Next Article in Journal
Derivation, Functionalization of (S)-Goniothalamin from Goniothalamus wightii and Their Derivative Targets SARS-CoV-2 MPro, SPro, and RdRp: A Pharmacological Perspective
Previous Article in Journal
Development of a Polymeric Membrane Impregnated with Poly-Lactic Acid (PLA) Nanoparticles Loaded with Red Propolis (RP)
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Molecules
Volume 27
Issue 20
10.3390/molecules27206960
molecules-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Design, Synthesis, Anticancer Activity and Molecular Docking of New 1,2,3-Triazole-Based Glycosides Bearing 1,3,4-Thiadiazolyl, Indolyl and Arylacetamide Scaffolds

by
Hussein H. Elganzory
1,
Fahad M. Alminderej
1,*,
Mohamed N. El-Bayaa
2,*,
Hanem M. Awad
3,
Eman S. Nossier
4 and
Wael A. El-Sayed
1,3
1
Department of Chemistry, College of Science, Qassim University, Buraidah 51452, Saudi Arabia
2
Photochemistry Department, National Research Centre, Cairo 12622, Egypt
3
Tanning Materials and Leather Technology Department, National Research Centre, El-Behouth St, Dokki, Cairo 12622, Egypt
4
Department of Pharmaceutical Medicinal Chemistry and Drug Design, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo 11754, Egypt
*
Authors to whom correspondence should be addressed.
Molecules 2022, 27(20), 6960; https://doi.org/10.3390/molecules27206960
Submission received: 14 September 2022 / Revised: 4 October 2022 / Accepted: 7 October 2022 / Published: 17 October 2022
Browse Figures
Versions Notes

Abstract

:
New 1,3,4-thiadiazole thioglycosides linked to a substituted arylidine system were synthesized via heterocyclization via click 1,3-dipolar cycloaddition. The click strategy was used for the synthesis of new 1,3,4-thiadiazole and 1,2,3-triazole hybrid glycoside-based indolyl systems as novel hybrid molecules by reacting azide derivatives with the corresponding acetylated glycosyl terminal acetylenes. The cytotoxic activities of the compounds were studied against HCT-116 (human colorectal carcinoma) and MCF-7 (human breast adenocarcinoma) cell lines using the MTT assay. The results showed that the key thiadiazolethione compounds, the triazole glycosides linked to p-methoxyarylidine derivatives and the free hydroxyl glycoside had potent activity comparable to the reference drug, doxorubicin, against MCF-7 human cancer cells. Docking simulation studies were performed to check the binding patterns of the synthesized compounds. Enzyme inhibition assay studies were also conducted for the epidermal growth factor receptor (EGFR), and the results explained the activity of a number of derivatives.

1. Introduction

The heightened global burden of cancer in recent decades has driven extensive research to discover effective and selective anticancer candidates. Because of the resistance and severe toxicity associated with current drugs, there is a great demand to provide more efficient therapeutic strategies and molecular targets [1,2].
Heterocyclic moieties bearing nitrogen atoms, such as 1,3,4-thiadiazole and 1,2,3-triazole, play a critical role in medicinal chemistry and are associated with different pharmaceutical properties, such as anticancer, antimicrobial, antidiabetic, anti-inflammatory and antihypertensive [3,4,5,6,7,8,9,10,11,12,13,14,15] effects. The reported targets (I–V, Figure 1) with these scaffolds revealed potent cytotoxic activities against various human cancer cell lines with different mechanisms, such as the inhibition of the dihydrofolate reductase enzyme and NUDT5 (Nudix Hydrolase 5) to silence hormone signaling in breast cancer [16,17,18,19].
As a privileged scaffold, indole displays a promising and leading heterocyclic nucleus that provides it with a range of attractive biological activities, chiefly antitumor ones [20]. The indole derivatives VI and VII (Figure 1) were found to exert their anticancer activities through the inhibition of cyclin-dependent kinases CDK-9 and CDK-4, respectively [21,22].
Recently, several pharmacophores containing glycoside fragments, e.g., I and V (Figure 1), have been developed and reported to have potential antitumor activity [23,24,25].
The epidermal growth factor receptor (EGFR) belongs to a fundamental subfamily of protein kinases that contains four members: EGFR (HER-1), HER-2, HER-3 and HER-4. EGFR is a crucial mediator performing a very vital role in the regulation of essential cellular processes involving proliferation, migration and survival [26]. The overexpression of EGFR is one of the most widely investigated for its role in the progression of many human solid tumors, such as breast cancer, non-small cell lung cancer and hepatocellular carcinoma [27]. In addition, the amplification of the HER-2 oncogene is detected in 15–30% of women suffering from breast cancer [28], which is regarded as the most serious subtype [29,30]. Attributable to the essential role of overactive EGFR and HER-2 tyrosine kinases, the inhibition of these enzymes is a well-known effective target for anticancer therapies [31,32]. The most representative drugs in this class are afatinib, lapatinib, gefitinib and erlotinib, which have been used clinically for targeted anticancer therapies [33]. Lately, it has been observed that the triazole glycoside VIII and the indole analog IX (Figure 2) demonstrate strong cytotoxic potency against different cancer cells through their EGFR inhibitory activity [19,34].
Molecular hybridization is an effective and simple tool to covalently merge two drug pharmacophores to obtain a single molecule [35]. Considering the facts discussed above regarding the biological significance of indole, thiadiazole, triazole and glycoside fragments (Figure 2) and upon the continuation of our research in the discovery of potent anticancer targets [36,37,38,39,40,41], it was conceived that the joining of these pharmacophores into one nucleus through a fragment-based drug design approach would develop highly potent anticancer targets. Herein, a novel series of glycosides incorporated into indole–thiadiazole–triazole bases or substituted arylacetamino–triazole hybrids were designed, synthesized and evaluated for their cytotoxic activities. A kinase inhibition assessment against EGFRWT, EGFRT790M and HER-2 was performed for the promising analogs to detect their mechanism of action. Furthermore, the apoptotic activity of the most potent derivatives was estimated by cell cycle analysis. Molecular docking at the binding sites of EGFRWT, EGFRT790M and HER-2 receptors was carried out in order to gain insight into new anticancer leads.

2. Results and Discussion

2.1. Chemistry

The synthetic strategy for the preparation of the targeted glycosides involved two different pathways to obtain two types of hybrid compounds; the first represents new glycosides of indole–thiadiazole–triazole hybrid bases, and the other is a group of substituted arylacetamino–triazole glycosides. The starting 1,3,4-thiadiazolylindole derivative 1 was prepared as previously reported [42]. The alkylation of the functionalized 1,3,4-thiadiazolylindole compound 1 with 1,2-dibromoethane afforded the alkylated derivative 2, which contains an S-substituted bromoethyl side chain, followed by azidation with sodium azide, leading to the formation of the corresponding functionalized azide derivative 3. The infrared spectra of the azide product 3 displayed the distinctive bands of the azide group, and its corresponding 1H NMR spectrum revealed the triplet signals of methylene groups in the side-chain substituent attached to the thiadiazole ring.
The synthesized azide 3 was reacted with the propargyl glycosides of the gluco- and xylopyranosyl moieties 4a,b under click conditions by a Cu-catalyzed cycloaddition reaction (CuCAAC) and resulted in the formation of the 1,2,3-triazole glycosides 5 and 6, respectively. Sodium ascorbate and copper sulfate were used for the generation of the required Cu(I) catalyst by the in situ reduction of Cu(II) in the reaction medium. Upon testing a number of solvent systems, the THF–H2O mixture (2:1) was determined to be the best medium and resulted in the formation of the targeted 1,2,3-triazole products. The other tested media systems in the click reaction were a tBuOH/H2O mixture (2:1) and a mixture of H2O/tBuOH/CH2Cl2 (1:2:8), which, after 2 days and 55 h with stirring at 60 °C, respectively, had yields lower than 52%. In the structures of the latter glycosides, the glycosyl moiety was attached to C4 of the triazole system as analogs of modified C-nucleosides. The IR spectra of compounds 5 and 6 demonstrated characteristic bands related to the carbonyl frequency in the acetate group at their known assigned values. Their 1H NMR spectra exhibited signals attributed to the sugar fragments, which were assigned to the formed β-confirmation of the triazole–sugar linkage, as indicated by the coupling constant of the anomeric proton. A deprotection reaction of the acetylated glycosides 5 and 6 was achieved under the action of a saturated ammonia solution in methanol and afforded the triazole glycosides 7 and 8 with free hydroxyl groups, which was in accord with their spectral data (Scheme 1).
The click synthetic approach was also applied for two other functionalized azide compounds, 9a,b, incorporating a substituted aryl acetamide system. Accordingly, in this way, the reaction was performed to realize the linkage of the terminal acetylenic sugar with 9a,b to obtain the 1,2,3-triazole glycosides 11–14 (Scheme 2).
1H NMR of the formed substituted glycosyl heterocycles showed all of the hydrogens in the formed compounds at their characteristic regions, revealing the β-configuration of the attachment of the sugar part. The latter triazolyl-glycosides 11–14 were hydrolyzed to afford the deacetylated derivatives 15–18, respectively, by using a methanolic ammonia solution (Scheme 2). The absorption bands characterized the hydroxyl groups of the afforded deacetylated glycosidic compounds at their characteristic regions, in addition to the disappearance of the acetyl-carbonyl absorption bands. Furthermore, the NMR spectra indicated the deacetylation process and revealed the existence of hydroxyl proton signals and the disappearance of the signals of the methyl protons of the acetyl groups. The purity of the compounds was revealed by the adequate results of the applied spectral and analytical analyses, such as 1H and 13C NMR, IR and elemental analysis, for the structural confirmation of the synthesized compounds, in addition to the TLC technique, and the proportions of the afforded products indicated a sufficient degree of purity.

2.2. Biological Evaluation

2.2.1. Cytotoxic Screening

The synthesized compounds 1–3, 5–9 and 11–18 were all examined in vitro for their cytotoxic activities against HCT-116 and MCF-7 human cancer cells using the MTT assay, and doxorubicin was applied as a reference drug. All compounds suppressed both cancer cells in a dose-dependent manner, and the results are depicted in Table 1 and Figures S1–S3 (Supplementary Data). In the case of HCT-116 human colorectal carcinoma cells, compounds 12, 8 and 15 had more potent cytotoxic activities (IC50 = 2.2, 4.6 and 11.4 µM, respectively); both compounds 11 and 7 had comparable and promising cytotoxic activities (IC50 = 15.4 and 15.5 µM, respectively), and all other compounds had significantly less cytotoxic activities (IC50 range 20.8–52.7 µM) relative to that of doxorubicin (IC50 = 12.1 µM). In the case of MCF-7 human breast cancer cells, six compounds (7, 15, 11, 3, 8 and 12) had more potent cytotoxicity (IC50 = 0.5, 0.6, 0.8, 1.1, 4.2 and 5.7 µM, respectively); three compounds (6, 5 and 2) showed promising cytotoxic potency (IC50 = 10.8, 13.9 and 14.1 µM, respectively), and the rest of the compounds had significantly less cytotoxic activities (IC50 range 18.1–35.3 µM) relative to the reference drug (IC50 = 9.4 µM).

