. Also, flow cytometric analysis revealed that the fluorescein isothiocyanate (FITC) mean intensity was 765 in control cells but 1683 in compound 5b (20.71 μM) treated cells after 24 h, indicating a shift in FITC mean intensity from the control cells to the cells treated with compound 5b. These results demonstrated that compound 5b (20.71 μM) inducing apoptosis in MCF-7 cells at 12 and 24 h might proceed via the ROS-mediated pathway.[26]

Figure 4

Western blot image of expression of EGFR and p-EGFR upon treatment with compound 5b and erlotinib (positive control).

Apoptosis is the desired way of cancer cell death. To determine the effect of compound 5b on apoptosis, fluorescence-activated cell sorting (FACS) was performed on MCF-7 cell lines treated with compound 5b at different time intervals.[27] At the initial stage of apoptosis, phosphatidyl serine is exposed from inside cell membrane to outside and this can bind with annexin V. After treatment of MCF-7 cells with compound 5b (20.71 μM) at time points (0, 12, and 24 h), MCF-7 cells were stained with annexin V-FITC and propidium iodide (PI) and monitored by flow cytometry. It was observed that early apoptosis rates increased from 5.9 to 24.6% and the late apoptosis rates increased from 0.7 to 14.2%. The results showed that compound 5b increased cellular apoptosis in a time-dependent manner (Figure ). Flow cytometric analysis of control cells revealed that 84.4% of the cell population exhibited fluorescence at the PE-Texas Red A channel, indicating a higher level of cells having a healthy ΔΨm, whereas compound 5b (20.71 μM) treated cells at 24 h revealed that 29.5% of the cell population exhibited fluorescence at the PE-Texas Red A channel, which showed a loss of ΔΨm in 54.9% of cell population after 24 h.[28] These results indicate that compound 5b might induce apoptosis by generation of ROS via the mitochondrial pathway as it leads to lowering of mitochondrial membrane potential.

Figure 5

Effect of compound 5b in (i) apoptosis induction through ROS generation, (ii) analysis of apoptosis, and (iii) apoptosis induction through the mitochondrial membrane potential assay in MCF-7 cells at different time points (0–24) h.

Conclusions

In conclusion, a series of triazole-substituted quinazoline hybrid molecules were designed and synthesized as anticancer agents. The results showed that most of the compounds had moderate to good antiproliferative effects against four different cell lines HCT116, HepG2, PC-3, and MCF-7. Among them, compound 5b showed good antiproliferative effects against MCF-7 cell lines. Molecular docking studies showed that compound 5b formed hydrogen bond with Met 769 of the EGFR protein, which regulates the conformation of EGFR which is responsible for antiproliferative activity. Compound 5b decreased the expression of EGFR and p-EGFR in MCF-7 cell lines, from which we can conclude that compound 5b exhibits antiproliferative effects in MCF-7 cell lines through the EGFR signaling pathway. Compound 5b also caused change in mitochondrial membrane potential and ROS-mediated apoptosis in MCF-7 cell lines. From the above results, it may be concluded that compound 5b acts as the EGFR inhibitor and can be used in the treatment of cancer. Further optimization of the structure to show improved EGFR inhibitory and antiproliferative activity is ongoing in the laboratory.

Experimental Section

General Remarks

All chemicals and reagents were purchased from Sigma-Aldrich. Column chromatography purifications were performed using silica gel grade 9385, 100–200 mesh, neutral alumina (Sigma). Thin-layer chromatography (TLC) was performed on silica gel 60 F254 plates with 0.20 mm thickness (Merck, Germany), which was visualized under an ultraviolet light chamber (254 and 365 nm). NMR experiments were run on Bruker Avance III 600 (600 MHz for 1H and 150 MHz for 13C). 1H NMR spectra were recorded for solution in CDCl3 or dimethyl sulfoxide (DMSO) with tetramethylsilane as the standard. Chemical shifts for 1H and 13C spectra were recorded in parts per million (ppm). Data were reported as follows: chemical shift (ppm), integrated intensity, multiplicity (indicated as s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet), and coupling constants (J) in hertz (Hz). HRMS spectra were obtained on a JEOL MS station 700 (JEOL Ltd., Akishima-Shi, Japan). The FT-IR spectra of the samples were recorded on a JASCO FT-IR 4200 spectrometer (JASCO, Easton, MD, USA) using a KBr disk technique. The spectra were recorded from 400 to 4000 cm–1. JASCO software was used for data processing. Apoptosis, ROS, and JC1 assay were performed by FACSCalibur flow cytometry (Becton Dickinson, San Jose, CA, USA).

