Synthesis, in silico ADME, molecular docking and in vitro cytotoxicity evaluation of stilbene linked 1,2,3-triazoles.

Series of (E)-1-benzyl-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazoles 7a-x were obtained by Wittig reaction between 4-((1-benzyl-1H-1,2,3-triazol-4-yl)methoxy)benzaldehydes 5a-d and benzyl triphenylphosphonium halides 6a-f in benzene. The structures of the synthesized compounds were confirmed by FTIR, NMR (1H and 13C NMR) spectroscopy, and mass spectrometry. All synthesized compounds were screened for their cytotoxic activity against human cancer cell lines including pancreatic carcinoma, colorectal carcinoma, lung carcinoma, and leukemias such as acute lymphoblastic, chronic myeloid, and non-Hodgkinson lymphoma cell lines. In vitro cytotoxicity data showed that compounds 7c, 7e, 7h, 7j, 7k, 7r, and 7w were moderately cytotoxic (11.6-19.3 μM) against the selected cancer cell lines. These cytotoxicity findings were supported using molecular docking studies of the compounds against 1TUB receptor. The drug-likeness properties of the compounds evaluated by in silico ADME analyses. Resveratrol linked 1,2,3-triazoles were more sensitive towards human carcinoma cell lines but least sensitive towards leukemia and lymphoma cell lines.

Introduction

pan class="Disease">Cancer is a group of diseases responsible for one in six deaths worldwide. To overcome this threat, effective methods such as immunotherapy, chemotherapy, surgery, and radiotherapy are needed. Each method has its advantages and disadvantages. Chemotherapeutic agents used to kill or inhibit the growth of cancer cells often have serious side effects, whereas radiotherapy and surgery are limited [1]. To fill this void, there is always a need for better alternatives. It is a daunting task to develop a new anticancer compound with improved pharmaceutical properties. The role of heterocyclic chemistry is commendable in this regard. Low toxicity, high regeneration, and better receptor binding make nitrogen (N) -containing heterocycle the first choice between synthons in the drug discovery process [2].

Three pan class="Chemical">nitrogens and two carbon atoms of triazole contain a five heterocyclic compound ring, a 1,2,3-triazole ring exhibits a variety of biological functions, including antiviral, anti-inflammatory, antimicrobial and anti-tubercular. In addition, 1,4-disubstituted 1,2,3-triazoles show significant anticancer activity [3, 4, 5]. Recently Kaushik et al, developed and synthesized amide linked 1,4-disubstituted 1,2,3-triazoles (I) as an anticancer agents [6]. Murugavel et al, have been linked to the production of thiophen containing 1,2,3-triazole (II) and pyridine moiety as a potential for topoisomerase IIα inhibiting anticancer agents [7]. A series of connected chalcone 1,2,3 triazoles (III) was synthesized using a green chemical method and tested as anticancer agents [8].

pan class="Chemical">Stilbene based compounds have attracted biologists and chemists because they are widely available in nature. They have a variety of biological functions [9, 10]. Hydroxylated stilbenes have been found in medicinal plants but plain stilbene is not found in nature. Trans-3,5,4′-trihydroxy stilbene (resveratrol) (IV) is found in grapes and plays a role in preventing coronary heart disease associated with the use of red wine [11, 12, 13]. This resveratrol exhibits the activity of many biological agents, such as chemopreventive [14] antioxidant [15] antineoplastic [16] and antiestrogenic [17]. Various extracts/structures of stilbenes show anticancer activity [18, 19, 20, 21].

In recent times, the molepan class="Chemical">cular hybridization approach is a widely used techniques in drug discovery, which forms new molecular entities by incorporating stilbenes by linker through the methylene with 1,2,3-triazoles. These integrated or cohesive systems may have advanced biological properties related to specific substances. As the continuation of our work in small nitrogenous heterocyclic compounds, a series of E stilbene linked to 1,4-disubstituted-1,2,3-triazole derivatives (7a-x) were synthesized, identified, and in vitro cytotoxicity is performed in this paper (see Figure 1).

Figure 1

Pharmacologically hybridized/linked 1,2,3-triazole derivatives such as amide linked 1,4-disubstituted 1,2,3-triazoles I, thiophen containing 1,2,3-triazole pyridine II, chalcone linked 1,2,3-triazole III, resveratrol IV and resveratrol linked 1,2,3-triazoles 7a-x.

Pharmacologically hybridized/linked pan class="Chemical">1,2,3-triazole derivatives such as amide linked 1,4-disubstituted 1,2,3-triazoles I, thiophen containing 1,2,3-triazole pyridine II, chalcone linked 1,2,3-triazole III, resveratrol IV and resveratrol linked 1,2,3-triazoles 7a-x.

Furthermore, in pan class="Chemical">silico ADME properties were investigated to determine the drug-likeness properties of the synthesized compounds using the SwissADME webserver [22, 23]. We also conducted docking simulations both to support the in vitro cytotoxicity studies of the compounds and to identify their binding sites on the 1TUB receptor (tubulin-docetaxel complex) [24].

Experimental

General information and instrumentation

Reagents and solvents were tested for purity before use. Melting points (m.p.) were measured by open capillary pan class="Gene">tube method in liquid paraffin (heavy) and are uncorrected. FTIR spectra were recorded using infrared (IR) grade potassium bromide (KBr) by diffuse reflectance technique on a JASCO 460 + instrument. The 1H NMR spectra were recorded in deuterated dimethyl sulfoxide (DMSO-d6) and chloroform (CDCl3) in the range of 400–500 MHz (MHz) on Bruker (Ultraspec AMX 400) and JEOL RESONANCE instruments. Chemical shift (δ) values in ppm were expressed using tetramethylsilane (TMS) as the reference. Compound purity was determined by an Agilent 1100 HPLC coupled to an Agilent mass spectrometry detector (MSD) with electrospray ionization in positive mode. 4-(Prop-2-ynyloxy)benzaldehyde (3) and aryl azides (4a-d) were prepared as per literature [25] and 4-((1-arylmethyl-1H-1,2,3-triazol-4-yl)methoxy)benzaldehydes (5a-d) were synthesized as per the literature [26]. Various aryltriphenylphosphonium chlorides (6a-f) were prepared as per the literature [27].

Synthesis

General procedure for synthesis of pan class="Gene">(E)-1-benzyl-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazoles (7a-x)

pan class="Chemical">Sodium hydride (0.0478 g, 2 mmol) was added in part to an equi-molar mixture of different benzyltriphenylphosphonium halides (6a-f) and 4-((1-benzyl-1H-1,2,3-triazol-4-yl)methoxy) benzaldehydes (5a-d) at 0–5 °C in dry benzene. The resulting mixture was stirred for 16 h at room temperature. Excess sodium hydride was quenched in anhydrous methanol (10 mL) followed by extraction with a chloroform-water mixture. The organic layer was dried over anhydrous Na2SO4 and removed under vacuum. The crude mass thus obtained was purified from hot ethanol to get the isomeric forms of 7a-x while remained in the solution.

pan class="Gene">(E)-1-benzyl-4-((4-styrylphenoxy) methyl)-1H-1,2,3-triazole (7a). White amorphous mass, IR (KBr) ν: = 3010, 2873, 1602, 1510, 1455, 1243 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 5.15 (2H, s, –CH2-), 5.61 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.11 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.17–7.25 (2H, md, J = 16.4 Hz, styryl –C=CH-), 7.30–7.39 (7H, m, Ar–H), 7.54 (4H, m, Ar–H), 8.27 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 52.82, 61.12, 114.97, 124.66, 126.16, 126.30, 127.06, 127.19, 127.75, 127.93, 128.13, 128.63, 128.74, 157.72. +MS (ESI) m/z: 369.1 (368.4).