2.2.2. Structure–Activity Relationship

The incorporation of 1-ethyl-1H-indole into 1,3,4-thiadiazol-2-thiol through the methanimine group (CH=N) in compound 1 afforded weak cytotoxic activity against HCT-116 and moderate activity (about half the activity of doxorubicin) against MCF-7 (IC50 = 46.9 ± 4.7 and 18.1 ± 2.4 µM against HCT-116 and MCF-7, respectively). The substitution of the thiol group with 2-bromoethyl afforded compound 2, with a slight improvement in the cytotoxicity against MCF-7 only (IC50 = 14.1 ± 3.1 µM), while substitution with the 2-azidoethyl moiety in compound 3 yielded excellent activity against MCF-7 and moderate activity against HCT-116 (IC50 = 1.1 ± 0.6 and 30.8 ± 4.3 µM against MCF-7 and HCT-116, respectively). A noticeable improvement in activity was observed against both screened cell lines upon substitution with acetylated 1,2,3-triazole glycosides in 6 and 5 (IC50 = 20.8 ± 2.1 and 22.6 ± 2.2 µM against HCT-116; 10.8 ± 1.5 and 13.9 ± 2.1 against MCF-7, respectively). Replacement with deacetylated N-glycosides in 7 and 8 revealed excellent and more potent cytotoxicity against both cancerous cell lines (IC50 = 15.5 ± 1.8 and 4.6 ± 0.9 µM against HCT-116; 0.5 ± 0.2 and 4.2 ± 1.1 against MCF-7, respectively).
Two series were obtained upon the fixation of the 1,2,3-triazole glycoside scaffold due to its detectable importance in the enhancement of cytotoxicity and the replacement of the 1,3,4-thiadiazol-2-yl)-1-(1-ethyl-1H-indol-3-yl)methanimine fragment in Scheme 1 with (p-fluorophenyl or p-tolyl)acetamide in Scheme 2. It was observed that the starting materials 2-azido-N-(p-fluorophenyl or p-tolyl)acetamide 9b and 9a showed weak anticancer activity (IC50 = 33.3 ± 3.9 and 42.3 ± 5.8 µM against HCT-116; 26.4 ± 3.1 and 24.1 ± 2.9 against MCF-7, respectively). The series bearing a p-tolylacetamide moiety with an electron-donating group (CH3) in 11, 12 and 15 elevated the potency over the reference against both cancer cell lines, except in 16 (IC50 range for 11, 12 and 15 from 2.2 ± 0.5 to 15.4 ± 2.1 µM against HCT-116 and from 0.6 ± 1.5 to 5.7 ±1.1 against MCF-7, respectively), while the other one bearing p-fluorophenylacetamide with an electron-withdrawing group displayed weak activity against the screened cell lines.
Finally, combined with our previous study [16], it can be concluded that the promising cytotoxic activity is attributed to the existence of the 1,2,3-triazole-deacetylated N-glycoside hybrid. Furthermore, the incorporation of indole and 1,3,4-thiadiazole scaffolds provided an opportunity for more potency, and they could be selected as leads for the discovery of anticancer agents in the future.

2.2.3. In Vitro Inhibitory Assessment of EGFRWT, EGFRT790M and HER-2

Regarding the previous cytotoxic potency, the triazole-based glycosides 7, 8, 11, 12 and 15 were chosen for further elucidation of their EGFRWT, EGFRT790M and HER-2 inhibitory activities using erlotinib as a reference drug. As illustrated in Table 2, compounds 7, 8 and 15 displayed the highest potential inhibitory activities, with IC50 ranges of 0.21–0.38, 1.50–1.95 and 2.18–2.77 µM against EGFRWT, EGFRT790M and HER-2, respectively, but they were slightly less than that of erlotinib (IC50 = 0.13, 0.62 and 1.40 µM). However, the remaining derivatives 11 and 12 exhibited a drastic decrease in the suppression effect (IC50 = 6.45 and 12.70 µM against EGFRWT; 11.80 and 15.22 µM against EGFRT790M; and 8.60 and 18. 40 µM against HER-2, respectively), which might be ascribed to a poor fit within the EGFRWT, EGFRT790M and HER-2 binding pockets.

2.2.4. Detection of Apoptosis and Cell Cycle Analysis

The annexin V/PI binding assay was carried out on derivatives 7 and 15, which showed the most potent cytotoxicity and kinase inhibitory activity, to examine their apoptotic effects on the MCF-7 cancer cells. These cells were stained with two dyes, annexin V/propidium iodide (PI), after treating them with derivatives 7 and 15 at their IC50 concentrations of 0.5 and 0.6 μM for 24 h through the flow cytometry method [43]. It was observed that there was an increase in the percentages of late apoptosis caused by the tested compounds 7 and 15 from 0.28% (control DMSO/MCF-7 cells) to 18.81% and 25.48%, respectively. Furthermore, the screened derivatives exhibited early apoptotic effects of 4.39% and 2.69% compared to 0.46% in untreated MCF-7 cells, with necrosis percentages of 11.41% and 14.28%, respectively, versus 1.25% produced by the DMSO control (Table 3) (Figures S4 and S5, Supplementary Data). The proportion of late apoptosis obtained with compounds 7 and 15 was higher than that of the early phase, leading to the induction of apoptosis and confirming the effectiveness of these derivatives in cancer therapy.
Moreover, the cessation of cell division at cell cycle checkpoints is considered one of the main roles of anticancer therapeutics [44]. The data presented in Figure 3 and Figure S5 demonstrate that there was cell accumulation at sub-G1 and S phases, with percentages of 34.61% and 43.51% in MCF-7 cells treated with compound 7 and 42.45% and 52.08% in those treated with compound 15, compared to 1.99% and 33.85% in the untreated MCF-7 cells, respectively. The previous findings clearly show that derivatives 7 and 15 triggered a significant cell cycle arrest at sub-G1 and S phases compared with the untreated MCF-7 cells.

2.3. Molecular Docking Study

Docking simulations for targets 7, 8 and 15 were performed using Molecular Operating Environment (MOE-Dock) software version 2014.0901 [45,46] to understand their binding modes within the EGFRWT, EGFRT790M and HER-2 active sites and to interpret their promising in vitro inhibitory activities. The Protein Data Bank files (PDB codes: 1M17, 3UG2 and 3RCD) were chosen and downloaded for the corresponding EGFRWT, EGFRT790M and HER-2 enzymes, respectively [46,47,48]. The native ligands erlotinib, gefitinib and TAK-285 complexed with the co-crystallized structures of these enzymes were redocked to validate the docking processes and afforded energy scores of −12.80, −11.64 and −12.33 kcal/mol, with root-mean-square deviation (RMDS) values of 0.88, 0.75 and 1.23 Å, respectively.
As previously reported [47,48,49], erlotinib and gefitinib, bearing quinazoline scaffolds, formed H-bonds between the nitrogen at p-1 and the key amino acids Met769 and Met793 within the active sites of EGFRWT and EGFRT790M, respectively. In addition, the N-1 of pyrrolo[3,2-d]pyrimidine in the ligand TAK-285 displayed hydrogen bonding with Met801 within the binding site of HER-2.
As illustrated in the docking of our targets (Figure 4, Figure 5 and Figure 6), the hydroxyl groups of the glycoside scaffolds formed H-bonds with the backbones of Met769, Met793 and Met801 within the EGFRWT, EGFRT790M and HER-2 binding pockets. Moreover, the glycoside moieties improved fixation within EGFRWT through the formation of more H-bonding with Gln767 (in 8 and 15) and Thr766 (in 15) and within EGFRT790M through H-bonding with Gln791.
Regarding the EGFRWT receptor, the thiadiazole fragments (in 7 and 8) were observed to play a vital role in binding through arene–arene interactions with Phe699. The essential amino acid Lys721 exhibited arene–cation interactions with the indole moiety in 7 and with p-tolyl and triazole centroids in 15 (Figure 4).
Within EGFRT790M (Figure 5), arene–cation interactions were illustrated between Lys745 and the indole moiety in 8 and p-tolyl in 15. However, the triazole nitrogen and oxymethyl oxygen in 7 served as H-bond acceptors with the side chain of Ser719 (distance: 3.04 and 3.24 Å, respectively).
By focusing on Figure 6, it can be noted that 15 has an improved fit within the active site of HER-2 through an additional arene–arene interaction between the p-tolyl moiety and the essential amino acid Phe864.
The superimposition patterns in Figure S6 (in Supplementary Data) demonstrate that the screened derivatives 7, 8 and 15 are well accommodated, along with the native ligands, erlotinib, gefitinib and TAK-285, within the binding pockets of EGFRWT, EGFRT790M and HER-2 through similar H-bonding with the key amino acids Met769, Met793 and Met801, respectively. In general, these results highlight targets 7, 8 and 15 as excellent leads for the discovery of promising anticancer agents through the suppression of EGFRWT, EGFRT790M and HER-2 kinases.

3. Experimental Section

3.1. General

The melting points were recorded through a Reichert Thermovar apparatus and are uncorrected. The infrared spectra were recorded using a Perkin-Elmer (model 1720) FTIR spectrometer. Nuclear magnetic resonance investigations were performed on a Bruker AC-300 or DPX-300 spectrometer (400 MHz 1H) (100 MHz 13C). The values of δppm (chemical shifts) are reported relative to TMS as a standard reference. The J values (coupling constants) are provided in Hz. The progress of the reaction was checked and guided by TLC using aluminum silica gel 60 F245. IR, 1H NMR, 13C NMR and elemental analyses were measured at the Micro Analytical Center at the Faculty of Science, Cairo University, Egypt.