Synthetic Procedure

General Procedure To Synthesize Compound 2

To the solution of compound 1 (1 equiv) in THF was added sodium azide (1.5 equiv) which was dissolved in water dropwise at 0 °C. The reaction mixture was then stirred for 1 h (0 °C to rt) and was monitored through TLC. After the complete consumption of the starting material, the solvent was evaporated. The crude mixture was then dissolved in EtOAc and washed with water and brine (3 × 10 mL). Thereafter, the organic layer was collected and dried over Na2SO4 and concentrated under reduced pressure to get yellow liquid in 95% yield.

General Procedure To Synthesize Compound 3

To the solution of compound 2 (1 equiv) in THF were added different acetylene (1 equiv) and copper iodide (0.2 equiv), which was heated to reflux temperature (80 °C) for 3 h. After the total consumption of the starting material (monitored through TLC), the solvent was evaporated. The reaction mixture was then diluted with ethyl acetate, filtered through a Celite bed, and washed with water and brine (3 × 10 mL) in a separating funnel. Thereafter, the organic layer was collected and dried over Na2SO4 and then evaporated under reduced pressure to get a crude solid, which was purified by column chromatography (silica gel 100–200, per ether/ethyl acetate 4:1) to afford the desired product as yellow solid with 80–85% yield.

General Procedure To Synthesize Compound 4

To the solution of compound 3 (1 equiv) in ethanol–water (1:1) were added iron powder (4 equiv) and ammonium chloride (10 equiv), which was heated to reflux temperature (80 °C) for 2 h. The reaction was monitored through TLC until total consumption of the starting material. After completion, ethanol was evaporated, and the crude mixture was diluted with ethyl acetate and passed through a Celite bed. Then, it was washed with water and brine (3 × 10 mL) in a separating funnel. Thereafter, the organic layer was collected and dried over Na2SO4 and evaporated under reduced pressure to get the crude solid. It was then purified by column chromatography (silica gel 100–200, per ether/ethyl acetate 1.5:1) to afford the desired product as yellow solid with 76–80% yield.

General Procedure To Synthesize Compound 5

To the solution of compound 4 (1 equiv) in THF/water (4:1), different substituted 4-chloro quinazoline (0.9 equiv) and anhydrous sodium acetate (3 equiv) were added. The reaction mixture was heated to reflux temperature (80 °C) for 6 h and monitored through TLC. After total consumption of the starting material, the solvent was evaporated. The residue was then dissolved in EtOAc and washed with water and brine (3 × 10 mL). The organic layer was thereafter collected and dried over Na2SO4. It was then purified by column chromatography (neutral aluminum oxide, dichloromethane/methanol 49:1) to afford the desired product in 73–88% yield as a white powder.

In similar manner, all other triazole-containing quinazoline hybrid compounds (5a–5t) were prepared.

Characterization Data

6,7-Dimethoxy-N-(4-((4-phenyl-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5a)

Yield 87% (32 mg); pale yellow solid; mp: 220–221 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.53 (s, 1H), 8.65 (s, 1H), 8.44 (s, 1H), 7.86 (d, J = 7.8 Hz, 2H), 7.82 (m, 3H), 7.44 (t, J = 6 Hz, 2H), 7.40 (d, J = 8.4 Hz, 2H), 7.33 (t, J = 7.2 Hz, 1H), 7.18 (s, 1H), 5.63 (s, 2H), 3.95 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ (ppm) 156.7, 154.7, 153.2, 149.3, 147.4, 147.1, 139.9, 131.1, 129.3, 128.7, 128.3, 125.6, 122.9, 121.8, 109.3, 107.6, 100.3, 56.6, 56.2, 53.2. IR (KBr) [cm–1] ν: 3386, 3314, 3201, 3138, 3007, 1624, 1577, 1517, 1467, 1426, 1351, 1245, 1146, 1070.41, 993, 923, 855, 763, 691, 657. HRMS (ESI-m/z): calcd for C25H22N6O2, [M + H]+ 439.1822; found, 439.1892.

2-Chloro-6,7-dimethoxy-N-(4-((4-phenyl-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5b)

Yield 82% (37 mg); white solid; mp: 292–293 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.90 (s, 1H), 8.68 (s, 1H), 7.86 (d, J = 7.2 Hz, 3H), 7.74 (d, J = 8.4 Hz, 2H), 7.43 (m, 4H), 7.33 (t, J = 7.2 Hz, 1H), 7.17 (s, 1H), 5.66 (s, 2H), 3.94 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 157.9, 155.0, 154.2, 149.0, 148.2, 146.6, 138.4, 131.7, 130.7, 128.9, 128.3, 127.9, 125.2, 122.9, 121.5, 107.2, 106.6, 102.2, 56.3, 56.0, 52.7. IR (KBr) [cm–1] ν: 3361, 3138, 2988, 2948, 1621, 1572, 1515, 1458, 1426, 1240, 1150, 1001, 963, 842, 763, 697. HRMS [EI-m/z]: calcd for C25H21N6O2Cl, [M]+ 472.1415; found, 472.14136.