pan class="Gene">(E)-1-benzyl-4-((4-(4-fluorostyryl)-phenoxy)methyl)-1H-1,2,3-triazole (7b). White amorphous mass, IR (KBr) ν: = 3074, 2790, 1605, 1514, 1455, 1266 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 5.15 (2H, s, –CH2-), 5.60 (2H, s, –OCH2-), 7.04 (2H, d, J = 11.6 Hz, Ar–H), 7.12 (2H, d, J = 6.8 Hz, Ar–H), 7.16–7.20 (2H, m, Ar–H), 7.30–7.39 (5H, m, Ar–H), 7.53 (2H, d, J = 11.2 Hz, Ar–H), 7.58–7.61 (2H, m, Ar–H), 8.27 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 52.84, 61.11, 114.97, 115.43, 115.60, 124.72, 125.15, 127.73, 127.91, 127.96, 128.01, 128.17, 128.78, 129.95, 133.97, 136.02, 142.94, 157.73, 160.43, 162.37. +MS (ESI) m/z: 386.1 (386.4).

pan class="Gene">(E)-1-benzyl-4-((4-(4-chlorostyryl)phenoxy)methyl)-1H-1,2,3-triazole (7c). White crystals, IR (KBr) ν: = 3033, 2918, 1603, 1509, 1467, 1249 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 5.15 (2H, s, –CH2-), 5.60 (2H, s, –OCH2-), 7.03 (2H, d, J = 8.4 Hz, Ar–H), 7.11 (1H, d, J = 16.8 Hz, styryl –CH=C-), 7.23 (1H, d, J = 16.8 Hz, styryl –C=CH-), 7.29–7.38 (3H, m, Ar–H), 7.45 (2H, d, J = 8.8 Hz, Ar–H), 7.55 (2H, d, J = 8.8 Hz, Ar–H), 7.54 (2H, d, J = 8.8 Hz, Ar–H), 8.27 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 53.37, 61.66, 115.53, 125.25, 125.51, 128.35, 128.44, 128.49, 128.70, 129.17, 129.31, 129.42, 130.30, 131.94, 136.55, 136.90, 139.73, 143.44, 158.43. +MS (ESI) m/z: 402.1 (402.9).

pan class="Gene">(E)-1-benzyl-4-((4-(4-methylstyryl)phenoxy)methyl)-1H-1,2,3-triazole (7d). White crystals, IR (KBr) ν: = 3070, 2964, 1603, 1514, 1476, 1244 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 2.29 (3H, s, –CH3), 5.14 (2H, s, –CH2-), 5.60 (2H, s, 2H, –OCH2-), 7.03 (2H, d, J = 8.8 Hz, Ar–H), 7.06 (1H, d, J = 16.8 Hz, styryl –CH=C-), 7.10 (1H, d, J = 16.8 Hz, styryl –C=CH-), 7.17 (2H, d, J = 8 Hz, Ar–H), 7.29–7.39 (4H, m, Ar–H), 7.45 (2H, d, J = 8 Hz, Ar–H), 7.52 (2H, d, J = 8.8 Hz, Ar–H), 8.27 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): = δ 20.78, 52.81, 61.10, 124.65, 126.08, 126.23, 126.39, 127.57, 127.92, 128.12, 128.73, 129.23, 130.13, 134.53, 135.98, 136.50, 143.05, 157.59, 178.69. +MS (ESI) m/z: 382.1 (382.5).

pan class="Gene">(E)-1-benzyl-4-((4-(4-methoxystyryl)phenoxy)methyl)-1H-1,2,3-triazole (7e). White amorphous mass, IR (KBr) ν: = 3034, 2837, 1606, 1514, 1467, 1384, 1253 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 3.76 (3H, s, –OCH3), 5.14 (2H, s, –CH2-), 5.60 (2H, s, –OCH2-), 6.93 (2H, d, J = 8.8 Hz, Ar–H), 6.99–7.03 (4H, m, Ar–H), 7.30–7.39 (5H, m, Ar–H), 7.49 (4H, d, J = 8 Hz, Ar–H), 8.27 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 52.82, 55.11, 61.11, 114.11, 114.93, 124.65, 125.69, 125.95, 127.37, 127.42, 127.93, 128.13, 128.74, 129.97, 130.36, 135.99, 142.96, 157.38, 158.65. +MS (ESI) m/z: 398.1 (398.5).

pan class="Gene">(E)-1-benzyl-4-((4-(4-nitrostyryl) phenoxy)methyl)-1H-1,2,3-triazole (7f). Yellow crystals, IR (KBr) ν: = 3101, 2838, 1591, 1513, 1178 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 5.18 (2H, s, –CH2-), 5.61 (2H, s, –OCH2-), 7.09 (2H, d, J = 8.8 Hz, Ar–H), 7.29 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.30–7.39 (5H, m, Ar–H), 7.50 (1H, d, J = 16.4 Hz, styryl –C=CH-), 7.63 (2H, d, J = 8.8 Hz, Ar–H), 7.82 (2H, d, J = 8.8 Hz, Ar–H), 8.22 (2H, d, J = 8.8 Hz, Ar–H), 8.28 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 53.40, 61.70, 115.65, 124.61, 124.75, 125.32, 127.47, 128.52, 128.73, 129.18, 129.33, 129.81, 133.52, 136.56, 143.37, 145.04, 146.37, 159.13. +MS (ESI) m/z: 413.1 (413.4).

pan class="Gene">(E)-1-(4-nitrobenzyl)-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazole (7g). Yellow amorphous powder, IR (KBr) ν: = 3087, 2872, 1606, 1515, 1447, 1219 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 5.18 (2H, s, –CH2-), 5.80 (2H, s,–OCH2–), 7.05 (2H, d, J = 8.8 Hz, Ar–H), 7.11 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.21 (1H, d, J = 16.8 Hz, styryl –C=CH-), 7.25 (1H, d, J = 7.2 Hz, Ar–H), 7.35 (2H, t, J = 15.6 Hz, Ar–H), 7.51–7.56 (5H, m, Ar–H), 8.25 (2H, d, J = 8.0 Hz, Ar–H), 8.38 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 51.92, 61.10, 114.99, 123.95, 125.16, 126.19, 126.34, 127.23, 127.79, 127.95, 128.67, 129.05, 130.05, 137.33, 143.12, 143.42, 147.25, 157.69. +MS (ESI) m/z: 414.1 (413.4).

pan class="Gene">(E)-4-((4-(4-fluorostyryl)phenoxy)methyl)-1-(4-nitrobenzyl)-1H-1,2,3-triazole (7h). Light yellow crystals, IR (KBr) ν: = 3098, 2874, 1607, 1517, 1458, 1217 cm-1. 1H NMR (400 MHz, DMSO-d6): δ 5.18 (2H, s, –CH2-), 5.80 (2H, s, –OCH2-), 7.05 (d, 2H, J = 9.2, Hz Ar–H), 7.12 (2H, d, J = 6.4 Hz, Ar–H), 7.16–7.20 (2H, m, Ar–H), 7.51–7.54 (4H, m, Ar–H), 7.57–7.61 (2H, m, Ar–H), 8.24 (2H, d, J = 8.8 Hz, Ar–H), 8.35 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 51.92, 61.11, 115.00, 115.19, 115.39, 115.56, 123.90, 125.10, 125.17, 127.71, 127.87, 127.92, 127.99, 129.01, 129.98, 131.75, 133.91, 143.12, 143.36, 147.24, 157.67, 160.41, 162.35. +MS (ESI) m/z: 431.1 (431.4).

