<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">IJOC</journal-id><journal-title-group><journal-title>International Journal of Organic Chemistry</journal-title></journal-title-group><issn pub-type="epub">2161-4687</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/ijoc.2022.122006</article-id><article-id pub-id-type="publisher-id">IJOC-117052</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Biomedical&amp;Life Sciences</subject><subject> Chemistry&amp;Materials Science</subject></subj-group></article-categories><title-group><article-title>
 
 
  Design and Synthesis of Some New Oxadiazole Derivatives as Anticancer Agents
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Mo’men</surname><given-names>Salem</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rezk</surname><given-names>Ayyad</given-names></name><xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Helmy</surname><given-names>Sakr</given-names></name><xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib></contrib-group><aff id="aff2"><addr-line>Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt</addr-line></aff><aff id="aff1"><addr-line>Department of Medicinal Chemistry, Faculty of Pharmacy, Sinai University, Northern Sinai, Egypt</addr-line></aff><pub-date pub-type="epub"><day>19</day><month>04</month><year>2022</year></pub-date><volume>12</volume><issue>02</issue><fpage>64</fpage><lpage>74</lpage><history><date date-type="received"><day>9,</day>	<month>April</month>	<year>2022</year></date><date date-type="rev-recd"><day>7,</day>	<month>May</month>	<year>2022</year>	</date><date date-type="accepted"><day>10,</day>	<month>May</month>	<year>2022</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution-NonCommercial International License (CC BY-NC).http://creativecommons.org/licenses/by-nc/4.0/</license-p></license></permissions><abstract><p>
 
 
  In this work, some new oxadiazole derivatives have been prepared, by reacting phenyl hydrazine and acetic anhydride together, which furnished 2,4-
  dimethyl-4-phenyloxadiazole. This product was reacted with a series of aromatic aldehydes, to obtain a series of oxadiazole derivatives. These derivatives were characterized by TLC, melting points, infrared red, proton nuclear magnetic resonance, carbon thirteen nuclear magnetic resonance and mass spectroscopy. Finally, these synthetized derivatives were tested for antiproliferative activity by two different cell lines. MCF-7 (Breast cancer cell line) and HepG2 (Liver cancer cell line) were used to assess the antiproliferative activity of the prepared compounds.
 