N-(4-((4-Phenyl-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5c)

Yield 85% (30 mg); white solid; mp: 270–271 °C; 1H NMR (600 MHz,, DMSO-d6): δ 9.85 (s, 1H), 8.66 (s, 1H), 8.58 (s, 1H), 8.55 (d, J = 8.4 Hz, 1H), 7.87 (m, 5H), 7.79 (d, J = 8.4 Hz, 1H), 7.64 (t, J = 7.8 Hz, 1H), 7.42 (m, 4H), 7.33 (t, J = 7.2 Hz, 1H), 5.64 (s, 2H). 13C NMR (150 MHz, DMSO-d6): δ 158.1, 154.8, 150.1, 147.1, 139.6, 133.5, 131.5, 131.1, 129.3, 128.7, 128.3, 128.2, 126.7, 125.6, 123.4, 123.0, 121.8, 115.6, 53.2. IR (KBr) [cm–1] ν: 3258, 3135.49, 3087, 1611, 1570, 1524, 1501, 1415, 1357, 1224, 1074, 1043, 922.80, 766, 683, 511. HRMS [EI-m/z]: calcd for C23H18N6, [M]+ 378.1593; found, 378.15329.

N-(4-((4-(4-Ethylphenyl)-1H-1,2,3-triazol-1-yl)methyl)phenyl)-6,7-dimethoxyquinazolin-4-amine (5d)

Yield 88% (39 mg); white solid; mp: 230–231 °C; 1H NMR (600 MHz, CDCl3): δ 8.68 (s, 1H), 8.06 (d, J = 12 Hz, 1H) 7.71 (s, 1H), 7.68 (m, 4H), 7.43 (d, J = 6 Hz, 1H), 7.27 (s, 1H), 7.22 (m, 4H), 5.55 (s, 2H), 4.03 (s, 3H), 3.92 (d, J = 1.8 Hz, 3H), 2.65 (q, J = 7.8 Hz, 2H), 1.23 (t, J = 7.8 Hz, 3H). 13C NMR (150 MHz, CDCl3): δ 156.4, 154.7, 153.4, 149.6, 148.5, 147.5, 144.6, 139.3, 138.9, 129.9, 128.5, 128.4, 127.5, 125.6, 122.3, 119.6, 109.3, 107.7, 99.9, 56.3, 56.2, 53.8, 28.6, 15.4. IR (KBr) [cm–1] ν: 3379, 2956, 1623, 1577, 1516, 1462, 1423, 1394, 1240, 1140, 1061, 996, 840, 798, 540. HRMS (ESI-m/z): calcd for C27H26N6O2, [M + H]+ 466.2195; found, 467.2189.

2-Chloro-N-(4-((4-(4-ethylphenyl)-1H-1,2,3-triazol-1-yl)methyl)phenyl)-6,7-dimethoxyquinazolin-4-amine (5e)

Yield 84% (34 mg); white solid; mp: 277–278 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.89 (s, 1H), 8.61 (s, 1H), 7.85 (s, 1H), 7.76 (d, J = 8.4 Hz, 2H), 7.73 (d, J = 8.4 Hz, 2H), 7.42 (d, J = 8.4 Hz, 2H), 7.29 (d, J = 8.4 Hz, 2H), 7.16 (s, 1H), 5.64 (s, 2H), 3.94 (s, 3H), 3.91 (s, 3H), 2.61 (q, J = 7.8, 2H), 1.19 (t, J = 7.8, 3H). 13C NMR (150 MHz, DMSO-d6): δ 158.3, 155.4, 154.6, 149.5, 148.6, 147.2, 143.9, 138.9, 132.2, 128.7, 125.6, 123.4, 121.6, 107.7, 107.1, 102.6, 56.7, 56.4, 53.1, 28.3, 15.9. IR (KBr) [cm–1] ν: 3356, 2965, 1621, 1573, 1515, 1455, 1427, 1343, 1294, 1240, 1150, 1002, 962, 839, 800, 580, 530. HRMS [EI-m/z] calcd for C27H25N6O2Cl, [M]+ 500.1728; found, 500.17178.