3.2. Synthesis of Bromoethyl-1,3,4-Thidiazole Derivative 2 and Azide Derivative 3

N-(5-((2-Bromoethyl)thio)-1,3,4-thiadiazol-2-yl)-1-(1-ethyl-1H-indol-3-yl)methanimine (2).
A mixture of the indolyl-1,3,4-thiadiazole derivative 1 (1.44 g, 5 mmol) and NaOH (0.2 g, 5 mmol) was dissolved in a water–ethanol mixture (1:3, 20 mL) with stirring for about 20 min. The formed mixture was added dropwise to a mixture of dibromopropane (2.81, 15 mmol) and ethanol (7 mL), and stirring was continued for 2 h. The mixture was left to stand for 3 h at room temperature, and the afforded precipitate was filtered and dried to obtain the bromoethyl-1,3,4-thidiazole derivative 2.
Yield: 75%; m.p. 90–92 °C; IR (KBr) cm−1, ν: 3290 (alkyne-CH), 3105 (aromatic C-H), 1617 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.42 (t, 3H, J = 7.2 Hz, CH3), 3.48 (t, 2H, J = 6.8, CH2), 3.72 (t, 2H, J = 6.2 Hz, CH2), 4.29 (q, 2H, J = 7.2 Hz, CH2), 7.30–7.33 (dd, 1H, J = 10.4, 8.1 Hz, Ar-H), 7.61–7.64 (d, 1H, J = 7.8 Hz, Ar-H), 8.29–8.35 (dd, 2H, J = 8.1, 10.6 Hz, Ar-H), 8.87 (s, 1H, indole-H2), 9.85 (s, 1H, N=CH). 13C-NMR (DMSO-d6) δ/ppm: 15.0 (CH3), 33.2, 33.9 (2CH2-N), 41.2 (CH2), 111.1, 113.3, 120.8, 122.5, 123.7, 125.0, 130.7, 140.1, 144.9, 145.2 (Ar-C), 162.5 (C=N). Analysis calcd. for C15H15BrN4S2 (395.34): C, 45.57; H, 3.82; N, 14.17. Found: C, 45.41; H, 3.91; N, 14.07%.
N-(5-((2-Azidoethyl)thio)-1,3,4-thiadiazol-2-yl)-1-(1-ethyl-1H-indol-3-yl)methanimine (3).
Yield: 85%; m.p. 101–102 °C; IR (KBr) cm−1, ν: 3289 (alkyne-CH), 3101 (aromatic C-H), 2100 (N=N=N), 1626 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.39 (t, 3H, J = 6.8 Hz, CH3), 3.45 (t, 2H, J = 7.2 Hz, CH2), 4.17–4.29 (m, 4H, 2CH2), 7.28–7.34 (m, 2H, Ar-H), 7.64 (d, 1H, J = 7.8 Hz, Ar-H), 8.20 (d, 1H, J = 10.8, 8.1 Hz, Ar-H), 8.86 (s, 1H, indole-H2), 9.88 (s, 1H, N=CH). 13C-NMR (DMSO-d6) δ/ppm: 15.1 (CH3), 33.1, 33.9 (2CH2-N), 41.3 (CH2), 111.1, 113.3, 120.7, 122.4, 123.7, 125.1, 130.7, 140.1, 144.9, 145.1 (Ar-C), 162.4 (C=N). Analysis calcd. for C15H15N7S2 (357.45): C, 50.40; H, 4.23; N, 27.43. Found: C, 50.56; H, 4.12; N, 27.60.%.

3.3. Synthesis of Acetylated O-Glycosides (5,6)

1-(1-Ethyl-1H-indol-3-yl)-N-(5-((2-(4-((O-acetyl-D-glycopyranosyl)oxymethyl)-1H-1,2,3-triazol-1-yl)ethyl)thio)-1,3,4-thiadiazol-2-yl)methanimine (5,6).
To a well-stirred mixture of the acetylated acetylenic gluco- or xylopyranosyl sugar (2 mmol) and the azidothio thiadiazole derivative 3 (2 mmol) in THF–H2O (2:1; 25 mL) was added CuSO4·5H2O (0.4 mmol), followed by sodium ascorbate (0.4 mmol) and a few drops of diisopropylethylamine at 0 °C. The reaction mixture was stirred at room temperature for 2 h and then at 60 °C for 6 h (TLC, petroleum ether–EtOAc, 3:1). Ethyl acetate (30 mL) was added, and the organic layer was separated, washed with water (2 × 40 mL) and dried. The residue was purified by column chromatography (petroleum ether–EtOAc, 4:1) to afford the acetylated glycosyl triazole compounds 5 and 6, respectively.
1-(1-Ethyl-1H-indol-3-yl)-N-(5-((2-(4-({[2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)ethyl)thio)-1,3,4-thiadiazol-2-yl)methanimine (5).
Yield: 79%; m.p. 131–132 °C; IR (KBr) cm−1, ν: 3279 (alkyne-CH), 3090 (aromatic C-H), 1738 (C=O), 1612 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.40 (t, 3H, J = 7.2 Hz, CH3), 1.98, 1.99, 2.01, 2.17 (4s, 12H, CH3CO), 3.59 (t, 2H, J = 7.2 Hz, CH2), 3.72 (m, 3H, CH2, H-5′), 4.02 (dd, 1H, J = 6.9 Hz, H-6′′), 4.14–4.16 (m, 1H, H-6′), 4.19–4.23 (q, 2H, J = 7.2 Hz, CH2), 4.25–4.33 (m, 1H, H-4′), 4.99–5.11 (m, 1H, H-2′), 5.34 (t, 1H, H-3′), 4.63 (s, 2H, CH2), 6.07 (d, 1H, J = 8.4 Hz, H-1′), 7.29 (s, 1H, triazole-H), 7.29 (d, 1H, J = 8.1 Hz, Ar-H), 7.62 (d, 1H, J = 7.8 Hz, Ar-H), 8.28–8.35 (m, 2H, Ar-H), 8.87 (s, 1H, indole-H2), 9.90 (s, 1H, N=CH).13C-NMR (DMSO-d6) δ/ppm: 14.9, 20.2, 20.3, 20.4, 20.6 (5CH3), 33.1, 33.9 (2CH2-N), 41.3 (CH2), 61.2 (CH2), 61.2 (C-6), 67.3 (C-4), 68.7 (C-2), 69.1 (C-3), 88.2 (C-5), 90.3 (C-1), 111.1, 113.3, 120.5, 122.5, 123.8, 125.0, 137.2, 140.1, 143.6, 144.4 (Ar-C, triazole-2C,), 162.4 (C=N). 164.2, 169.0, 169.1, 169.5, 169.6, 170.0 (4C=O, thiadiazole-C2,C5). Analysis calcd. for C32H37N7O10S2 (743.81): C, 51.67; H, 5.01; N, 13.18. Found: C, 51.48; H, 5.11; N, 13.31.%.
1-(1-Ethyl-1H-indol-3-yl)-N-(5-((2-(4-({[2,3,4-tri-O-acetyl-β-D-xylopyranos-yl]oxy}methyl)-1H-1,2,3-triazol-1-yl)ethyl)thio)-1,3,4-thiadiazol-2-yl)methanimine (6).
Yield: 68%; m.p. 136–138 °C; IR (KBr) cm−1, ν: 3278 (alkyne-CH), 3092 (aromatic C-H), 1740 (C=O) 1620 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.43 (t, 3H, J = 7.1 Hz, CH3), 1.97, 1.99, 2.01 (3s, 9H, CH3CO), 3.52 (t, J = 7.4 Hz, 2H, CH2), 3.72 (t, 2H, J = 7.4 Hz, CH2), 3.93–3.96 (dd, 1H, J = 11.6, 2.8 Hz, H-5′′), 4.25 (m, 3H, CH2, H-5′), 4.63 (s, 2H, CH2), 4.79 (dd, 1H, J = 10.6, 7.8 Hz, H-4′), 4.84 (dd, 1H, J = 10.2, 7.8 Hz, H-2′), 5.19 (t, J = 7.8 Hz, 1H, H-3′), 6.01 (d, 1H, J = 10.2 Hz, H-1′), 7.24 (s, 1H, triazole-H), 7.30–7.33 (m, 1H, Ar-H), 7.63–7.66 (m, 1H, Ar-H), 7.90 (d, 1H, J = 7.7 Hz, Ar-H), 8.01 (d, 1H, J = 8.2 Hz, Ar-H), 8.18 (s, 1H, indole-H2), 9.59 (s, 1H, N=CH). 13C-NMR (DMSO-d6) δ/ppm: 14.9, 20.1, 20.3, 20.5 (4CH3), 33.2, 33.8 (2CH2-N), 41.3 (CH2), 61.1 (CH2), 67.4 (C-5), 68.6 (C-4), 69.1 (C-2), 88.1 (C-3), 89.9 (C-1), 111.2, 113.5, 120.5, 122.3, 123.9, 125.1, 137.7, 140.1, 143.4, 144.8 (Ar-C, triazole-2C,), 162.4 (C=N). 164.3, 169.1, 169.2, 169.6, 170.1 (3C=O, thiadiazole-C2,C5). Analysis calcd. for C29H33N7O8S2 (671.74): C, 51.85; H, 4.95; N, 14.60. Found: C, 51.66; H, 5.03; N, 14.43.%.