pan class="Gene">(E)-4-((4-(4-chlorostyryl)phenoxy)methyl)-1-(4-nitrobenzyl)-1H-1,2,3-triazole (7i). Yellow amorphous mass, IR (KBr) ν: = 3084, 2781, 1604, 1514, 1457, 1348, 1256 cm-1. 1H NMR (400 MHz, DMSO-d6): δ = 5.18 (2H, s, –CH2-), 5.80 (2H, s, –OCH2-), 7.05 (2H, d, J = 8.8 Hz, Ar–H), 7.11 (1H, d, J = 16.8 Hz, styryl –CH=C-), 7.24 (1H, d, J = 16.8 Hz, styryl –C=CH-), 7.41 (2H, d, J = 8.8 Hz, Ar–H), 7.51–7.55 (4H, m, Ar–H), 7.58 (2H, d, J = 8.4 Hz, Ar–H), 8.24 (2H, d, J = 8.8 Hz, Ar–H), 8.35 (1H, s, Triazole-H).13C NMR (400 MHz, DMSO-d6): δ = 51.94, 61.11, 115.04, 123.96, 125.01, 125.18, 127.83, 127.94, 128.65, 128.87, 129.06, 129.82, 131.44, 136.37, 143.11, 143.42. +MS (ESI) m/z: 448.0 (447.9).

pan class="Gene">(E)-4-((4-(4-methylstyryl)phenoxy)methyl)-1-(4-nitrobenzyl)-1H-1,2,3-triazole (7j). Yellow crystals, IR (KBr) ν: = 3087, 2912, 1604, 1515, 1453, 1349, 1255 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.29 (3H, s, –CH3), 5.17 (2H, s, –CH2-), 5.80 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.06 (1H, s, J = 16 Hz, styryl –CH=C-), 7.10 (1H, s, J = 16 Hz, styryl –C=CH-), 7.17 (2H, d, J = 8.0 Hz, Ar–H), 7.45 (2H, d, J = 8.0 Hz, Ar–H), 7.50–7.54 (4H, dd, Ar–H), 8.24 (2H, d, J = 8.8 Hz, Ar–H), 8.35 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 20.80, 51.91, 61.08, 114.97, 123.92, 125.13, 126.27, 126.92, 127.61, 129.03, 129.25, 130.19, 134.53, 136.53, 143.13, 143.39, 147.24, 157.52. +MS (ESI) m/z: 427.1 (427.5).

pan class="Gene">(E)-4-((4-(4-methoxystyryl)phenoxy)methyl)-1-(4-nitrobenzyl)-1H-1,2,3-triazole (7k). Yellow amorphous mass, IR (KBr) ν: = 3087, 2836, 1607, 1516, 1462, 1349, 1254 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 3.76 (3H, s, –OCH3), 5.17 (2H, s, –CH2-), 5.79 (2H, s, –OCH2-), 6.93 (2H, d, J = 8 Hz, Ar–H), 7.00–7.03 (4H, m, Ar–H), 7.49 (4H, d, J = . 8.4 Hz, Ar–H), 7.53 (2H, d, J = 9 Hz, Ar–H), 8.24 (2H, d, J = 8.8 Hz, Ar–H), 8.34 (1H, s, Triazole-H).13C NMR (400 MHz, DMSO-d6): δ = 51.91, 55.11, 61.08, 114.11, 114.96, 123.92, 125.11, 125.07, 126.02, 127.43, 129.03, 129.96, 130.41, 143,15, 143.39, 147.24, 157.34, 158.65. +MS (ESI) m/z: 444.1 (443.5).

pan class="Gene">(E)-1-(4-nitrobenzyl)-4-((4-(4-nitrostyryl)phenoxy)methyl)-1H-1,2,3-triazole (7l). Yellow amorphous mass, IR (KBr) ν: = 3050, 2936, 1588, 1507, 1176 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 5.20 (2H, s, –CH2-), 5.80 (2H, s, –OCH2-), 7.09 (2H, d, J = 8.8 Hz, Ar–H), 7.29 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.50 (1H, d, J = 16.4 Hz, styryl –C=CH-), 7.54 (2H, d, J = 8.4 Hz, Ar–H), 7.63 (2H, d, J = 8.8 Hz, Ar–H), 7.82 (2H, d, J = 8.8 Hz, Ar–H), 8.22 (2H, d, J = 9.2 Hz, Ar–H), 8.25 (2H, d, J = 8.8 Hz, Ar–H), 8.36 (1H, s, Triazole-H).13C NMR (400 MHz, DMSO-d6): δ = 51.93, 61.14, 115.13, 123.92, 124.03, 124.23, 125.16, 126.90, 128.62, 129.04, 129.29, 132.93, 143.00, 143.37, 144.46, 145.82, 158.52. +MS (ESI) m/z: 458.0 (458.4).

pan class="Gene">(E)-1-(4-methylbenzyl)-4-((4-styrylphenoxy) methyl)-1H-1,2,3-triazole (7m). White crystals, IR (KBr) ν: = 3027, 2872, 1602, 1509, 1462, 1380, 1243 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.27 (3H, s, –CH3), 5.14 (2H, s, –CH2-), 5.54 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.07 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.16–7.25 (6H, m, Ar–H), 7.35 (2H, t, J = 16.0 Hz, Ar–H), 7.55 (4H, t, J = 16.8 Hz, Ar–H), 8.23 (1H, s, Triazole-H).13C NMR (400 MHz, DMSO-d6): δ 20.67, 52.63, 61.11, 114.96, 124.54, 126.16, 126.29, 127.20, 127.76, 127.99, 128.65, 129.28, 129.98, 132.99, 137.33, 137.49, 142.88, 157.72. +MS (ESI) m/z: 382.0 (382.5).

pan class="Gene">(E)-4-((4-(4-fluorostyryl)phenoxy)methyl)-1-(4-methylbenzyl)-1H-1,2,3-triazole (7n). White amorphous powder, IR (KBr) ν: = 3077, 2872, 1605, 1514, 1454, 1213 cm-1. NMR (400 MHz, DMSO-d6): δ = 2.27 (3H, s, –OCH3), 5.14 (2H, s, –CH2-), 5.54 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.12 (2H, d, J = 6.8 Hz, Ar–H), 7.16–7.22 (6H, m, Ar–H), 7.52 (2H, d, J = 8.4 Hz, Ar–H), 7.57–7.61 (2H, m, Ar–H), 8.23 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ 20.63, 52.60, 61.10, 114.95, 115.34, 115.55, 124.47, 125.11, 127.67, 127.88, 127.95, 129.24, 129.91, 132.95, 133.93, 137.45, 142.85, 157.68. +MS (ESI) m/z: 400.1 (400.5).

pan class="Gene">(E)-4-((4-(4-chlorostyryl)phenoxy) methyl)-1-(4-methylbenzyl)-1H-1,2,3-triazole (7o). White amorphous mass, IR (KBr) ν: = 3077, 2877, 1605, 1510, 1457, 1177 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.27 (3H, s, –CH3), 5.14 (2H, s, –CH2-), 5.54 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.11 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.16–7.23 (5H, m, Ar–H), 7.40 (2H, d, J = 8.8 Hz, Ar–H), 7.54 (2H, d, J = 8.8 Hz, Ar–H), 7.59 (2H, d, J = 8.8 Hz, Ar–H), 8.23 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 20.67, 52.62, 61.09, 114.95, 115.41, 115.58, 124.54, 125.13, 127.70, 127.93, 127.99, 129.28, 129.92, 132.99, 133.93, 137.50, 142.87, 157.70, 160.41, 162.32. +MS (ESI) m/z: 416.1 (416.9).