N-(4-((4-(4-Ethylphenyl)-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5f)

Yield 87% (28 mg); white solid; mp: 250–251 °C; 1H NMR (600 MHz,, DMSO-d6): δ 9.86 (s, 1H), 8.59 (d, J = 6 Hz, 2H), 8.54 (d, J = 12 Hz, 1H), 7.88 (d, J = 6 Hz, 2H), 7.85 (d, J = 6 Hz, 1H), 7.79 (d, J = 12 Hz, 1H), 7.76 (d, J = 12 Hz, 2H), 7.64 (t, J = 12 Hz, 1H), 7.41 (d, J = 6 Hz, 2H), 7.27 (d, J = 7.8 Hz, 2H), 5.62 (s, 2H), 2.61 (q, J = 7.8 Hz, 2H), 1.19 (t, J = 7.8 Hz, 3H). 13C NMR (150 MHz, DMSO-d6): δ 158.2, 154.8, 150.1, 147.2, 143.9, 139.5, 133.5, 131.6, 128.7, 128.7, 128.6, 128.2, 126.7, 125.6, 123.4, 123.0, 121.4, 115.6, 53.2, 28.3, 15.9. IR (KBr) [cm–1] ν: 3422, 3290, 3103, 2967, 2927, 1616, 1571, 1526, 1498, 1422, 1358, 1319, 1224, 1049, 924, 830, 770, 677. HRMS [EI-m/z] calcd for C25H22N6, [M]+ 406.1915; found, 406.19156.

(1-(4-(6,7-Dimethoxyquinazolin-4-ylamino)benzyl)-1H-1,2,3-triazol-4-yl)methanol (5g)

Yield 77% (29 mg); off-white solid; mp: 295–296 °C; 1H NMR (600 MHz,, DMSO-d6): δ 9.52 (s, 1H), 8.43 (s, 1H), 8.02 (s, 1H), 7.82 (s, 1H), 7.77 (d, J = 7.8 Hz, 2H), 7.36 (d, J = 8.4 Hz, 2H), 7.18 (s, 1H), 5.55 (s, 2H), 5.18 (t, J = 5.4 Hz, 1H), 4.51 (d, J = 6 Hz, 2H), 3.95 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 156.7, 154.7, 153.2, 149.3, 148.7, 147.4, 131.3, 128.7, 123.1, 122.9, 109.3, 107.6, 102.3, 56.6, 56.2, 55.5, 52.9. IR (KBr) [cm–1] ν: 3315, 3146, 3004.33, 2928, 2834, 1623, 1579, 1517, 1466, 1425, 1246, 1140, 1050, 994, 924, 854, 779, 657, 557, 515. HRMS (ESI-m/z) calcd for C20H20N6O3, [M + H]+ 392.1675; found, 393.1675.

(1-(4-(2-Chloro-6,7-dimethoxyquinazolin-4-ylamino)benzyl)-1H-1,2,3-triazol-4-yl)methanol (5h)

Yield 74% (24 mg); light yellow solid; mp: 265–266 °C; 1H NMR (600 MHz,, DMSO-d6): δ 9.89 (s, 1H), 8.04 (s, 1H), 7.85 (s, 1H), 7.70 (d, J = 8.4 Hz, 2H), 7.38 (d, J = 8.4 Hz, 2H), 7.17 (s, 1H), 5.57 (s, 2H), 5.20 (s, 1H), 4.51 (s, 2H), 3.94 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 158.4, 155.4, 154.6, 149.5, 148.8, 148.6, 138.7, 132.4, 128.8, 123.4, 107.06, 107.04, 102.6, 56.7, 56.4, 55.5, 52.8. IR (KBr) [cm–1] ν: 3390, 3282, 3037, 3007, 2930, 1604, 1576, 1511, 1465, 1420, 1309, 1241, 1136, 1057, 992, 849, 781, 751, 726, 695. HRMS [EI-m/z] calcd for C20H19N6O3Cl, [M]+ 426.1207; found, 426.1216.

(1-(4-(Quinazolin-4-ylamino)benzyl)-1H-1,2,3-triazol-4-yl)methanol (5i)

Yield 73% (21 mg); white solid; mp: 268–269 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.84 (s, 1H), 8.58 (s, 1H), 8.54 (d, J = 8.4 Hz, 1H), 8.02 (s, 1H), 7.85 (d, J = 8.4 Hz, 3H), 7.79 (d, J = 8.4 Hz, 1H), 7.64 (t, J = 8.4 Hz, 1H), 7.37 (d, J = 8.4 Hz, 2H), 5.56 (s, 2H), 5.16 (t, J = 6 Hz, 1H), 4.51 (d, J = 6.6 Hz, 2 H). 13C NMR (150 MHz, DMSO-d6): δ 158.2, 154.8, 150.1, 148.7, 139.4, 133.5, 131.79, 128.7, 128.2, 126.7, 123.4, 123.1, 123, 115.5, 55.5, 52.8. IR (KBr) [cm–1] ν: 3433, 3308, 3129, 2923, 1604, 1576, 1532, 1426, 1402, 1364, 1325, 1229, 1128, 1049, 93, 770. HRMS [EI-m/z] calcd for C18H16N6O, [M]+ 332.1386; found, 332.13748.