3.4. Synthesis of Deacetylated O-Glycosides (7,8)

The acetylated 1,2,3-triazole glycoside 5 or 6 (5 mmol) was added to a saturated methanolic ammonia solution (15 mL) at 0 °C and stirred for 20 min, followed by stirring at room temperature for 7 h. After the completion of the deacetylation process (TLC, petroleum ether–hexane, 2:1), the solvent was evaporated under reduced pressure at 40 °C to afford a yellowish residue. Trituration with cold diethyl ether (20 mL) upon stirring afforded a solid, which was filtered off, dried and crystallized from ethanol to yield compound 7 or 8, respectively.
1-(1-Ethyl-1H-indol-3-yl)-N-(5-((2-(4-({[β-D-glucopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)ethyl)thio)-1,3,4-thiadiazol-2-yl)methanimine (7).
Yield: 65%; m.p. 210–213 °C; IR (KBr) cm−1, ν: 3455–3425 (OH), 3072 (C-H), 2958 (C-H), 1618 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.41 (t, 3H, J = 7.2 Hz, CH3), 3.24 (t, 2H, J = 7.4 Hz, CH2), 3.45–3.49 (m, 2H, H-6′,6′′), 3.66–3.69 (m, 1H, H-5′), 3.87 (t, 2H, CH2), 3.96–4.14 (m, 2H, H-4′,3′), 4.29 (q, 2H, J = 7.2 Hz, CH2), 4.52–4.64 (m, 2H, OH, H-2′), 4.79 (s, 2H, CH2), 5.01–5.05 (m, 1H, OH), 5.25–5.28 (m, 1H, OH), 5.35–5.39 (m, 1H, OH), 5.90 (d, 1H, J = 10.2 Hz, H-1′), 7.28–7.30 (m, 2H, Ar-H), 7.61 (d, 1H, J = 8.1 Hz, Ar-H), 8.08 (d, 1H, J = 7.7 Hz, Ar-H), 8.18 (s, 1H, triazole-H), 8.33 (s, 1H, N=CH), 9.88 (s, 1H, indole-H2). 13C-NMR (DMSO-d6) δ/ppm: 15.4 (CH3), 33.1, 33.9 (2CH2-N), 41.3 (CH2), 61.2 (CH2), 62.1 (C-6), 69.9 (C-4), 72.5 (C-2), 77.4 (C-3), 80.4 (C-5), 87.8 (C-1), 111.4, 117.5, 121.4, 122.9, 123.3, 123.9, 125.1, 137.1, 140.5, 142.8 (Ar-C, triazole-C4,C5,), 162.4 (C=N), 164.2, 164.3 (thiadiazole-C2,C5). Analysis calcd. for C24H29N7O6S2 (575.66): C, 50.08; H, 5.08; N, 17.03. Found: C, 50.23; H, 4.98; N, 17.12%.
1-(1-Ethyl-1H-indol-3-yl)-N-(5-((2-(4-({[β-D-Xylopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)ethyl)thio)-1,3,4-thiadiazol-2-yl)methanimine (8).
Yield: 68%; m.p. 203–204 °C; IR (KBr) cm−1, ν: 3455–3425 (OH), 3070 (C-H), 1618 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.41 (t, 3H, J = 7.0 Hz, CH3), 3.42 (t, 2H, J = 7.4 Hz, CH2), 3.69 (dd, 1H, J = 11, 5.3 Hz, H-5′′), 4.05–4.15 (m, 3H, H-5′, CH2), 4.17–4.22 (m, 1H, H-4′), 4.29 (q, 2H, J = 7.0 Hz, CH2), 4.63 (s, 2H, CH2), 4.87–4.91 (m, 2H, H-2′, OH), 4.91–4.94 (m, 1H, OH), 5.12–5.15 (m, 1H, OH), 5.29 (dd, 1H, J = 7.7, 5.0 Hz, H-3′), 5.90 (d, 1H, J = 5.1 Hz, H-1′), 7.24–7.27 (m, 1H, Ar-H), 7.30–7.33 (m, 1H, Ar-H), 7.61 (d, 1H, J = 8.1 Hz, Ar-H), 8.09 (d, 1H, J = 7.6 Hz, Ar-H), 8.21 (s, 1H, triazole-H), 8.33 (s, 1H, indole-H2), 9.88 (s, 1H, N=CH). 13C-NMR (DMSO-d6) δ/ppm: 15.4 (CH3), 33.1, 33.9 (2CH2-N), 41.3 (CH2), 61.2 (CH2), 69.7 (C-4), 72.8 (C-2), 77.6 (C-3), 80.5 (C-5), 87.2 (C-1), 111.2, 117.8, 121.5, 122.9, 123.1, 123.9, 125.5, 137.3, 140.6, 142.8 (Ar-C, triazole-C4,C5), 162.4 (C=N), 164.2, 164.3 (thiadiazole-C2,C5). Analysis calcd. for C23H27N7O5S2 (545.63): C, 50.63; H, 4.99; N, 17.97. Found: C, 50.46; H, 5.11; N, 18.09%.
2-(4-({[O-Acetyl-β-D-glycopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(aryl)acetamide (11–14).

3.5. Synthesis of Acetylated O-Glycosides 11–14

The same procedure for the preparation of 5 and 6 was applied. To a well-stirred mixture of the acetylated acetylenic xylo- or galactopyranosyl sugar (2 mmol) and the azide 9a,b (2 mmol) in THF–H2O (2:1; 25 mL) was added CuSO4·5H2O (0.4 mmol), followed by sodium ascorbate (0.4 mmol) and a few drops of diisopropylethylamine at 0 °C. The reaction mixture was stirred at room temperature for 1 h and then at 60 °C for 8 h (TLC, petroleum ether–EtOAc, 3:1). Ethyl acetate (35 mL) was added, and the organic layer was separated, washed with water (2 × 45 mL) and dried. The residue was purified by column chromatography (petroleum ether–EtOAc, 5:1) to afford the acetylated 1,2,3-triazole-glycosides 11–14, respectively.
2-(4-({[2,3,4-Tri-O-acetyl-β-D-xylopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(p-tolyl)acetamide (11).
Yield: 71%; m.p. 95–96 °C; IR (KBr) cm−1, ν: 3150 (NH), 3094 (aromatic C-H), 1742 (C=O), 1668 (C=O), 1618 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 2.00, 2.02, 2.04 (3s, 9H, CH3CO), 2.29 (s, 3H, CH3), 4.14 (dd, 1H, J = 11.7, 5.4 Hz, H-5′′), 4.67 (dd, 1H, J = 6.6, 11.7 Hz, H-5′), 4.33 (s, 2H, CH2), 4.77 (dd, 1H, J = 22.9, 9.4 Hz, H-4′), 4.95–4.98 (m, 1H, H-2′), 5.27 (t, 1H, J = 8.3 Hz, H-3′), 5.47 (s, 2H, CH2), 5.97 (d, 1H, J = 3.6 Hz, H-1′), 7.11 (d, 2H, J = 8.2 Hz, Ar-H), 7.33 (d, 2H, J = 8.2 Hz, Ar-H), 8.06 (s, 1H, triazole), 10.01 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 20.2, 20.3, 20.4, 20.5 (4CH3), 51.3, 61.4 (2CH2), 66.3 (C-5), 66.6 (C-4), 67.2 (C-2), 68.1 (C-3), 88.6 (C-1), 119.2, 119.3, 129.1, 129.2, 133.6, 134.4, 135.8, 142.1 (Ar-C, triazole-C4,C5), 164.9, 169.4, 169.7, 169.9 (4C=O). Analysis calcd. for C23H28N4O9 (504.50): C, 54.76; H, 5.59; N, 11.11. Found: C, 54.63; H, 5.51; N, 11.19.%.
2-(4-({[2,3,4,6-Tetra-O-acetyl-β-D-galactopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(p-tolyl)acetamide (12).
Yield: 64%; m.p. 98–99 °C; IR (KBr) cm−1, ν: 3155 (NH), 3093 (aromatic C-H), 1739 (C=O), 1668 (C=O), 1620 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.96, 1.98, 2.00, 2.02 (4s, 12H, CH3CO), 2.25 (s, 3H, CH3), 3.72–4.75 (m, 1H, H-5′), 4.00–4.03 (m, 1H, H-6′′), 4.04–4.07 (m, 1H, H-6′), 4.63 (s, 2H, CH2), 5.09–5.14 (m, 1H, H-4′), 5.27–5.31 (dd, 1H, J = 9.4, J = 10.2, H-2′), 5.43 (t, 1H, J = 9.4 Hz, H-3′), 5.44 (s, 2H, CH2), 6.02 (d, 1H, J = 10.2 Hz, H-1′), 7.12 (d, 2H, J = 8.2 Hz, Ar-H), 7.46 (d, 2H, J = 8.2 Hz, Ar-H), 8.06 (s, 1H, triazole), 10.01 (brs, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 20.1, 20.2, 20.3, 20.4, 20.5 (5CH3), 51.1, 61.2 (2CH2), 66.1 (C-6), 66.2 (C-5), 66.7 (C-4), 67.3 (C-2), 68.3 (C-3), 88.7 (C-1), 119.1, 119.2, 129.1, 129.2, 132.6, 134.5, 135.8, 142.3 (Ar-C, triazole-2C,), 165.9, 169.0, 169.4, 169.7, 169.9 (5C=O). Analysis calcd. for C26H32N4O11 (576.56): C, 54.16; H, 5.59; N, 9.72. Found: C, 54.29; H, 5.49; N, 9.86.%.
2-(4-({[2,3,4-Tri-O-acetyl-β-D-xylopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(4-fluorophenyl)acetamide (13).
Yield: 73%; m.p. 142–144 °C; IR (KBr) cm−1, ν: 3148 (NH), 3094 (aromatic C-H), 1738 (C=O), 1668 (C=O), 1615 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.97, 1.98, 2.13 (3s, 9H, CH3CO), 4.14 (dd, 1H, J = 10.6, 3.8 Hz, H-5′′), 4.37 (dd, 1H, J = 3.8, 9.8 Hz, H-5′), 4.67 (s, 2H, CH2-O), 4.76 (dd, 1H, J = 8.5, 9.8 Hz, H-4′), 4.77- 4.82 (dd, 1H, J = 10.2, 8.8 Hz, H-2′), 5.17 (t, J = 8.8 Hz, 1H, H-3′), 5.29 (s, 2H, CH2-N), 6.16 (d, 1H, J = 10.2 Hz, H-1′), 7.14 (d, 2H, J = 8.0 Hz, Ar-H), 7.55 (d, 2H, J = 8.2 Hz, Ar-H), 8.06 (s, 1H, triazole), 10.52 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 20.0, 20.1, 20.3 (3CH3), 51.9, 61.4 (2CH2), 67.7 (C-5), 68.4 (C-4), 70.2 (C-2), 77.5 (C-3), 99.1 (C-1), 115.2, 120.3, 121.2, 125.7, 130.3, 134.4, 142.9, 159.8 (Ar-C, triazole-2C,), 163.9, 169.1, 169.6, 169.7 (4C=O). Analysis calcd. for C22H25FN4O9 (508.46): C, 51.97; H, 4.96; N, 11.02. Found: C, 52.11; H, 5.09; N, 10.88.%.
2-(4-({[2,3,4,6-Tetra-O-acetyl-β-D-galactopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(4-fluorophenyl)acetamide (14).
Yield: 77%; m.p. yellowish foam; IR (KBr) cm−1, ν: 3190 (NH), 3099 (aromatic C-H), 1740 (C=O) 1666 (C=O), 1616 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 1.98, 1.99, 2.01, 2.11 (4s, 12H, CH3CO), 3.70–3.73 (m, 1H, H-5′), 4.03 (dd, 1H, J = 11.6, 2.8 Hz, H-6′′), 4.09–4.11 (m, 1H, H-6′), 4.67 (s, 2H, CH2-O), 4.70–4.74 (m, 1H, H-4′), 4.82–4.85 (dd, 1H, J = 10.2, 8.8 Hz, H-2′), 5.26 (t, 1H, J = 8.8 Hz, H-3′), 5.32 (s, 2H, CH2-N), 6.02 (d, 1H, J = 10.2 Hz, H-1′), 7.17 (d, 2H, J = 8.2 Hz, Ar-H), 7.59 (d, 2H, J = 8.2 Hz, Ar-H), 8.08 (s, 1H, triazole), 10.50 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 20.1, 20.2, 20.3, 20.4 (4CH3), 51.8, 61.6 (2CH2), 66.4 (C-6), 67.9 (C-5), 68.3 (C-4), 70.1 (C-2), 77.8 (C-3), 99.1 (C-1), 115.5, 120.1, 121.7, 125.7, 130.3, 134.8, 142.9, 159.8 (Ar-C, triazole-C4,C5), 164.2 (C=O). 169.4, 169.6, 169.7, 169.9 (C=O). Analysis calcd. for C25H29FN4O11 (580.52): C, 51.72; H, 5.03; N, 9.65. Found: C, 51.56; H, 4.91; N, 9.79.%.