pan class="Gene">(E)-1-(4-methylbenzyl)-4-((4-(4-methylstyryl)phenoxy)methyl)-1H-1,2,3-triazole (7p). White crystals, IR (KBr) ν: = 3023, 2734, 1602, 1515, 1455, 1388, 1240 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.27 (3H, s, –CH3), 2.29 (3H, s, –CH3-), 5.13 (2H, s, –CH2-), 5.40 (2H, s,–OCH2–), 7.02 (2H, d, J = 8.8 Hz, Ar–H), 7.06 (1H, s, J = 16.8 Hz, styryl –CH=C-), 7.10 (1H, s, J = 16.8 Hz, styryl –C=CH-), 7.15–7.22 (6H, m, Ar–H), 7.45 (2H, d, J = 8.0 Hz, Ar–H), 7.51 (2H, d, J = 8.8 Hz, Ar–H), 8.23 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ 20.65, 20.78, 52.61, 61.1.0, 113.70, 114.94, 124.49, 126.08, 126.22, 126.93, 127.57, 127.97, 129.22, 129.26, 130.25, 133.01, 134.50, 136.49, 137.59, 142.89, 157.55. +MS (ESI) m/z: 396.1 (396.5).

pan class="Gene">(E)-4-((4-(4-methoxystyryl)phenoxy)methyl)-1-(4-methylbenzyl)-1H-1,2,3-triazole (7q). White amorphous mass, IR (KBr) ν: = 3079, 2840, 1605, 1515, 1395, 1249 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.27 (3H, s, –CH3), 3.76 (3H, s, 3H, –OCH3), 5.13 (2H, s, –CH2-), 5.54 (2H, s, –OCH2-), 6.93 (2H, d, J = 8.8 Hz, Ar–H), 6.99–7.02 (4H, m, Ar–H), 7.16–7.22 (4H, m, Ar–H), 7.47–7.50 (4H, m, Ar–H), 8.23 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 20.66, 52.62, 55.11, 61.10, 114.11, 114.93, 124.49, 125.69, 125.98, 127.37, 127.41, 127.97, 129.27, 129.97, 130.35, 132.99, 137.48, 142.92, 157.37, 158.64. +MS (ESI) m/z: 412.1 (412.5).

pan class="Gene">(E)-1-(4-methylbenzyl)-4-((4-(4-nitrostyryl)phenoxy)methyl)-1H-1,2,3-triazole (7r). White crystals, IR (KBr) ν: = 3075, 2926, 1592, 1509, 1465, 1388, 1219 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.27 (3H, s, –CH3), 5.17 (2H, s, –CH2-), 5.54 (2H, s, –OCH2-), 7.08 (2H, d, J = 8.4 Hz, Ar–H), 7.18 (2H, d, J = 8 Hz, Ar–H), 7.22 (2H, d, J = 8 Hz, Ar–H), 7.29 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.50 (1H, d, J = 16.4 styryl –C=CH-), 7.63 (2H, d, J = 8.8 Hz, Ar–H), 7.82 (2H, d, J = 9.2 Hz, Ar–H), 8.22 (2H, d, J = 8.8 Hz, Ar–H), 8.24 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 20.67, 52.64, 61.13, 115.09, 124.03, 124.18, 124.58, 126.89, 127.99, 128.61, 129.29, 132.96, 137.51, 142.76, 144.47, 145.81, 158.56. +MS (ESI) m/z: 427.1 (427.5).

pan class="Gene">(E)-1-(4-chlorobenzyl)-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazole (7s). White crystals, IR (KBr) ν: = 3023, 2791, 1606, 1516, 1459, 1258 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 5.15 (2H, s, –CH2-), 5.61 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.11 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.21 (1H, d, J = 16.4 Hz, styryl –C=CH-), 7.25 (1H, d, J = 7.2 Hz, Ar–H), 7.32–7.37 (4H, m, Ar–H), 7.45 (2H, d, J = 8.4 Hz, Ar–H), 7.56 (4H, t, J = 15.2 Hz, Ar–H), 8.28 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 51.01, 61.11, 114.97, 115.19, 124.73, 126.16, 126.31, 127.19, 127.76, 127.95, 128.63, 128.75, 129.89, 130.01, 131.75, 132.87, 134.98, 137.32, 142.99, 157.70, 191.38. +MS (ESI) m/z: 402.1 (402.9).

pan class="Gene">(E)-1-(4-chlorobenzyl)-4-((4-(4-fluorostyryl)phenoxy)methyl)-1H-1,2,3-triazole (7t). White crystals, IR (KBr) ν: = 3064, 2790, 1607, 1515, 1459, 1216 cm−1. 1H NMR (400 MHz, DMSO-d6): δ 5.15 = (3H, s, –CH2), 5.61 (2H, s, –OCH2-), 7.04 (2H, d, J = 8.8 Hz, Ar–H), 7.12 (2H, d, J = 6.4 Hz, Ar–H), 7.16–7.20 (2H, m, Ar–H), 7.34 (2H, d, J = 10.8 Hz, Ar–H), 7.45 (2H, d, J = 8.4 Hz, Ar–H), 7.53 (2H, d, J = 11.6 Hz, Ar–H), 7.58–7.61 (2H, m, Ar–H), 8.28 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): = δ 52.0, 61.10, 114.97, 115.40, 115.57, 124.73, 125.15, 127.70, 127.88, 127.92, 127.99, 128.75, 129.89, 129.95, 132.86, 133.92, 134.98, 142.98, 157.69, 160.41, 162.34. +MS (ESI) m/z: 420.0 (420.9).

pan class="Gene">(E)-1-(4-chlorobenzyl)-4-((4-(4-chlorostyryl)phenoxy)methyl)-1H-1,2,3-triazole (7u). White crystals, IR (KBr) ν: = 3059, 2937, 1606, 1514, 1492, 1258 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 5.15 (2H, s, –CH2-), 5.61 (2H, s, –OCH2-), 7.05 (2H, d, J = 8.8 Hz, Ar–H), 7.11 (1H, d, J = 16.8 Hz, styryl –CH=C-), 7.24 (1H, d, J = 16.8 Hz, styryl –C=CH-), 7.34 (2H, d, J = 8.4 Hz, Ar–H), 7.38–7.46 (4H, dd, J = 8.8, 8.8 Hz, Ar–H), 7.52–7.59 (4H, dd, J = 8.4, 8.8 Hz, Ar–H), 8.20 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 52.01, 61.11, 124.74, 124.97, 127.78, 127.88, 128.61, 128.75, 128.86, 129.77, 129.89, 131.39, 132.86, 134.98, 136.34, 142.95, 157.86. +MS (ESI) m/z: 437.0 (437.3).