6,7-Dimethoxy-N-(4-((4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5j)

Yield 87% (33 mg); white solid; mp: 224–225 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.52 (s, 1H), 8.44 (s, 1H), 8.29 (s, 1H), 7.83 (s, 1H), 7.79 (d, J = 7.8 Hz, 2H), 7.36 (d, J = 7.8 Hz, 2H), 7.29 (t, J = 7.8 Hz, 2H), 7.18 (s, 1H), 7.02 (d, J = 8.4 Hz, 2H), 6.94 (t, J = 7.2 Hz, 1H), 5.59 (s, 2H), 5.13 (s, 2H), 3.95 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 158.4, 156.7, 154.7, 153.2, 149.3, 147.4, 143.5, 139.9, 131.1, 129.9, 128.7, 124.9, 122.8, 121.2, 115.1, 109.3, 107.6, 102.2, 61.4, 56.6, 56.2, 53.0. IR (KBr) [cm–1] ν: 3375, 1621, 1575, 1514, 1461, 1421, 1237, 1137, 997, 853, 758. HRMS [EI-m/z] calcd for C26H24N6O3, [M]+ 468.1910; found, 468.1891.

2-Chloro-6,7-dimethoxy-N-(4-((4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5k)

Yield 84% (29 mg); light yellow solid; mp: 260–261 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.88 (s, 1H), 8.32 (s, 1H), 7.86 (s, 1H), 7.72 (d, J = 8.4 Hz, 2H), 7.39 (d, J = 8.4 Hz, 2H), 7.29 (t, J = 7.2 Hz, 2H), 7.17 (s, 1H), 7.03 (d, J = 7.8 Hz, 1H), 6.95 (t, J = 7.2 Hz, 2H), 5.62 (s, 2H), 5.14 (s, 2H), 3.95 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 158.4, 158.3, 155.4, 154.6, 149.4, 148.6, 143.5, 138.8, 132.1, 129.9, 128.8, 125, 123.3, 121.2, 115.1, 107.6, 107.1, 102.6, 61.4, 56.7, 56.4, 52.9. IR (KBr) [cm–1] ν: 3364, 2922, 2853, 1601, 1573, 1515, 1458, 1427, 1293, 1240, 1151, 1004, 961, 840, 758. HRMS (ESI-m/z) calcd for C26H23N6O3Cl, [M + H]+ 503.1598; found, 503.1599.

N-(4-((4-(Phenoxymethyl)-1H-1,2,3-triazol-1-yl)methyl)phenyl)quinazolin-4-amine (5l)

Yield 85% (32 mg); white solid; mp: 208–210 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.85 (s, 1H), 8.59 (s, 1H), 8.55 (d, J = 8.4 Hz, 1H), 8.29 (s, 1H), 7.87 (m, J = 6, 3H), 7.79 (d, J = 8.4 Hz, 1H), 7.64 (t, J = 13.2 Hz, 1H), 7.37 (d, J = 8.4 Hz, 2H), 7.28 (t, J = 7.2 Hz, 2H), 7.03 (d, J = 8.4 Hz, 1H), 6.94 (t, J = 7.8 Hz, 2H), 5.60 (s, 2H), 5.13 (s, 2H). 13C NMR (150 MHz, DMSO-d6): δ 158.4, 158.1, 154.8, 150.1, 143.5, 139.5, 133.52, 131.53, 129.9, 128.8, 128.2, 126.7, 124.9, 123.4, 123, 121.2, 115.5, 115.1, 61.2, 53. IR (KBr) [cm–1] ν: 3355, 3126, 2922, 1606, 1572, 1531, 1498, 1416, 1311, 1218, 1122, 1041, 828, 776, 683, 506. HRMS [EI-m/z] calcd for C24H20N6O, [M]+ 408.1703; found, 408.1703.

(6,7-Dimethoxy-quinazolin-4-yl)-[4-(4-phenylaminomethyl-[1,2,3]triazol-1-ylmethyl)-phenyl]-amine (5m)

Yield 85% (31 mg); light yellow solid; mp: 261–262 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.51 (s, 1H), 8.43 (s, 1H), 8.01 (s, 1H), 7.82 (s, 1H), 7.77 (d, J = 8.4 Hz, 2H), 7.33 (d, J = 8.4 Hz, 2H), 7.18 (s, 1H), 7.06 (t, J = 7.8 Hz, 2H), 6.62 (t, J = 7.8 Hz, 2H), 6.53 (t, J = 12 Hz, 1H), 6.02 (t, J = 6 Hz, 1H), 5.54 (s, 2H), 4.27 (d, J = 6 Hz, 2H), 3.95 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 156.7, 154.7, 153.2, 149.3, 148.8, 147.4, 146.5, 139.7, 131.2, 129.2, 128.6, 123.1, 122.8, 116.4, 112.7, 109.3, 107.6, 102.2, 56.6, 56.2, 55.3, 52.8, 39. IR (KBr) [cm–1] ν: 3390, 3282, 3037, 3007, 2930, 1604, 1576, 1511, 1465, 1420, 1309, 1241, 1136, 1057, 992, 849, 781, 751, 726, 695. HRMS (ESI-m/z) calcd for C26H25N7O2, [M + H]+ 468.2148; found, 468.2150.