3.6. Synthesis of Deacetylated O-Glycosides 15–18

2-(4-({[β-D-Xylopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(p-tolyl)acetamide (15).
Yield: 76%; m.p. 193–194 °C; IR (KBr) cm−1, ν: 3438–3455 (OH), 3200 (NH), 3094 (aromatic C-H), 1660 (C=O), 1615 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 2.24 (s, 3H, CH3), 3.34–3.37 (m, 2H, H-5′′, H-5′), 3.92–3.95 (m, 1H, H-4′), 4.28- 4.31 (m, 1H, H-3′), 4.35 (s, 2H, CH2), 4.88 (m, 2H, H-2′, OH), 4.98–5.01 (m, 1H, OH), 5.14–5.17 (m, 1H, OH), 5.30 (s, 2H, CH2), 5.72 (d, 1H, J = 3.6 Hz, H-1′), 7.12 (d, 2H, J = 8.2 Hz, Ar-H), 7.46 (d, 2H, J = 8.2 Hz, Ar-H), 8.11 (s, 1H, triazole), 10.40 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 20.5 (CH3), 52.2, 61.5 (2CH2), 65.8 (C-5), 69.6 (C-4), 73.3 (C-2), 76.5 (C-3), 102.9 (C-1), 119.2, 119.3, 125.9, 129.3, 132.8, 135.9, 143.5, 164.1 (Ar-C, triazole-C4,C5), 171.8 (C=O). Analysis calcd. for C17H22N4O6 (378.39): C, 53.96; H, 5.86; N, 14.81. Found: C, 54.09; H, 5.80; N, 15.01.%.
2-(4-({[β-D-Galactopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(p-tolyl)acetamide (16).
Yield: 75%; m.p. 199–200 °C; IR (KBr) cm−1, ν: 3448–3430 (OH), 3198 (NH), 3095 (aromatic C-H), 1660 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 2.25 (s, 3H, CH3), 3.39–3.42 (m, 2H, H-6′′, H-6′), 3.79–3.81 (m, 1H, H-5′), 4.18–4.33 (m, 3H, CH2, H-4′), 4.77–4.81 (m, 2H, H-3′, OH), 4.99–5.08 (m, 2H, H-2′, OH), 5.12–5.15 (m, H, OH), 5.25–5.28 (m, 3H, OH, CH2), 5.80 (d, 1H, J = 10.2 Hz, H-1′), 7.12 (d, 2H, J = 8.2 Hz, Ar-H), 7.45 (d, 2H, J = 8.2 Hz, Ar-H), 8.11 (s, 1H, triazole), 10.40 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 21.3 (CH3), 52.1, 61.4 (2CH2), 64.5 (C-6), 66.8 (C-5), 68.6 (C-4), 74.3 (C-2), 76.5 (C-3), 103.9 (C-1), 119.1, 119.8, 126.9, 129.3, 133.8, 135.9, 144.5, 165.1 (Ar-C, triazole-C4,C5), 170.8 (C=O). Analysis calcd. for C18H24N4O7 (408.41): C, 52.94; H, 5.92; N, 13.72. Found: C, 53.17; H, 6.11; N, 13.51.%.
2-(4-({[β-D-Xylopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(4-fluorophenyl)acetamide (17).
Yield: 51%; m.p. 197–198 °C; IR (KBr) cm−1, ν: 3480–3465 (OH), 3210 (NH), 3097 (aromatic C-H), 1661 (C=O), 1612 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 3.37–3.41 (m, 2H, H-5′′, H-5′), 3.90–3.93 (m, 1H, H-4′), 4.22–4.25 (m, 1H, H-3′), 4.32 (s, 2H, CH2), 4.85–4.88 (m, 1H, H-2′), 4.98–5.02 (m, 1H, OH), 5.12–5.15 (m, 1H, OH), 5.29 (s, 2H, CH2), 5.37–5.40 (m, 1H, OH), 5.77 (d, 1H, J = 9.8 Hz, H-1′), 7.14 (d, 2H, J = 8.2 Hz, Ar-H), 7.57 (d, 2H, J = 8.2 Hz, Ar-H), 8.09 (s, 1H, triazole), 10.52 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 51.9, 61.3 (2CH2), 65.5 (C-5), 69.4 (C-4), 73.1 (C-2), 76.3 (C-3), 102.7 (C-1), 115.1, 121.1, 125.7, 134.5, 143.4, 156.6, 159.8, 164.1 (Ar-C, triazole-C4,C5), 172.1 (C=O). Analysis calcd. for C16H19FN4O6 (382.35): C, 50.26; H, 5.01; N, 14.65. Found: C, 50.39; H, 4.89; N, 14.54.%.
2-(4-({[β-D-Galactopyranosyl]oxy}methyl)-1H-1,2,3-triazol-1-yl)-N-(4-fluorophenyl)acetamide (18).
Yield: 45%; m.p. Brownish foam; IR (KBr) cm−1, ν: 3455–3430 (OH), 3200 (NH), 3093 (aromatic C-H), 1663 (C=O), 1615 (C=N); 1H-NMR (DMSO-d6) δ/ppm: 3.37–3.41 (m, 2H, H-6′′, H-6′), 3.88–3.91 (m, 1H, H-5′), 3.99–4.02 (m, 1H, H-4′), 4.18- 4.22 (m, 1H, H-3′), 4.34 (s, 2H, CH2), 4.79–4.89 (m, 2H, OH, H-2′), 4.99–5.02 (m, 1H, OH), 5.25–5.30 (m, 2H, 2OH), 5.30 (s, 2H, CH2), 5.80 (d, 1H, J = 9.8 Hz, H-1′), 7.13 (d, 2H, J = 8.2 Hz, Ar-H), 7.46 (d, 2H, J = 8.2 Hz, Ar-H), 8.10 (s, 1H, triazole), 10.50 (s, 1H, NH). 13C-NMR (DMSO-d6) δ/ppm: 51.8, 61.6 (2CH2), 65.5 (C-6), 67.9 (C-5), 69.4 (C-4), 72.2 (C-2), 77.4 (C-3), 103.1 (C-1), 116.2, 120.5, 121.9, 126.7, 131.3, 133.4, 144.9, 159.7 (Ar-C, triazole-C4,C5), 164.9 (C=O). Analysis calcd. for C17H21FN4O7 (412.37): C, 49.51; H, 5.13; N, 13.59. Found: C, 49.35; H, 5.20; N, 13.68.%.

4. Materials and Methods

4.1. In Vitro Cytotoxic Activity

HCT-116 (human colorectal carcinoma) and MCF-7 (human breast adenocarcinoma) cell lines were purchased from the American Type Culture Collection (Rockville, MD, USA) and maintained in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10% heat-inactivated fetal bovine serum (FBS), 100 U mL−1 penicillin and 100 U mL−1 streptomycin. The cells were grown at 37 °C in a humidified atmosphere of 5% CO2.

4.2. MTT Cytotoxicity Assay

Cytotoxicity activity against HCT-116 and MCF-7 was estimated by the 3-[4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. This test is based on MTT cleavage by mitochondrial dehydrogenases from viable cells [50,51,52]. Cells were placed in a 96-well sterile microplate (5 × 104 cells well−1) and incubated at 37 °C in serum-free media containing dimethyl sulfoxide (DMSO) and either a series of various concentrations of each compound or doxorubicin (positive control) for 48 h before the MTT assay. After incubation, the media were removed, and 40 µL of MTT (2.5 mg mL−1) was added to each well. Incubation was resumed for an additional 4 h. The purple formazan dye crystals were solubilized with 200 µL DMSO. Absorbance was measured at 590 nm in a Spectra Max Paradigm Multi-Mode microplate reader (Molecular Devices, LLC, San Jose, CA, USA). Relative cell viability was expressed as the mean percentage of viable cells compared to the untreated control cells.

4.3. Statistical Analysis

All experiments were conducted in triplicate and repeated on three different days. All values are reported as mean ± SD. IC50 values were determined by SPSS Inc. probit analysis (IBM Corp., Armonk, NY, USA).

4.4. EGFRWT, EGFRT790M and HER-2 Inhibition Assessment

The promising cytotoxic targets 7, 8, 11, 12 and 15 were assessed for their in vitro inhibitory activity against EGFRWT, EGFRT790M and HER-2 kinases. Erlotinib was used as a reference following the previously described method [53]. A homogeneous time-resolved fluorescence (HTRF) assay was applied in this test (Sigma). Firstly, EGFRWT, EGFRT790M and HER-2 and their substrates were incubated with the tested compounds in enzymatic buffer for 5 min. ATP (1.65 μM) was added to the reaction mixture to start the enzymatic reaction. The assay was conducted for 30 min at room temperature. The reaction was stopped by the addition of detection reagents that contained EDTA. The detection step continued for 1 h, and then the IC50 values were determined using GraphPad Prism 5.0. Three independent experiments were performed for each concentration.

4.5. Detection of Apoptosis and Cell Cycle Analysis

Apoptosis investigation and cell cycle analysis were performed by flow cytometry [43,44]. MCF-7 cells were seeded at 8 × 104 and incubated at 37 °C in 5% CO2 overnight. After treatment with the tested compounds 7 and 15 for 24 h, cell pellets were collected and centrifuged (300 g, 5 min). For cell cycle analysis, cell pellets were fixed with 70% ethanol on ice for 15 min and collected again. The pellets were incubated with propidium iodide (PI) staining solution at room temperature for 1 h and analyzed with a Gallios flow cytometer (Beckman Coulter, Brea, CA, USA). Apoptosis detection was carried out by the FITC AnnexinV/PI commercial kit (Becton Dickenson, Franklin Lakes, NJ, USA) following the manufacturer’s protocol. The samples were analyzed by fluorescence-activated cell sorting (FACS) with a Gallios flow cytometer (Beckman Coulter, Brea, CA, USA) within 1 h after staining. Data were analyzed using Kaluza v 1.2 (Beckman Coulter).