pan class="Gene">(E)-1-(4-chlorobenzyl)-4-((4-(4-methylstyryl)phenoxy)methyl)-1H-1,2,3-triazole (7v). White crystals, IR (KBr) ν: = 3087, 2921, 1604, 1514, 1459, 1336, 1253 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 2.29 (3H, s, –CH3), 5.15 (2H, s, –CH2-), 5.61 (2H, s, –OCH2-), 7.02 (2H, d, J = 8.8 Hz, Ar–H), 7.06 (1H, d, J = 16 Hz, styryl –CH=C-), 7.10 (1H, d, J = 16 Hz, styryl –C=CH-), 7.17 (2H, d, J = 7.6 Hz, Ar–H), 7.36 (2H, d, J = 8.4 Hz, Ar–H), 7.45 (4H, d, J = 8.4 Hz, Ar–H), 7.51 (2H, d, J = 8.8 Hz, Ar–H), 8.27 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 20.78, 51.99, 61.10, 114.95, 124.71, 126.09, 126.25, 126.93, 127.85, 128.74, 129.23, 129.88, 130.16, 132.85, 134.53, 134.97, 136.51, 143.0, 157.54. +MS (ESI) m/z: 416.1 (416.9).

pan class="Gene">(E)-1-(4-chlorobenzyl)-4-((4-(4-methoxystyryl)phenoxy)methyl)-1H-1,2,3-triazole (7w). White amorphous mass, IR (KBr) ν: = 3077, 2841, 1606, 1516, 1388, 1251 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 3.76 (3H, s, –OCH3), 5.14 (2H, s, –CH2-), 5.61 (2H, s, –OCH2-), 6.93 (2H, d, J = 8.8 Hz, Ar–H), 7.00–7.03 (4H, m, Ar–H), 7.34 (2H, d, J = 8.4 Hz, Ar–H), 7.45 (2H, d, J = 8.4 Hz, Ar–H), 7.50 (4H, d, J = 8.8 Hz, Ar–H), 8.28 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 51.99, 55.10, 61.10, 114.10, 114.94, 124.68, 125.68, 125.99, 127.36, 128.74, 129.88, 129.96, 130.37, 132.85, 134.97, 143.02, 157.35, 158.64. +MS (ESI) m/z: 432.1 (432.9).

pan class="Gene">(E)-1-(4-chlorobenzyl)-4-((4-(4-nitrostyryl)phenoxy)methyl)-1H-1,2,3-triazole (7x). Yellow crystals, IR (KBr) ν: = 3089, 2826, 1634, 1587, 1509, 1427, 1217 cm−1. 1H NMR (400 MHz, DMSO-d6): δ = 5.18 (2H, s, –CH2-), 5.62 (2H, s, –OCH2-), 7.09 (2H, d, J = 8.8 Hz, Ar–H), 7.29 (1H, d, J = 16.4 Hz, styryl –CH=C-), 7.35 (2H, d, J = 8.4 Hz, Ar–H), 7.45 (2H, d, J = 8.4 Hz, Ar–H), 7.50 (1H, d, J = 16.4 Hz, styryl –C=CH-), 7.63 (2H, d, J = 8.8 Hz, Ar–H), 7.83 (2H, d, J = 8.8 Hz, Ar–H), 8.22 (2H, d, J = 8.8 Hz, Ar–H), 8.29 (1H, s, Triazole-H). 13C NMR (400 MHz, DMSO-d6): δ = 52.02, 61.14, 115.11, 124.23, 124.83, 126.92, 128.63, 128.79, 129.27, 129.93, 132.96, 134.35, 135.01, 142.88, 144.49, 145.82, 158.56. +MS (ESI) m/z: 447.1 (447.9).

Bio-evaluation

Cytostatic assays

All pan class="Disease">tumor cell lines were acquired from the American Type Culture Collection (ATCC, Manassas, VA, USA), except for the DND-41 cell line, which was purchased from Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ Leibniz-Institut, Braunschweig, Germany). All cell lines were cultured as recommended by the suppliers. Media were purchased from GIBCO Life Technologies, USA, and supplemented with 10% fetal bovine serum (HyClone, GE Healthcare Life Sciences, USA). For real-time monitoring, adherent cell lines HCT-116, NCI–H460, and Capan-1 were seeded at a density between 500 and 1500 cells per well in 384-well clear-bottomed tissue culture plates (Greiner). After overnight incubation, cells were treated with the test compounds at seven different concentrations ranging from 100 to 6.4 × 10−3 μM. Suspension cell lines K-562, Z-138, and DND-41 were seeded at densities ranging from 2500 to 5000 cells per well in 384-well clear-bottomed tissue culture plates containing the test compounds at the same seven concentration points. The plates were incubated and monitored at 37 °C for 72 h in the IncuCyte® system (Essen BioScience Inc., Ann Arbor, MI, USA) for real-time imaging. Images were taken every 3 h, with one field imaged per well under 10× magnification. Cell growth was then quantified based on percent cellular confluence as analyzed by the IncuCyte® image analysis software and used to determine the IC50 values.

Methodology for in silico studies

The 3D structures of all compounds were prepared using Avogadro v1.2.0 [28] and their energies were minimized with the MMFF94s force field. The pan class="Chemical">ADME properties, pharmacokinetic properties, and drug-likenesses of the compounds were then investigated with the SwissADME webserver [22, 23]. Finally, docking simulations of all compounds were performed with the crystal structure of a tubulin heterodimer (PDB ID: 1TUB) [24]. All ligands and the target were prepared using PyRx software [29] and the docking experiments were subsequently carried out using AutoDock Vina software [30] with the Lamarckian genetic algorithm (LGA) [31, 32]. The visualizations of docking simulation results were conducted using the Discovery studio [33].

Results and discussion

Chemistry

Series of pan class="Gene">(E)-1-benzyl-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazoles (7a-x) were obtained by Wittig reaction (Figure 2) [34] between the respective 4-((1-benzyl-1H-1,2,3-triazol-4-yl)methoxy) benzaldehydes (5a-d) and benzyltriphenylphosphonium halides (chlorides and bromide) (6a-f). Compounds 5a-d were obtained via copper (Cu)-catalyzed regioselective 1,3-dipolar cycloaddition of 4-(prop-2-ynyloxy)benzaldehyde (3) with benzyl azides (4a-d), while the reaction between 4-hydroxybenzaldehyde (1) and propargyl bromide (2) led to compound 3. Schemes 1a-c represent the synthetic routes and Table 1 contains the structures of 7a-x. Structural confirmation was performed with Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry.

Figure 2

Mechanism of synthesis for 7a-x.

Scheme 1

a. Synthesis of 4-(prop-2-yn-1-yloxy)benzaldehyde (3). b. Synthesis of 4-((1-benzyl-1H-1,2,3-triazol-4-yl)methoxy)benzaldehydes (5a-d). c. Synthesis of (E)-1-benzyl-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazoles (7a-x).

Table 1

Synthesized stilbene linked 1,2,3-triazole analogues (7a-x).