(2-Chloro-6,7-dimethoxy-quinazolin-4-yl)-[4-(4-phenylaminomethyl-[1,2,3]triazol-1-ylmethyl)-phenyl]-amine (5n)

Yield 82% (29 mg); light yellow solid; mp: 280–281 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.87 (s, 1H), 8.03 (s, 1H), 7.85 (s, 1H), 7.69 (d, J = 6 Hz, 2H), 7.35 (d, J = 9 Hz, 2H), 7.17 (s, 1H), 7.06 (t, J = 8.4 Hz, 2H), 6.62 (d, J = 9.6 Hz, 2H), 6.53 (t, J = 7.2 Hz, 1H), 6.03 (t, J = 6 Hz, 1H), 5.57 (s, 2 H), 4.28 (d, J = 6.6 Hz, 2H), 3.94 (s, 3H), 3.92 (s, 3H). 13C NMR (150 MHz, DMSO-d6): δ 158.3, 155.5, 154.6, 149.4, 148.8, 148.6, 146.5, 138.7, 132.4, 129.2, 128.7, 123.4, 123.2, 116.4, 112.7, 107.6, 107.1, 102.6, 56.7, 56.4, 52.7, 39. IR (KBr) [cm–1] ν: 3406, 1603, 1572, 1513, 1426, 1241, 1150, 961, 844, 755. HRMS (ESI-m/z) calcd for C26H24N7O2Cl, [M + Na]+ 524.1578; found, 524.1586.

[4-(4-Phenylaminomethyl-[1,2,3]triazol-1-ylmethyl)-phenyl]-quinazolin-4-yl-amine (5o)

Yield 81% (29 mg); light yellow solid; mp: 250–251 °C; 1H NMR (600 MHz, DMSO-d6): δ 9.83 (s, 1H), 8.58 (s, 1H), 8.54 (d, J = 8.4 Hz, 1H), 8.01 (s, 1H), 7.86 (m, 3H), 7.79 (d, J = 8.4 Hz, 1H), 7.64 (t, J = 8.4 Hz, 1H), 7.34 (d, J = 8.4 Hz, 2H), 7.06 (t, J = 8.4 Hz, 2H), 6.62 (d, J = 7.8 Hz, 2H), 6.53 (t, J = 7.2 Hz, 1H), 6.02 (t, J = 6 Hz, 1H), 5.55 (s, 2H), 4.28 (d, J = 6 Hz, 2H). 13C NMR (150 MHz, DMSO-d6): δ 158.1, 154.8, 150.1, 148.8, 146.5, 139.4, 133.5131.7, 129.2, 128.7, 128.2, 126.7, 123.4, 123.1, 123, 116.4, 115.5, 112.7, 52.8, 39. IR (KBr) [cm–1] ν: 3422, 3289, 2923, 1604, 1571, 1524, 1498, 1414, 1357, 1316, 1256, 1123, 1051, 924, 773, 687, 510. HRMS [EI-m/z] calcd for C24H21N7, [M]+ 407.1858; found, 407.1855.

(2-Chloro-quinazolin-4-yl)-[4-(4-phenyl-[1,2,3]triazol-1-ylmethyl)-phenyl]-amine (5p)

Yield 86% (39 mg); white solid; mp: 204–206 °C; 1H NMR: (600 MHz, DMSO-d6): δ 10.25 (s, 1H), 8.68 (s, 1H), 8.55 (d, J = 8.4 Hz, 1H), 7.86 (m, 3H), 7.79 (d, J = 8.4 Hz, 2H), 7.71 (d, J = 8.4 Hz, 1H), 7.65 (t, J = 7.2 Hz, 1H), 7.43 (m, 4 H), 7.32 (t, J = 7.8 Hz, 1H), 5.65 (s, 2H). 13C NMR (150 MHz, DMSO-d6): δ 159.8, 156.6, 151.3, 147.1, 138.6, 134.6, 132.6, 131.1, 129.4, 128.8, 128.4, 127.4, 127.2, 125.6, 123.9, 123.6, 122, 114.2, 53.1. IR (KBr) [cm–1] ν: 3311, 2922, 2854, 1620, 1564, 1516, 1423, 1342, 1222, 1187, 1077, 1049, 948, 753. HRMS [ESI-m/z] calcd for C23H17N6Cl, [M + H]+ 413.1281; found, 472.1286.