5. Molecular Docking Study

The interactions of the newly synthesized targets 7, 8 and 15, illustrating the highest EGFRWT, EGFRT790M and HER-2 inhibitory activities, were examined and docked within the active sites of the target enzymes to study their binding modes and orientations using PDB IDs: 1M17, 3UG2 and 3RCD, respectively [47,49], using MOE-Dock software version 2014.0901 [45,46]. The 2D structures of the newly synthesized triazole-based glycosides 7, 8 and 15 were drawn using Chem. Draw. The protonated 3D structure was employed using standard bond lengths and angles. Then, geometry optimization and energy minimization were applied to obtain the Conf Search module in MOE, and the MOE file was then saved for the subsequent docking process. The co-crystallized structures of EGFRWT, EGFRT790M and HER-2 with their ligands, erlotinib, gefitinib and TAK-285, were downloaded (PDB codes: 1M17, 3UG2 and 3RCD, respectively) from the Protein Data Bank. All minimizations were performed using MOE until reaching an RMSD gradient of 0.05 kcal∙mol−1Å−1 with an MMFF94x force field, and the partial charges were automatically calculated. The preparation of the enzyme structure was performed for molecular docking using the Protonate 3D protocol with the default options in MOE. The London dG scoring function and Triangle Matcher placement method were used in the docking protocol. First, validation of the docking processes was established by docking the native ligands, followed by docking derivatives 7, 8 and 15 within the ATP-binding sites of EGFRWT, EGFRT790M and HER-2 after the elimination of the co-crystallized ligands.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules27206960/s1, include spectral and biological data of synthesized compound. Figure S1. Dose dependent cytotoxic activity of the synthesized derivatives against HCT-116 cancer cells according to the MTT assay. Figure S2. Dose dependent cytotoxic activity of the synthesized derivatives against MCF-7 cancer cells according to the MTT assay. Figure S3. IC50 (µM) data of the screened targets in comparison with doxorubicin against human HCT-116 and MCF7 cancer cell lines according to the MTT assay. Figure S4. Apoptotic activity of the promising derivatives 7 and 15. Figure S5. Cell cycle analysis in MCF-7 cells treated with the promising derivatives 7 and 15. Figure S6. 3D diagrams of the superimposition of the original ligands erlotinib, gefitinib and TAK-285 (red), 7 (blue), 8 (yellow) and 15 (green), within the ATP-binding pockets of EGFRWT, EGFRT790M and HER-2 (PDB codes: 1M17, 3UG2 and 3RCD), respectively. 1H-NMR and 13 C-NMR for compound 2,3,5,6,7,8,11,12,13,14.

Author Contributions

Conceptualization, F.M.A., W.A.E.-S., H.H.E. and M.N.E.-B.; methodology, M.N.E.-B., W.A.E.-S., E.S.N. and H.M.A.; software, E.S.N., W.A.E.-S., H.H.E. and F.M.A.; validation, F.M.A., W.A.E.-S. and H.H.E.; formal analysis, F.M.A., W.A.E.-S. and H.H.E.; investigation, M.N.E.-B.; W.A.E.-S., F.M.A. and E.S.N.; resources, F.M.A., W.A.E.-S. and H.H.E.; data curation, E.S.N. and W.A.E.-S.; writing—original draft preparation, H.H.E., M.N.E.-B., W.A.E.-S. and F.M.A., writing—review and editing, and W.A.E.-S., F.M.A., H.H.E. and M.N.E.-B.; visualization, F.M.A., M.N.E.-B., E.S.N., H.H.E. and W.A.E.-S.; supervision, W.A.E.-S. and F.M.A.; project administration, W.A.E.-S. and F.M.A. and H.H.E.; funding acquisition, F.M.A., W.A.E.-S. and H.H.E. All authors have read and agreed to the published version of the manuscript.