Image 1
Compound	R1	R	Molecular weight	Molecular formula	Melting point (°C)	Yield (%)	Purity (%)
7a	H	H	367.44	C24H21N3O	202–204	35	100
7b	F	H	385.43	C24H20FN3O	180–182	45	100
7c	Cl	H	401.89	C24H20ClN3O	229–230	39	100
7d	CH3	H	381.47	C25H23N3O	102–104	28	100
7e	OCH3	H	397.47	C24H23N3O2	190–192	39	100
7f	NO2	H	412.44	C24H20N4O3	176–177	36	100
7g	H	NO2	412.44	C24H20N4O3	145–147	45	100
7h	F	NO2	430.43	C24H19FN4O3	182–184	32	100
7i	Cl	NO2	446.89	C24H19ClN4O3	190–192	28	100
7j	CH3	NO2	426.47	C25H22N4O3	208–211	42	100
7k	OCH3	NO2	442.47	C25H22N4O4	207–209	28	100
7l	NO2	NO2	457.44	C24H19N5O5	207–208	33	100
7m	H	CH3	381.47	C25H23N3O	174–176	32	100
7n	F	CH3	399.46	C25H22FN3O	204–206	42	100
7o	Cl	CH3	415.91	C25H22ClN3O	187–190	42	100
7p	CH3	CH3	395.50	C26H25N3O	200–202	35	100
7q	OCH3	CH3	411.50	C26H25N3O2	166–168	42	100
7r	NO2	CH3	426.47	C25H22N4O3	148–150	34	91
7s	H	Cl	401.89	C24H20ClN3O	170–171	42	88
7t	F	Cl	419.88	C24H19ClFN3O	170–172	36	100
7u	Cl	Cl	436.33	C24H19Cl2N3O	128–130	35	100
7v	CH3	Cl	415.91	C24H22ClN3O	165–166	42	100
7w	OCH3	Cl	431.91	C25H22ClN3O2	192–194	35	100
7x	NO2	Cl	446.89	C24H19ClN4O3	174–176	39	100

Mechanism of synthesis for pan class="Chemical">7a-x.

a. Synthesis of pan class="Chemical">4-(prop-2-yn-1-yloxy)benzaldehyde (3). b. Synthesis of 4-((1-benzyl-1H-1,2,3-triazol-4-yl)methoxy)benzaldehydes (5a-d). c. Synthesis of (E)-1-benzyl-4-((4-styrylphenoxy)methyl)-1H-1,2,3-triazoles (7a-x).

Synthesized pan class="Chemical">stilbene linked 1,2,3-triazole analogues (7a-x).

The FTIR spectra of compounds pan class="Chemical">7a-x showed stretching peaks in the ranges of 3010–3101 (-CH, ar.), 2734–2964 (-CH, ali.), 1513–1634 (>C=N-), 1507–1516 (>C=C<), and 1176–1266 (-O-) cm−1 for the groups given in parentheses. Methylene (–CH2–) bending peaks appeared in the range of 1427–1492 cm−1. Compounds 7d, 7e, 7j, 7k, 7m-r, 7v, and 7w showed methyl (-CH3) bending peaks in the range of 1336–1395 cm−1, while the nitro (-NO2) stretching in 7f-l, 7r, and 7x appeared between 1514 and 1592 cm−1.

1H NMR spectra showed pan class="Chemical">singlet triazole ring protons in the range of 8.20–8.38 δ ppm. The aromatic protons appeared between 6.93 and 8.25 δ ppm while two doublet peaks appeared in the range of 7.06–7.50 δ ppm for -CH=CH of styryl moiety [35, 36]. Peaks at 5.40–5.80 and 5.13–5.20 δ ppm represent -N–CH2– and –OCH2-, respectively. The –CH3 protons of 7d, 7j, 7m-r, and 7v appeared between 2.27 and 2.29 δ ppm along with -O-CH3 protons of 7e, 7k, 7q, and 7w at 3.76 δ ppm. The nature of the carbon in 7a-x was ascertained by the respective 13C NMR spectral data. Absence of the –C≡CH proton of 3 at 1.56 δ ppm and presence of additional -N–CH2– protons at 5.52 δ ppm along with singlet triazole-H at 7.59 δ ppm in 5a confirmed the reaction between 3 and 4a. Table 1 contains details of compounds 7a-x such as molecular weight, molecular formula, yield, percentage purity, and physical constant.

Biological study

In vitro cellular pan class="Disease">cytotoxicity evaluations of derivatives 7a-x were performed using six different human cancer cell lines (Capan-1, HCT-116, NCI–H460, DND-41, K-562, and Z-138) in 384-well micro-titer plates [37]. The tubulin inhibitor docetaxel [38] and the pan-kinase inhibitor staurosporine (STS) [39] were used as reference compounds and dimethyl sulfoxide (DMSO) as a solvent. The cytotoxicity data summarized in Table 2 represent 50% inhibitory concentrations (IC50).

Table 2

In-vitro cytotoxicity data of synthesized stilbene linked 1,2,3-triazoles 7a-x (μM).

Compound	Capan-1	HCT-116	NCI–H460	DND-41	K-562	Z-138
	Pancreatic adeno-carcinoma	Colorectal carcinoma	Lung carcinoma	Acute lymphoblastic leukemia	Chronic myeloid leukemia	Non-Hodgkin lymphoma
7a	46.7	29.1	34.3	61.4	39.9	>100
7b	30.7	46.7	31.7	>100	>100	>100
7c	96.4	36.1	>100	>100	19.3	>100
7d	>100	>100	81.7	>100	>100	60.3
7e	55.3	13.5	35.1	>100	>100	>100
7f	45.3	62.4	40.7	>100	>100	>100
7g	>100	26.1	78.5	82.1	>100	>100
7h	40.2	12.2	11.6	>100	>100	>100
7i	62.3	21.3	31.3	>100	>100	>100
7j	62.3	>100	98.3	>100	>100	>100
7k	50.2	12.6	95.4	>100	>100	>100
7l	70.3	76.7	44.3	>100	>100	>100
7m	45.9	>100	41.7	>100	>100	>100
7n	73.4	>100	>100	>100	>100	>100
7o	51.8	>100	47.3	81.2	>100	>100
7p	52.4	87.4	60.8	>100	>100	>100
7q	34.6	30.5	37.1	>100	>100	>100
7r	39.5	21.3	16.2	>100	>100	>100
7s	80.6	33	61.1	>100	>100	>100
7t	67.3	71.5	91.9	>100	>100	>100
7u	41.3	36.5	33.8	>100	>100	>100
7v	>100	57.3	>100	>100	>100	>100
7w	48.9	36	12.4	>100	>100	>100
7x	>100	55.8	72.5	>100	>100	>100
Docetaxel	0.0063	0.0008	0.0001	0.0019	0.0034	0.0019
STS	0.0046	0.0003	0.0032	0.0064	0.0298	0.0003

In-vitro pan class="Disease">cytotoxicity data of synthesized stilbene linked 1,2,3-triazoles 7a-x (μM).

Irrespective of the substituents on the aromatic ring system, compounds pan class="Chemical">7a-x were found to be poorly cytotoxic towards acute lymphoma (DND-41), chronic myeloid leukemia (K-562), Non Hodgin lymphoma (Z-138) and moderate cytotoxic against pancreatic adeno carcinoma (Capan-1), colorectal carcinoma (HCT-116), lung carcinoma (NCI–H460). In general, among the tested derivatives, 7a and 7c showed some cytotoxic chronic myeloid leukemia (K-562) cells. Most of the compounds displayed some sort of cytotoxic activity 31–96 μM against pancreatic adeno carcinoma (Capan-1) cells except compounds 7d, 7g, 7v and 7x. For colorectal carcinoma cells (HCT-116), the cytotoxic activity exhibited by many compounds of the series ranging from 12-87 μM. Among this series, 7e, 7h and 7k were the most potent with IC50 at 12–13 μM, many compounds such as 7a, 7g, 7i, 7q and 7r were cytotoxic in the range of 20–30 μM. For lung carcinoma (NCI–H460) cells, 12–16 μM cytotoxicity activity showed by compounds 7h, 7r and 7w, whereas remaining compounds exhibited the activity ˃30 μM. In case of acute lymphoblastc leukemia (DND-41), very limited compounds namely 7a, 7g and 7o displayed some cytotoxic activity 60–80 μM, remaining all compounds did not display any cytotoxic activity. Even for the chronic myeloid leukemia (K-562) cells also not showed any activity by the synthesized compounds except 7a and 7c with 40 and 19 μM. Similarly, for Non Hodgin lymphoma (Z-138), one compound that is 7d showed some cytotoxic activity with IC50 60μM, and remaining compounds in the series failed to display activity. By looking at the cytotoxicity results from Table 2, the most of the compounds tested in the series were cytotoxic only against carcinoma cells but not active or cytotoxic to leukemia and lymphoma but none of the tested compounds was not potent as compared to both the drug standards. The compounds shown in Figure 3 are the most active members of the series.