(2-Chloro-quinazolin-4-yl)-{4-[4-(4-ethyl-phenyl)-[1,2,3]triazol-1-ylmethyl]-phenyl}-amine (5q)

Yield 85% (36 mg); white solid; mp: 205–207 °C; 1H NMR (600 MHz, DMSO-d6): δ 10.24 (s, 1H), 8.61 (s, 1H), 8.55 (d, J = 8.4 Hz, 1H), 7.88 (t, J = 8.4 Hz, 1H), 7.79 (d, J = 8.4 Hz, 2H), 7.76 (d, J = 8.4 Hz, 2H), 7.71 (d, J = 7.8 Hz, 1H), 7.66 (t, J = 8.4 Hz, 1H), 7.42 (d, J = 8.4 Hz, 2H), 7.26 (d, J = 7.8 Hz, 2H), 5.64 (s, 2H), 2.61 (q, J = 7.8 Hz, 2H), 1.18 (t, J = 7.8 Hz, 3H). 13C NMR (150 MHz, DMSO-d6): δ 159.8, 156.6, 151.3, 147.2, 143.9, 138.5, 134.7, 132.7, 128.8, 128.7, 128.6, 127.4, 127.1, 125.7, 123.9, 123.6, 121.6, 114.2, 53.1, 28.4, 16. IR (KBr) [cm–1] ν: 3379, 2964, 2924, 1623, 1605, 1562, 1528, 1497, 1424, 1345, 1290, 1220, 1195, 1078, 951, 839, 763. HRMS [ESI-m/z] calcd for C25H21N6Cl, [M + H]+ 441.1594; found, 441.1627.

{1-[4-(2-Chloro-quinazolin-4-ylamino)-benzyl]-1H-[1,2,3]triazol-4-yl}-methanol (5r)

Yield 83% (34 mg); white solid; mp: 224–226 °C; 1H NMR (600 MHz, DMSO-d6): δ 10.24 (s, 1H), 8.54 (d, J = 8.4 Hz, 1H), 8.04 (s, 1H), 7.88 (t, J = 7.2 Hz, 1H), 7.76 (d, J = 8.4 Hz, 2H), 7.71 (d, J = 8.4 Hz, 1H) 7.64 (t, J = 7.2 Hz, 1H), 7.38 (d, J = 8.4 Hz, 2H), 5.57 (s, 2H), 5.17 (t, J = 6 Hz, 1H), 4.5 (d, J = 4.8 Hz, 2 H). 13C NMR (150 MHz, DMSO-d6): δ 159.8, 156.6, 151.3, 148.8, 138.5, 134.6, 132.9, 128.8, 127.4, 127.2, 123.9, 123.6, 123.3, 114.2, 55.5, 52.8. IR (KBr) [cm–1] ν: 3334, 2925, 1607, 1566, 1527, 1424, 1410, 1288, 1200, 1126, 1057, 953, 859, 766. HRMS [ESI-m/z] calcd for C28H15N6OCl, [M + H]+ 367.1074; found, 367.1162.

(2-Chloro-quinazolin-4-yl)-[4-(4-phenoxymethyl-[1,2,3]triazol-1-ylmethyl)-phenyl]-amine (5s)

Yield 85% (36 mg); white solid; mp: 200–202 °C; 1H NMR (600 MHz, DMSO-d6): δ 10.25 (s, 1H), 8.56 (d, J = 8.4 Hz, 1H), 8.31 (s, 1H), 7.88 (t, J = 7.2 Hz, 1H), 7.77 (d, J = 8.4 Hz, 2H), 7.71 (d, J = 8.4 Hz, 1H), 7.65 (t, J = 8.4 Hz, 1H), 7.38 (d, J = 8.4 Hz, 2H), 7.29 (t, J = 8.4 Hz, 2H), 7.02 (d, J = 7.8 Hz, 2H), 6.93 (t, J = 7.2 Hz, 1H), 5.62 (s, 2H), 5.12 (s, 2 H). 13C NMR (150 MHz, DMSO-d6): δ 159.8, 158.5, 156.6, 151.3, 143.5, 138.5, 134.7, 132.7, 129.98, 128.9, 127.4, 127.2, 125.1, 123.9, 123.6, 121.3, 115.1, 114.2, 61.4, 52.9. IR (KBr) [cm–1] ν: 3336, 2922, 2853, 1621, 1565, 1529, 1516, 1426, 1410, 1366, 1237, 1216, 1187, 1058, 1006, 853, 760. HRMS [ESI-m/z] calcd for C24H19N6OCl, [M + H]+ 443.1387; found, 443.1450.