Funding

The researchers would like to thank the Deanship of Scientific Research, Qassim University for funding the publication of this project.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Avin, B.R.V.; Thirusangu, P.; Ranganatha, V.L.; Firdouse, A.; Prabhakar, B.T.; Khanum, S.A. Synthesis and tumor inhibitory activity of novel coumarin analogs targeting angiogenesis and apoptosis. Eur. J. Med. Chem. 2014, 75, 211–221. [Google Scholar] [CrossRef] [PubMed]
  2. Jiang, N.; Zhai, X.; Zhao, Y.; Liu, Y.; Qi, B.; Tao, H.; Gong, P. Synthesis and biological evaluation of novel 2-(2-arylmethylene)hydrazinyl-4-aminoquinazoline derivatives as potent antitumor agents. Eur. J. Med. Chem. 2012, 54, 534–541. [Google Scholar] [CrossRef] [PubMed]
  3. Jain, A.K.; Sharma, S.; Vaidya, A.; Ravichandran, V.; Agrawal, R.K. 1, 3, 4-thiadiazole and its derivatives: A review on recent progress in biological activities. Chem. Biol. Biol. Biol. Biol. Drug Des. 2013, 81, 557–576. [Google Scholar] [CrossRef]
  4. Kushwaha, N.; Kushwaha, S.K.S.; Rai, A.K. Biological activities of thiadiazole derivatives: A review. Int. J. Chem. Res. 2012, 4, 517–531. [Google Scholar]
  5. Gomha, S.M.; Salah, T.A.; Abdelhamid, A.O. Synthesis, characterization, and pharmacological evaluation of some novel thiadiazoles and thiazoles incorporating pyrazole moiety as anticancer agents. Monatsh. Chem. 2015, 146, 149–158. [Google Scholar] [CrossRef]
  6. Gomha, S.M.; Abdel-aziz, H.M. Synthesis and antitumor activity of 1,3,4-thiadiazole derivatives bearing coumarine ring. Heterocycles 2015, 91, 583–592. [Google Scholar] [CrossRef]
  7. Siddiqui, N.; Ahuja, P.; Ahsan, W.; Pandeya, S.N.; Alam, M.S. Thiadiazoles: Progress report on biological activities. J. Chem. Pharm. Res. 2009, 1, 19–30. [Google Scholar]
  8. Foroumadi, A.; Kargar, Z.; Sakhteman, A.; Sharifzadeh, Z.; Feyzmohammadi, R.; Kazemi, M.; Shafiee, A. Synthesis and antimycobacterial activity of some alkyl [5-(nitroaryl)-1,3,4-thiadiazol-2-ylthio]propionates. Bioorganic Med. Chem. Lett. 2006, 16, 1164–1167. [Google Scholar] [CrossRef] [PubMed]
  9. Kumar, D.; Kumar, N.M.; Chang, K.H.; Shah, K. Synthesis and anticancer activity of 5-(3-indolyl)-1,3,4-thiadiazoles. Eur. J. Med. Chem. 2010, 45, 4664–4668. [Google Scholar] [CrossRef] [PubMed]
  10. Ay, K.; Ispartaloglu, B.; Halay, E.; Ay, E.; Yasa, I.; Karayıldırım, T. Synthesis and antimicrobial evaluation of sulfanilamide- and carbohydrate-derived 1,4-disubstitued-1,2,3-triazoles via click chemistry. Med. Chem. Res. 2017, 26, 1497–1505. [Google Scholar] [CrossRef]
  11. Subhashini, N.J.P.; Kumar, E.P.; Gurrapu, N.; Yerragunta, V. Design and synthesis of imidazolo-1,2,3-triazoles hybrid compounds by microwave-assisted method: Evaluation as an antioxidant and antimicrobial agents and molecular docking studies. J. Mol. Struct. 2019, 1180, 618–628. [Google Scholar] [CrossRef]
  12. Saeedi, M.; Mohammadi-Khanaposhtani, M.; Pourrabia, P.; Razzaghi, N.; Ghadimi, R.; Imanparast, S.; Rastegar, H. Design and synthesis of novel quinazolinone-1,2,3-triazole hybrids as new anti-diabetic agents: In vitro α-glucosidase inhibition, kinetic, and docking study. Bioorg. Chem. 2019, 83, 161–169. [Google Scholar] [CrossRef]
  13. Gholampour, M.; Ranjbar, S.; Edraki, N.; Mohabbati, M.; Firuzi, O.; Khosh-neviszadeh, M. Click chemistry-assisted synthesis of novel aminonaphtho- quinone-1,2,3-triazole hybrids and investigation of their cytotoxicity and cancer cell cycle alterations. Bioorg. Chem. 2019, 88, 102967. [Google Scholar] [CrossRef] [PubMed]
  14. Chinthala, Y.; Thakur, S.; Tirunagari, S.; Chinde, S.; Domatti, A.K.; Arigari, N.K.; Tiwari, A. Synthesis, docking and ADMET studies of novel chalcone triazoles for anti-cancer and anti-diabetic activity. Eur. J. Med. Chem. 2015, 93, 564–573. [Google Scholar] [CrossRef]
  15. Rao, P.S.; Kurumurthy, C.; Veeraswamy, B.; Kumar, G.S.; Poornachandra, Y.; mar, C.G.K.; Vasamsetti, S.B.; Kotamraju, S.; Narsaiah, B. Synthesis of novel 1,2,3-triazole substituted- N -alkyl/aryl nitrone derivatives, their anti-inflammatory and anti-cancer activity. Eur. J. Med. Chem. 2014, 80, 184–191. [Google Scholar]
  16. Alminderej, F.M.; Elganzory, H.H.; El-Bayaa, M.N.; Awad, H.M.; El-Sayed, W.A. Synthesis and cytotoxic activity of new 1, 3, 4-thiadiazole thioglycosides and 1, 2, 3-triazolyl-1, 3, 4-thiadiazole N-glycosides. Molecules 2019, 24, 3738. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  17. Gür, M.; Yerlikaya, S.; Şener, N.; Özkınalı, S.; Baloglu, M.C.; Gökçe, H.; Altunoglu, Y.C.; Demir, S.; Şener, İ. Antiproliferative-antimicrobial properties and structural analysis of newly synthesized Schiff bases derived from some 1, 3, 4-thiadiazole compounds. J. Mol. Struct. 2020, 1219, 128570. [Google Scholar] [CrossRef]
  18. El-Naggar, M.; Sallam, H.A.; Shaban, S.S.; Abdel-Wahab, S.S.; EAmr, A.E.G.; Azab, M.E.; Nossier, E.S.; Al-Omar, M.A. Design, synthesis, and molecular docking study of novel heterocycles incorporating 1, 3, 4-thiadiazole moiety as potential antimicrobial and anticancer agents. Molecules 2019, 24, 1066. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  19. Khattab, R.R.; Alshamari, A.K.; Hassan, A.A.; Elganzory, H.H.; El-Sayed, W.A.; Awad, H.M.; Nossier, E.S.; Hassan, N.A. Click chemistry based synthesis, cytotoxic activity and molecular docking of novel triazole-thienopyrimidine hybrid glycosides targeting EGFR. J. Enzym. Inhib. Med. Chem. 2021, 36, 504–516. [Google Scholar] [CrossRef]
  20. Medvedev, A.; Buneeva, O.; Gnedenko, O.V.; Ershov, P.V.; Ivanov, A. Isatin, an endogenous nonpeptide biofactor: A review of its molecular targets, mechanisms of actions, and their biomedical implications. BioFactors 2018, 44, 95–108. [Google Scholar] [CrossRef]
  21. Hu, H.; Wu, J.; Ao, M.; Zhou, X.; Li, B.; Cui, Z.; Wu, T.; Wang, L.; Xue, Y.; Wu, Z.; et al. Design, synthesis and biological evaluation of methylenehydrazine-1-carboxamide derivatives with (5-((4-(pyridin-3-yl) pyrimidin-2-yl) amino)-1H-indole scaffold: Novel potential CDK9 inhibitors. Bioorg. Chem. 2020, 102, 104064. [Google Scholar] [CrossRef]
  22. Al-Warhi, T.; El Kerdawy, A.M.; Aljaeed, N.; Ismael, O.E.; Ayyad, R.R.; Eldehna, W.M.; Abdel-Aziz, H.A.; Al-Ansary, G.H. Synthesis, biological evaluation and in silico studies of certain oxindole–indole conjugates as anticancer CDK inhibitors. Molecules 2020, 25, 2031. [Google Scholar] [CrossRef] [PubMed]
  23. Mohamed, A.M.; Al-Qalawi, H.R.; El-Sayed, W.A.; Arafa, W.A.; Alhumaimess, M.S.; Hassan, A.K. Anticancer activity of newly synthesized triazolopyrimidine derivatives and their nucleoside analogs. Acta Pol. Pharm. Drug Res. 2015, 72, 307–318. [Google Scholar]
  24. Rahman, A.A.; Nassar, I.F.; Shaban, A.K.; El-Kady, D.S.; Awad, H.M.; El Sayed, W.A. Synthesis, docking studies into CDK-2 and anticancer activity of new derivatives based pyrimidine scaffold and their derived glycosides. Mini. Rev. Med. Chem. 2019, 19, 1093–1110. [Google Scholar] [CrossRef]
  25. Halay, E.; Ay, E.; Şalva, E.; Ay, K.; Karayıldırım, T. Syntheses of 1,2,3-triazolebridged pyranose sugars with purine and pyrimidine nucleobases and evaluation of their anticancer potential. Nucleosides Nucleotides Nucleic Acids 2017, 36, 598–619. [Google Scholar]
  26. Ghorab, M.M.; Alsaid, M.S.; Soliman, A.M. Dual EGFR/HER2 inhibitors and apoptosis inducers: New benzo [g] quinazoline derivatives bearing benzenesulfonamide as anticancer and radiosensitizers. Bioorg. Chem. 2018, 80, 611–620. [Google Scholar] [CrossRef] [PubMed]
  27. Das, D.; Xie, L.; Wang, J.; Xu, X.; Zhang, Z.; Shi, J.; Le, X.; Hong, J. Discovery of new quinazoline derivatives as irreversible dual EGFR/HER2 inhibitors and their anticancer activities–Part 1. Bioorganic Med. Chem. Lett. 2019, 29, 591–596. [Google Scholar] [CrossRef] [PubMed]
  28. Ahmed, S.; Sami, A.; Xiang, J. HER2-directed therapy: Current treatment options for HER2-positive breast cancer. Breast Cancer 2015, 22, 101–116. [Google Scholar] [CrossRef]
  29. Ross, J.S.; Slodkowska, E.A.; Symmans, W.F.; Pusztai, L.; Ravdin, P.M.; Hortobagyi, G.N. The HER-2 receptor and breast cancer: Ten years of targeted anti–HER-2 therapy and personalized medicine. Oncologist 2009, 14, 320–368. [Google Scholar] [CrossRef] [Green Version]
  30. Eroglu, Z.; Tagawa, T.; Somlo, G. Human epidermal growth factor receptor familytargeted therapies in the treatment of HER2-overexpressing breast cancer. Oncologist 2014, 19, 135–150. [Google Scholar] [CrossRef] [Green Version]
  31. Hsu, J.L.; Hung, M.-C. The role of HER2, EGFR, and other receptor tyrosine kinases in breast cancer. Cancer Metastasis Rev. 2016, 35, 575–588. [Google Scholar] [CrossRef] [Green Version]
  32. Elferink, L.A.; Resto, V.A. Receptor-Tyrosine-Kinase-Targeted Therapies for Head and Neck Cancer. J. Signal Transduct. 2011, 2011, 982879. [Google Scholar] [CrossRef] [Green Version]
  33. Schuler, M.; Yang, J.H.; Park, K.; Kim, J.H.; Bennouna, J.; Chen, Y.M.; Chouaid, C.; De Marinis, F.; Feng, J.F.; Grossi, F.; et al. Afatinib beyond progression in patients with non-small-cell lung cancer following chemotherapy, erlotinib/gefitinib and afatinib: Phase III randomized LUX-Lung 5 trial. Ann. Oncol. 2016, 27, 417–423. [Google Scholar] [CrossRef]
  34. El-Sharief, A.M.S.; Ammar, Y.A.; Belal, A.; El-Sharief, M.A.S.; Mohamed, Y.A.; Mehany, A.B.; Ali, G.A.E.; Ragab, A. Design, synthesis, molecular docking and biological activity evaluation of some novel indole derivatives as potent anticancer active agents and apoptosis inducers. Bioorg. Chem. 2019, 85, 399–412. [Google Scholar] [CrossRef]
  35. Nagarsenkar, A.; Prajapti, S.K.; Guggilapu, S.D.; Birineni, S.; Kotapalli, S.S.; Ummanni, R.; Babu, B.N. Investigation of triazole-linked indole and oxindole glycoconjugates as potential anticancer agents: Novel Akt/PKB signaling pathway inhibitors. Med. Chem. Comm. 2016, 7, 646–653. [Google Scholar] [CrossRef]
  36. Abbas, H.S.; el Sayed, W.A.; Fathy, N.M. Synthesis and antitumor activity of new dihydropyridine thioglycosides and their corresponding dehydrogenated forms. Eur. J. Med. Chem. 2010, 45, 973–982. [Google Scholar] [CrossRef]
  37. Nassar, I.F.; el Kady, D.S.; Awad, H.M.; El-Sayed, W.A. Design, Synthesis, and Anticancer Activity of New Oxadiazolyl-Linked and Thiazolyl-Linked Benzimidazole Arylidines, Thioglycoside, and Acyclic Analogs. J. Heterocycl. Chem. 2019, 56, 1086–1100. [Google Scholar] [CrossRef]
  38. Kassem, A.F.; Abbas, E.M.H.; El-Kady, D.S.; Awad, H.M.; El-Sayed, W.A. Design, synthesis and anticancer activity of new thiazole-tetrazole or triazole hybrid glycosides targeting CDK-2 via structure-based virtual screening. Mini Rev. Med. Chem. 2019, 19, 933–948. [Google Scholar] [CrossRef]
  39. Yousif, M.N.M.; El-Sayed, W.A.; Abbas, H.A.S.; Awad, H.M.; Yousif, N.M. Anticancer activity of new substituted pyrimidines, their thioglycosides and thiazolopyrimidine derivatives. J. Appl. Pharm. Sci. 2019, 7, 21–32. [Google Scholar]
  40. Flefel, E.E.; Tantawy, W.A.; El-Sayed, W.A.; Sayed, H.H.; Fathy, N.M. Synthesis and Anticancer Activity of New Substituted Pyrazoles and Their Derived 1,2,4-Triazoles and Their Sugar Derivatives. J. Hetererocyclic Chem. 2013, 50, 344–350. [Google Scholar] [CrossRef]
  41. Abdel-Aal, M.T.; El-Sayed, W.A.; AH, A.A.; El Ashry, E.S. Synthesis of some functionalized arylaminomethyl-1, 2, 4-triazoles, 1, 3, 4-oxa-and thiadiazoles. Die Pharmazie 2003, 58, 788–792. [Google Scholar]
  42. Srour, A.M.; El-Bayaa, M.N.; Omran, M.M.; Sharaky, M.M.; El-Sayed, W.A. Synthesis and Cytotoxic Properties of New Substituted Glycosides-Indole Conjugates as Apoptosis Inducers in Cancer Cells. Anti-Cancer Agents Med. Chem. 2021, 20, 450–463. [Google Scholar] [CrossRef] [PubMed]
  43. Hassan, A.S.; Moustafa, G.O.; Awad, H.M.; Nossier, E.S.; Mady, M.F. Design, Synthesis, Anticancer Evaluation, Enzymatic Assays, and a Molecular Modeling Study of Novel Pyrazole–Indole Hybrids. ACS Omega 2021, 6, 12361–12374. [Google Scholar] [CrossRef] [PubMed]
  44. Abd El-Meguid, E.A.; Moustafa, G.O.; Awad, H.M.; Zaki, E.R.; Nossier, E.S. Novel benzothiazole hybrids targeting EGFR: Design, synthesis, biological evaluation and molecular docking studies. J. Mol. Struct. 2021, 1240, 130595. [Google Scholar] [CrossRef]
  45. Othman, I.M.; Gad-Elkareem, M.A.; Amr, A.E.G.E.; Al-Omar, M.A.; Nossier, E.S.; Elsayed, E.A. Novel heterocyclic hybrids of pyrazole targeting dihydrofolate reductase: Design, biological evaluation and in silico studies. J. Enzym. Inhib. Med. Chem. 2020, 35, 1491–1502. [Google Scholar] [CrossRef] [PubMed]
  46. Hashem, H.E.; Amr, A.E.G.E.; Nossier, E.S.; Elsayed, E.A.; Azmy, E.M. Synthesis, antimicrobial activity and molecular docking of novel thiourea derivatives tagged with thiadiazole, imidazole and triazine moieties as potential DNA gyrase and topoisomerase IV inhibitors. Molecules 2020, 25, 2766. [Google Scholar] [CrossRef]
  47. Khattab, R.R.; Hassan, A.A.; AOsman, D.A.; Abdel-Megeid, F.M.; Awad, H.M.; Nossier, E.S.; El-Sayed, W.A. Synthesis, anticancer activity and molecular docking of new triazolo [4, 5-d] pyrimidines based thienopyrimidine system and their derived N-glycosides and thioglycosides. Nucleosides Nucleotides Nucleic Acids 2021, 40, 1090–1113. [Google Scholar] [CrossRef]
  48. Yoshikawa, S.; Kukimoto-Niino, M.; Parker, L.; Handa, N.; Terada, T.; Fujimoto, T.; Terazawa, Y.; Wakiyama, M.; Sato, M.; Sano, S.; et al. Structural basis for the altered drug sensitivities of non-small cell lung cancer-associated mutants of human epidermal growth factor receptor. Oncogene 2013, 32, 27–38. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  49. Ishikawa, T.; Seto, M.; Banno, H.; Kawakita, Y.; Oorui, M.; Taniguchi, T.; Ohta, Y.; Tamura, T.; Nakayama, A.; Miki, H.; et al. Design and synthesis of novel human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR) dual inhibitors bearing a pyrrolo [3, 2-d] pyrimidine scaffold. J. Med. Chem. 2011, 54, 8030–8050. [Google Scholar] [CrossRef]
  50. Abuelizz, H.A.; Marzouk, M.; Bakheit, A.H.; Awad, H.M.; Soltan, M.M.; Naglah, A.M.; Al-Salahi, R. Antiproliferative and Antiangiogenic Properties of New VEGFR-2-targeting 2-thioxobenzo [g] quinazoline Derivatives (In Vitro). Molecules 2020, 25, 5944. [Google Scholar] [CrossRef] [PubMed]
  51. Nossier, E.S.; El-Hallouty, S.M.; Zaki, E.R. Synthesis, anticancer evaluation and molecular modeling of some substituted thiazolidinonyl and thiazolyl pyrazole derivatives. Int. J. Pharm. Sci. 2015, 7, 353–359. [Google Scholar]
  52. Dawood, D.H.; Nossier, E.S.; Ali, M.M.; Mahmoud, A.E. Synthesis and molecular docking study of new pyrazole derivatives as potent anti-breast cancer agents targeting VEGFR-2 kinase. Bioorg. Chem. 2020, 101, 103916. [Google Scholar] [CrossRef]
  53. Othman, I.M.; Alamshany, Z.M.; Tashkandi, N.Y.; Gad-Elkareem, M.A.; Anwar, M.M.; Nossier, E.S. New pyrimidine and pyrazole-based compounds as potential EGFR inhibitors: Synthesis, anticancer, antimicrobial evaluation and computational studies. Bioorg. Chem. 2021, 114, 105078. [Google Scholar] [CrossRef] [PubMed]
Molecules 27 06960 g001 550
Figure 1. Reported anticancer agents bearing 1,3,4-thiadiazol, 1,2,3-triazole, indole and glycoside fragments.
Figure 1. Reported anticancer agents bearing 1,3,4-thiadiazol, 1,2,3-triazole, indole and glycoside fragments.
Molecules 27 06960 g001
Molecules 27 06960 g002 550
Figure 2. Reported EGFR inhibitors and the design concept of glycosides linked to indole–thiadiazole–triazole bases or substituted arylacetamino–triazole hybrids.
Figure 2. Reported EGFR inhibitors and the design concept of glycosides linked to indole–thiadiazole–triazole bases or substituted arylacetamino–triazole hybrids.
Molecules 27 06960 g002
Molecules 27 06960 sch001 550
Scheme 1. Synthesis of indolyl-thiadiazolyl-1,2,3-triazolyl hybrid glycosides.
Scheme 1. Synthesis of indolyl-thiadiazolyl-1,2,3-triazolyl hybrid glycosides.
Molecules 27 06960 sch001
Molecules 27 06960 sch002 550
Scheme 2. Synthesis of arylaminoacetamide triazolyl glycosides.
Scheme 2. Synthesis of arylaminoacetamide triazolyl glycosides.
Molecules 27 06960 sch002
Molecules 27 06960 g003 550
Figure 3. Analysis of the cell cycle and the effect of derivatives 7 and 15 on the percentage of annexin V-FITC-positive staining in MCF-7 cells in comparison with the control.
Figure 3. Analysis of the cell cycle and the effect of derivatives 7 and 15 on the percentage of annexin V-FITC-positive staining in MCF-7 cells in comparison with the control.
Molecules 27 06960 g003
Molecules 27 06960 g004a 550Molecules 27 06960 g004b 550
Figure 4. (A–C) Two-dimensional views of compounds 7, 8 and 15, respectively, docked in the active binding site of EGFRWT (PDB ID: 1M17) using MOE software.
Figure 4. (A–C) Two-dimensional views of compounds 7, 8 and 15, respectively, docked in the active binding site of EGFRWT (PDB ID: 1M17) using MOE software.
Molecules 27 06960 g004aMolecules 27 06960 g004b
Molecules 27 06960 g005a 550Molecules 27 06960 g005b 550Molecules 27 06960 g005c 550
Figure 5. (A–C) Two-dimensional views of compounds 7, 8 and 15, respectively, docked in the active binding site of EGFRT790M (PDB ID: 3UG2) using MOE software.
Figure 5. (A–C) Two-dimensional views of compounds 7, 8 and 15, respectively, docked in the active binding site of EGFRT790M (PDB ID: 3UG2) using MOE software.
Molecules 27 06960 g005aMolecules 27 06960 g005bMolecules 27 06960 g005c
Molecules 27 06960 g006a 550Molecules 27 06960 g006b 550
Figure 6. (A–C) Two-dimensional views of compounds 7, 8 and 15, respectively, docked in the active binding site of HER-2 (PDB ID: 3RCD) using MOE software.
Figure 6. (A–C) Two-dimensional views of compounds 7, 8 and 15, respectively, docked in the active binding site of HER-2 (PDB ID: 3RCD) using MOE software.
Molecules 27 06960 g006aMolecules 27 06960 g006b
Table
Table 1. IC50 of the synthesized compounds against the two cancer cell lines according to the MTT assay.
Table 1. IC50 of the synthesized compounds against the two cancer cell lines according to the MTT assay.
Compound No.IC50 (µM) ± SD
HCT-116MCF-7
146.9 ± 0.518.1 ± 0.2
252.7 ± 0.614.1 ± 0.3
330.8 ± 0.41.1 ± 0.1
522.6 ± 0.213.9 ± 0.2
620.8 ± 0.210.8 ± 1.5
715.5 ± 0.20.5 ± 0.0
84.6 ± 0.14.2 ± 0.1
9a42.3 ± 0.624.1 ± 0.3
9b33.3 ± 0.426.4 ± 0.3
1115.4 ± 0.20.8 ± 0.0
122.2 ± 0.15.7 ± 0.1
1338.2 ± 0.534.4 ± 0.4
1433.8 ± 0.335.3 ± 0.3
1511.4 ± 0.30.6 ±0.0
1635.7 ± 0.420.3 ± 0.9
1726.5 ± 0.330.1 ± 0.4
1828.8 ± 0.131.6 ± 0.5
Doxorubicin12.1 ± 0.29.4 ± 0.1
IC50: The compound concentration that inhibits the proliferation of cells by 50%; SD: mean of the standard deviation; each value is the mean of three values.
Table
Table 2. Kinase inhibition assessment of the highly potent derivatives 7, 8, 11, 12 and 15 (IC50 in μM) against EGFRWT, EGFRT790M and HER-2 enzymes.
Table 2. Kinase inhibition assessment of the highly potent derivatives 7, 8, 11, 12 and 15 (IC50 in μM) against EGFRWT, EGFRT790M and HER-2 enzymes.
CompoundsIC50 (Mean ± SEM) (µM)
EGFRWTEGFRT790MHER-2
70.30 ± 0.011.12 ± 0.552.25 ± 0.30
80.38 ± 0.051.95 ± 0.022.77 ± 0.13
116.45 ± 0.1011.80 ± 0.058.60 ± 0.20
1212.70 ± 0.1515.22 ± 0.2018. 40 ± 0.12
150.21 ± 0.051.50 ± 0.112.18 ± 0.42
Erlotinib0.13 ± 0.010.62 ± 0.101.40 ± 0.05
IC50: The compound concentration required to inhibit the enzyme viability by 50%; SEM = standard error mean; each value is the mean of three values.
Table
Table 3. Apoptosis and necrosis data on MCF-7 cells induced by the most potent derivatives 7 and 15.
Table 3. Apoptosis and necrosis data on MCF-7 cells induced by the most potent derivatives 7 and 15.
Compd.ApoptosisNecrosis
TotalEarlyLate
7/MCF-734.614.3918.8111.41
15/MCF-742.452.6925.4814.28
Cont./MCF-71.990.460.281.25
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Share and Cite