Figure 3

Biologically active stilbene linked 1,2,3-triazole derivatives.

Biologically activpan class="Chemical">e stilbene linked pan class="Chemical">1,2,3-triazole derivatives.

In silico analyses

Table 3 shows the physicochemical properties, pan class="Chemical">ADME parameters, and violations of drug-likeness rules of the synthesized compounds. Calpan class="Chemical">culated physicochemical and lipophilicity parameters are used by various filters to evaluate the drug-likeness of synthesized compounds and, in this paper, we evaluated the drug-likeness properties of the compounds with the most significant filtering approaches in the literature. The filters used here and their rules are as follows:

Table 3

Physicochemical and pharmacokinetic properties of stilbene linked 1,2,3-triazoles.

Comp.	Binding affinity	Physicochemical Properties							Lipophilicity						Drug-likeness					Water Solubility		Pharmacokinetics
		MW (g/mol)	Fsp3	RB	HBA	HBD	MR	tPSA	ilogP	XlogP3	WlogP	MlogP	SILICOS-IT	Consensus logP	Lipinski	Ghose	Veber	Egan	Muegge	ESOL	Class	Log Kp (cm/s)	F
7a	-10.3	367.44	0.08	7	3	0	112.12	39.94	3.83	5.05	4.71	4.01	4.86	4.49	0	0	0	0	1	-5.45	Moderately	-4.96	0.55
7b	-9.9	385.43	0.08	7	4	0	112.08	39.94	3.84	5.15	5.27	4.38	5.27	4.78	1	0	0	0	1	-5.60	Moderately	-4.99	0.55
7c	-10.6	401.89	0.08	7	3	0	117.13	39.94	4.18	5.68	5.36	4.49	5.49	5.04	1	0	0	0	1	-6.04	Poorly	-4.72	0.55
7d	-10.4	381.47	0.12	7	3	0	117.09	39.94	4.03	5.42	5.01	4.22	5.38	4.81	1	0	0	0	1	-5.74	Moderately	-4.78	0.55
7e	-10.3	397.47	0.12	8	4	0	118.61	49.17	4.23	5.03	4.71	3.66	4.91	4.51	0	0	0	0	1	-5.51	Moderately	-5.15	0.55
7f	-10.1	412.44	0.08	8	5	0	120.94	85.76	3.50	4.88	4.61	3.86	2.68	3.91	0	0	0	0	0	-5.49	Moderately	-5.35	0.55
7g	-9.7	412.44	0.08	8	5	0	120.94	85.76	3.53	4.88	4.61	3.86	2.68	3.91	0	0	0	0	0	-5.49	Moderately	-5.35	0.55
7h	-11.2	430.43	0.08	8	6	0	120.90	85.76	3.55	4.98	5.17	4.24	3.10	4.21	1	0	0	0	0	-5.65	Moderately	-5.39	0.55
7i	-10.2	446.89	0.08	8	5	0	125.95	85.76	3.74	5.51	5.27	4.34	3.32	4.44	1	0	0	0	1	-6.09	Poorly	-5.11	0.55
7j	-10.5	426.47	0.12	8	5	0	125.91	85.76	3.84	5.25	4.92	3.26	3.21	4.10	0	0	0	0	1	-5.80	Moderately	-5.17	0.55
7k	-10.3	442.47	0.12	9	6	0	127.43	94.99	3.72	4.85	4.62	2.74	2.75	3.74	0	0	0	0	0	-5.56	Moderately	-5.56	0.55
7l	-10.1	457.44	0.08	9	7	0	129.76	131.58	3.29	4.71	4.52	3.01	0.53	3.21	0	0	0	0	0	-5.55	Moderately	-5.75	0.55
7m	-9.6	381.47	0.12	7	3	0	117.09	39.94	4.09	5.42	5.01	4.22	5.38	4.83	1	0	0	0	1	-5.74	Moderately	-4.78	0.55
7n	-10.2	399.49	0.12	7	4	0	117.04	39.94	4.28	5.52	5.57	4.59	5.80	5.15	1	0	0	0	1	-5.90	Moderately	-4.82	0.55
7o	-10.2	415.91	0.12	7	3	0	122.10	39.94	4.42	6.05	5.67	4.69	6.02	5.37	1	1	0	0	1	-6.34	Poorly	-4.54	0.55
7p	-10.5	395.50	0.15	7	3	0	122.05	39.94	4.27	5.78	5.32	4.42	5.91	5.14	1	0	0	0	1	-6.04	Poorly	-4.61	0.55
7q	-10.5	411.50	0.15	8	4	0	123.58	49.17	4.54	5.39	5.02	3.86	5.44	4.85	0	0	0	0	1	-5.81	Moderately	-4.98	0.55
7r	-10.9	426.47	0.12	8	5	0	125.91	85.76	3.87	5.25	4.92	3.26	3.21	4.10	0	0	0	0	1	-5.80	Moderately	-5.17	0.55
7s	-9.3	401.89	0.08	7	3	0	117.13	39.94	4.14	5.68	5.36	4.49	5.49	5.03	1	0	0	0	1	-6.04	Poorly	-4.72	0.55
7t	-9.7	419.88	0.08	7	4	0	117.09	39.94	4.21	5.78	5.92	4.86	5.91	5.33	1	1	0	1	1	-6.19	Poorly	-4.76	0.55
7u	-10.0	436.33	0.08	7	3	0	122.14	39.94	4.34	6.31	6.01	4.96	6.13	5.55	1	1	0	1	1	-6.63	Poorly	-4.48	0.55
7v	-10.2	415.91	0.12	7	3	0	122.10	39.94	4.27	6.05	5.67	4.69	6.02	5.34	1	1	0	0	1	-6.34	Poorly	-4.54	0.55
7w	-10.4	431.91	0.12	8	4	0	123.62	49.17	4.44	5.65	5.37	4.13	5.55	5.03	0	0	0	0	1	-6.10	Poorly	-4.92	0.55
7x	-10.5	446.89	0.08	8	5	0	125.95	85.76	3.73	5.51	5.27	4.34	3.32	4.43	1	0	0	0	1	-6.09	Poorly	-5.11	0.55
Docetaxel	-9.4	807.88	0.56	14	14	5	205.25	224.45	4.30	2.81	2.94	1.06	3.51	2.92	2	3	2	1	3	-5.85	Moderately	-9.23	0.17
STS	-10.8	466.53	0.32	2	4	2	139.39	69.45	3.19	3.24	3.39	2.60	3.02	3.09	0	1	0	0	1	-5.06	Moderately	-6.85	0.55

Molecular weight: MW, topological polar surface area: tPSA, Molar Refractivity: MR, fraction of sp3 carbon atoms: Fsp3, HBD: hydrogen bonds donor, HBA: hydrogen bond acceptor, RB: rotatable bonds, LogP values: indicator of Lipophilicity, ESOL: aqueous solubility parameter, Log Kp: skin permeation, F: Bioavailability Score.