(2-Chloro-quinazolin-4-yl)-[4-(4-phenylaminomethyl-[1,2,3]triazol-1-ylmethyl)-phenyl]-amine (5t)

Yield 85% (36 mg); white solid; mp: 212–214 °C; 1H NMR (300 MHz, DMSO-d6): δ 10.23 (s, 1H), 8.54 (d, J = 8.1 Hz, 1H), 8.03 (s, 1H), 7.89 (t, J = 7.2 Hz, 1H), 7.74 (d, J = 8.4 Hz, 2H), 7.71 (d, J = 8.4 Hz, 1H) 7.64 (t, J = 8.4 Hz, 1H), 7.35 (d, J = 9 Hz, 2H), 7.05 (t, J = 7.2 Hz, 2H), 6.61 (d, J = 7.8 Hz, 2H), 6.52 (t, J = 7.2 Hz, 1H), 6.04 (t, J = 6 Hz, 1H), 5.56 (s, 2H), 4.27 (d, J = 6 Hz, 2H). 13C NMR (150 MHz, DMSO-d6): δ 159.8, 156.6, 151.3, 148.8, 146.5, 138.4, 134.7, 132.9, 129.3, 128.8, 127.4, 127.2, 123.9, 123.6, 123.3, 116.5, 114.2, 112.8, 52.8, 31.2. IR (KBr) [cm–1] ν: 3366, 2922, 2850, 1621, 1604, 1561, 1451, 1409, 1366, 1287, 1195, 1079, 1056, 957, 839, 765. HRMS [ESI-m/z] calcd for C24H20N7Cl, [M + H]+ 442.1547; found, 441.1564.

General Experimental Procedures for Biological Studies

Cytotoxicity Assay

Exponentially growing cells were seeded into 96-well plates at a concentration of 1 × 105 cells per well. After 24 h incubation at 37 °C, the cells were treated with all compounds in different concentrations in triplicates. The cells were incubated for another 24 h. A 20 μL of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide solution (5 mg/mL) was added to all wells and incubated for 4 h at 37 °C. The solution was discarded, and the insoluble dark blue crystals (formazan) were dissolved in 40 μL DMSO. After 15 min, the absorbance was measured using an ELISA reader at a wavelength of 595 nm. The IC50 of all compounds is the concentration (μg/mL) of the compound at which there was 50% growth inhibition with respect to the control culture in different cell lines.

Analysis of Cellular apoptosis

Apoptosis was assayed by using an annexin-V FITC apoptosis detection kit (Calbiochem, CA, USA). Briefly, cells were treated with or without the compounds in a time-dependent manner (0, 12, and 24 h) and then washed and stained with PI and annexin-V-FITC in accordance with the manufacturer’s instructions. The percentages of live, apoptotic, and necrotic cells were determined by the flow cytometric method (Becton Dickinson, San Jose, CA, USA). Data from 1 × 106 cells were analyzed for each sample.

Measurement of ROS

ROS generation was measured by dichlorofluorescein diacetate (DCF-DA). After treatment with the compounds for the time periods (0, 12, and 24 h), the cells were incubated with 10 μM DCF-DA at 37 °C for 20 min. Then cell pellets were suspended in 1 mL phosphate-buffered saline (PBS). Samples were analyzed at an excitation wavelength of 480 nm and an emission wavelength of 525 nm by FACSCalibur flow cytometry (Becton Dickinson, San Jose, CA, USA).

Measurement of Mitochondrial Membrane Potential (JC1 Assay)

MCF-7 cells were seeded for 24 h and then treated with and without compounds in a time-dependent manner (0, 12, and 24 h). Cells were washed twice with ice-cold PBS and then incubated with JC-1 dye (5 μg/mL) in darkness for 20 min at room temperature (37 °C). Emission was determined by the flow cytometric method (Becton Dickinson, San Jose, CA, USA) at 525 nm.

Western Blot

Treated or untreated cells were collected and lysed. Lysates (30 μg of protein per well) were separated by electrophoresis in 12% sodium dodecyl sulfate polyacrylamide gel and electrotransferred to poly(vinylidene difluoride) membranes using a Trans-Blot system (Trans Blot wet transfer; Bio-Rad Laboratories, Inc., Hercules, CA, USA). The membranes were blocked with 5% bovine serum albumin in TBST (tris buffered saline containing 0.1% Tween-20, pH 7.6) for 1 h at room temperature and then incubated with primary antibodies overnight at 4 °C. After washing with TBST, membranes were incubated with horseradish peroxidase conjugated secondary antibody for 1 h. Immunoreactive bands were visualized by chemiluminescence using tetramethylbenzidine as the substrate. β-Actin was used as the loading control.