MDPI and ACS Style

Elganzory, H.H.; Alminderej, F.M.; El-Bayaa, M.N.; Awad, H.M.; Nossier, E.S.; El-Sayed, W.A. Design, Synthesis, Anticancer Activity and Molecular Docking of New 1,2,3-Triazole-Based Glycosides Bearing 1,3,4-Thiadiazolyl, Indolyl and Arylacetamide Scaffolds. Molecules 2022, 27, 6960. https://doi.org/10.3390/molecules27206960

AMA Style

Elganzory HH, Alminderej FM, El-Bayaa MN, Awad HM, Nossier ES, El-Sayed WA. Design, Synthesis, Anticancer Activity and Molecular Docking of New 1,2,3-Triazole-Based Glycosides Bearing 1,3,4-Thiadiazolyl, Indolyl and Arylacetamide Scaffolds. Molecules. 2022; 27(20):6960. https://doi.org/10.3390/molecules27206960

Chicago/Turabian Style

Elganzory, Hussein H., Fahad M. Alminderej, Mohamed N. El-Bayaa, Hanem M. Awad, Eman S. Nossier, and Wael A. El-Sayed. 2022. "Design, Synthesis, Anticancer Activity and Molecular Docking of New 1,2,3-Triazole-Based Glycosides Bearing 1,3,4-Thiadiazolyl, Indolyl and Arylacetamide Scaffolds" Molecules 27, no. 20: 6960. https://doi.org/10.3390/molecules27206960

Article Metrics

Back to TopTop