Lipinski (Pfizer) filter [40]: MW ≤ 500; MLOGP ≤4.15; HBA ≤10; pan class="Gene">HBD ≤5

Ghose filter [41]: 160 ≤ MW ≤ 480; -0.4 ≤ WLOGP ≤5.6; 40 ≤ MR ≤ 130; 20 ≤ atoms ≤70

Veber (GSK) filter [42]: RB ≤ 10; TPSA ≤140

Egan (Pharmacia) filter [43]: WLOGP ≤5.88; TPSA ≤131.6

Muegge (Bayer) filter [44]: 200 ≤ MW ≤ 600, -2 ≤ XLOGP ≤5; TPSA ≤157; HBA ≤10; pan class="Gene">HBD ≤5; RB ≤ 15; number of rings ≤7; number of pan class="Chemical">carbons >4; number of heteroatoms >1.

Physicochemical and pharmacokinetic properties of pan class="Chemical">stilbene linked pan class="Chemical">1,2,3-triazoles.

Molepan class="Chemical">cular weight: MW, topological polar surface area: tPSA, Molar Refractivity: MR, fraction of sp3 carbon atoms: Fsp3, HBD: hydrogen bonds donor, HBA: hydrogen bond acceptor, RB: rotatable bonds, LogP values: indicator of Lipophilicity, ESOL: aqueous solubility parameter, Log Kp: skin permeation, F: Bioavailability Score.

The filters generally assume that an orally active drug should not violate the above criteria more than once. When Table 3 is examined, it can be said that all newly synthesized compounds and the reference drug pan class="Chemical">STS meet these criteria. However, the other reference drug, pan class="Chemical">docetaxel, is observed to violate all filters more than once, except the Muegge filter.

pan class="Gene">Fsp3 is another newly introduced parameter [45] to interpret the drug-likeness properties of molecules. According to Table 3, the Fsp3 values of all compounds are lower than those of docetaxel and STS. Furthermore, we observed that the ESOL values of all synthesized compounds belonged to the moderately water-soluble class. Compounds 7c, 7j, 7o, 7p, 7s, 7t, 7u, 7v, 7w, and 7x have values greater than -6; thus, they are in the poorly soluble class. On the other hand, other newly synthesized compounds and reference drugs are in the moderately soluble class. Log Kp in the table is the skin permeation parameter suggested by Potts et al. [46], and a low negative log Kp value of a compound corresponds to higher absorption into human skin. Accordingly, all newly synthesized compounds have higher levels of skin absorption than the reference drugs. In the table, the bioavailability score (F) of the compounds signifies the probability that a compound will have oral bioavailability in rats [47]. The newly synthesized compounds and STS have higher F scores than docetaxel.

We also conducted molepan class="Chemical">cular docking simulations to help elucidate the anticancer activities of the synthesized compounds. In the docking simulations, we utilized the crystal structure of the tubulin-docetaxel complex [24] (PDB ID: 1TUB) as the target. The binding affinity values obtained as a result of the docking studies are shown in Table 3. As is seen there, compounds 7h and 7r, which show good cytotoxicity in vitro, have the highest binding energy values. It was also observed that the reference drug STS had a higher binding affinity than the other reference drug, docetaxel, which is also the co-ligand of 1TUB. In this context, to identify the binding regions of 7h, 7r, STS, and docetaxel, we display the two-dimensional (2D) interaction diagrams and 3D interactions between these compounds and 1TUB in Figures 4, 5, 6, and 7.

Figure 4

The 2D and 3D representations of interactions between compound 7h and 1TUB receptor.

Figure 5

The 2D and 3D representations of interactions between compound 7r and 1TUB receptor.

Figure 6

The 2D and 3D representations of interactions between docetaxel (co-ligand) and 1TUB receptor.

Figure 7

The 2D and 3D representations of interactions between STS and 1TUB receptor.

The 2D and 3D representations of interactions between compound 7h and 1pan class="Gene">TUB receptor.

The 2D and 3D representations of interactions between compound 7r and 1pan class="Gene">TUB receptor.

The 2D and 3D representations of interactions between pan class="Chemical">docetaxel (co-ligand) and 1pan class="Gene">TUB receptor.

The 2D and 3D representations of interactions between pan class="Chemical">STS and 1pan class="Gene">TUB receptor.

As seen in Figures 4, 5, 6, and 7, compound 7h has a total of 4 pan class="Chemical">hydrogen bond interactions, including 3 conventional hydrogen bonds (coHB) and 1 carbon hydrogen bond (caHB). Compound 7h also has 3 electrostatic interactions (2 pi-anion (PA), 1 pi-cation (PC)), 5 hydrophobic interactions (1 pi-pi T-shaped (PT), 3 pi-alkyl (PAl)), and 1 halogen interaction. On the other hand, compound 7r has 2 hydrogen bonds (1 coHB, 1 pi-donor hydrogen bond (pdHB)), 3 electrostatic interactions (1 PC, 2 PA), and 9 hydrophobic interactions (2 PT, 6 PAl, 1 Alkyl (Al)).

For reference compounds pan class="Chemical">docetaxel and STS, it can be said that docetaxel has 3 hydrogen bonds (3 coHB, 1 caHB), 1 electrostatic interaction (1 PC), and 8 hydrophobic interactions (1 PT, 2 PAl, 5 Al), whereas STS has 2 hydrogen bonds (3 coHB, 1 caHB), 2 electrostatic interactions (1 PC), and 6 hydrophobic interactions (2 PAl, 4 pi-pi stacked (PSt)). In this case, the PSt interactions of STS may have caused STS to show higher affinity for 1TUB than docetaxel.

Conclusions

24 derivatives of pan class="Chemical">resveratrol linked 1,2,3-triazole (7a-x) were synthesized, characterized by 1H, 13C NMR, Mass Spectrometry and FTIR. All the compounds tested for their cytotoxic study against three carcinoma, two leukemia and one lymphoma human cancer cell lines. Most of the compounds tested in the series were cytotoxic towards all three types of carcinoma cells but were not cytotoxic to leukemia and lymphoma. In the docking simulations, we docked all the compounds with protein 1TUB. Compounds 7h and 7r, which showed good cytotoxicity in vitro, have the highest binding energy values. We identified according to docking results that compound 7h has four hydrogen bond, three electrostatic interactions, five hydrophobic interactions, and one halogen interaction while another compound 7r has two hydrogen bonds, three electrostatic interactions, and nine hydrophobic interactions. Therefore, resveratrol linked 1,2,3-triazoles were more sensitive towards human carcinoma cell lines but least sensitive towards leukemia and lymphoma cell lines. Hence, further optimization is required to obtain an effective lead molecule against cancer.

Declarations

Author contribution statement

A. Das: Performed the experiments; Contributed reagents, materials, analysis tools or data.

D. Daelemans: Performed the experiments.

L. Persoons: Performed the experiments.

D. Schols: Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.

S. S Karki: Conceived and designed the experiments; Analyzed and interpreted the data; Wrote the paper.

S. Kumar: Contributed reagents, materials, analysis tools or data; Wrote the paper.

H. Alici: Conceived and designed the experiments; Performed the experiments; Contributed reagents, materials, analysis tools or data.

H. Tahtaci: Analyzed and interpreted the data; Wrote the paper.

Funding statement

This work was supported by Federal funds from the Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and pan class="Species">Human Services, under Contract No. 75N93019D00005.

Data availability statement

Data will be made available on request.

Declaration of interests statement

The authors declare no conflict of interest.

Additional information

No additional information is available for this paper.