</p></abstract><kwd-group><kwd>Phenyl Hydrazine</kwd><kwd> Oxadiazole</kwd><kwd> Aromatic Aldehydes</kwd><kwd> Acetic Anhydride</kwd><kwd> Benzylidene Synthesis</kwd><kwd> Cytotoxic Assay</kwd><kwd> Anticancer</kwd><kwd> HepG2 and MCF-7</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>Cancer is one of the most challenging public health diseases that face humankind [<xref ref-type="bibr" rid="scirp.117052-ref1">1</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref2">2</xref>]. It is characterized by the development of abnormal cells that divide uncontrollably and have the ability to infiltrate and destroy normal body tissues [<xref ref-type="bibr" rid="scirp.117052-ref1">1</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref2">2</xref>]. The disease is characterized by high morbidity and mortality rates [<xref ref-type="bibr" rid="scirp.117052-ref3">3</xref>]. In many countries, it has become the second largest killer after cardiovascular diseases [<xref ref-type="bibr" rid="scirp.117052-ref3">3</xref>]. In 2012, there were 14 million new cases and 8.2 million deaths [<xref ref-type="bibr" rid="scirp.117052-ref4">4</xref>]. Among men, lung cancer was the most predominant, while among women, it was breast cancer. It was reported that there were 24 million cancer cases annually and 14.6 million annual deaths by the end of 2015 [<xref ref-type="bibr" rid="scirp.117052-ref4">4</xref>]. The previous data led the researchers globally to combat this disease, searching for new anticancer agents having heterocyclic nucleus is having a worldwide attention at various laboratories [<xref ref-type="bibr" rid="scirp.117052-ref5">5</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref6">6</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref7">7</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref8">8</xref>]. It was reported that heterocyclic compounds could have anti-antiproliferative activities, with different proposed mechanisms of action [<xref ref-type="bibr" rid="scirp.117052-ref5">5</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref9">9</xref>]. The anticancer activity of these compounds may be due to their intercalating properties or covalent binding abilities to DNA [<xref ref-type="bibr" rid="scirp.117052-ref9">9</xref>] or cell membrane interaction [<xref ref-type="bibr" rid="scirp.117052-ref10">10</xref>]. Many of the drugs being used in chemotherapy have heterocycles as their basic structure, for example, pyrrole, pyrrolidine, pyridine, imidazole, pyrimidines, pyrazole, indole, quinoline, oxadiazole, azole, benzimidazole, etc. as the key building blocks to develop active biological compounds [<xref ref-type="bibr" rid="scirp.117052-ref11">11</xref>]. This research is based on the reaction of phenyl hydrazine with acetic anhydride to obtain 2,4-dimethyl-4-phenyloxadiazole. This product was reacted with a series of aromatic aldehydes, to obtain a series of oxadiazole derivatives. The reaction was performed at one site of the two active methylene groups and this is most likely because of the steric hindrance maintained by the phenyl group of the phenyl hydrazine [<xref ref-type="bibr" rid="scirp.117052-ref12">12</xref>] - [<xref ref-type="bibr" rid="scirp.117052-ref27">27</xref>].</p></sec><sec id="s2"><title>2. Materials</title><sec id="s2_1"><title>2.1. Reagents</title><p>All solvents and reagents were obtained from commercial sources and were used without further purification except petroleum ether and ethyl acetate. phenyl Hydrazine was purchased from Sigma Aldrich (Cairo, Egypt). Series of aromatic aldehydes were acquired from Sigma Aldrich (Cairo, Egypt). Absolute ethanol, ethanol 95%, acetic anhydride, ethyl acetate and petroleum ether were purchased from Piochem (Cairo, Egypt). Distilled water was used for the experiments.</p></sec><sec id="s2_2"><title>2.2. Instruments</title><p>Progress of chemical reactions was observed using TLC (Merck, silica gel plates 60 F254) and visualized using a UV-Vis spectrometer at 254 nm. Melting points were determined by Mel-Temp apparatus. NMR spectra were performed in Chloroform (7.26 ppm), with trimethyl silane as an internal standard, using Bruker Avance 500 spectrometer at ambient temperature, at drug discovery unit, Faculty of Pharmacy, Ain Shams University (ASU, Cairo, Egypt). All chemical shifts were expressed in parts per million (δ), and coupling constants (J) in Hz. FTIR spectra were recorded using KBr pellets on a model 883 double beam infrared spectrophotometer Bruker in 200 - 4000 cm<sup>−1</sup>, at drug discovery unit, Faculty of Pharmacy, Ain Shams University (ASU, Cairo, Egypt). MS spectra were recorded using a Bruker Esquire 2000 by APC or ES ionization, at drug discovery unit, Faculty of Pharmacy, Ain Shams University (ASU, Cairo, Egypt).</p></sec><sec id="s2_3"><title>2.3. Cell Culture: HepG2, MCF-7</title><p>Cell line was obtained from Nawah Scientific Inc., (Mokatam, Cairo, Egypt). Cells were maintained in DMEM media supplemented with 100 mg/mL of streptomycin, 100 units/mL of penicillin and 10% of heat-inactivated fetal bovine serum in humidified, 5% (v/v) CO<sub>2</sub> atmosphere at 37˚C [<xref ref-type="bibr" rid="scirp.117052-ref28">28</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref29">29</xref>].</p></sec><sec id="s2_4"><title>2.4. Cytotoxicity Assay: HepG2, MCF-7</title><p>Cell viability was assessed by SRB assay. Aliquots of 100 μL cell suspension (5 &#215; 10<sup>3</sup> cells) were in 96-well plates and incubated in complete media for 24 h. Cells were treated with another aliquot of 100 μL media containing drugs at various concentrations. After 72 h of drug exposure, cells were fixed by replacing media with 150 μL of 10% TCA and incubated at 4˚C for 1 h. The TCA solution was removed, and the cells were washed 5 times with distilled water. Aliquots of 70 μL SRB solution (0.4% w/v) were added and incubated in a dark place at room temperature for 10 min. Plates were washed 3 times with 1% acetic acid and allowed to air-dry overnight. Then, 150 μL of TRIS (10 mM) was added to dissolve protein-bound SRB stain; the absorbance was measured at 540 nm using a BMG LABTECH&#174;-FLUOstar Omega microplate reader (Ortenberg, Germany) [<xref ref-type="bibr" rid="scirp.117052-ref28">28</xref>] [<xref ref-type="bibr" rid="scirp.117052-ref29">29</xref>].</p></sec></sec><sec id="s3"><title>3. Chemistry and Scheme</title><sec id="s3_1"><title>3.1. Scheme</title><p>General scheme for the synthesis of compound (2) and compounds (14-22), illustrated in <xref ref-type="fig" rid="fig1">Figure 1</xref>.</p></sec><sec id="s3_2"><title>3.2. Procedure and Synthesis of Compound (2): 2,5-Dimethyl-3-Phenyl-1,3,4-Oxadiazolidine</title><p>Mixture of phenyl hydrazine (20 ml, 22 gm, 0.202 mole) and acetic anhydride were stirred together for 24 hours under reflux conditions at 125˚C as described in (<xref ref-type="fig" rid="fig1">Figure 1</xref>). TLC was made by 3:2 Petroleum Ether: Ethyl Acetate system. Precipitate was obtained by the concentration of acetic anhydride layer. Then it was</p><p>crystallized by using absolute ethanol. Yield 88%. m.p = 122˚C.<sup> 1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 1.25 ppm (d, CH<sub>3</sub>), 1.79 ppm (d, CH<sub>3</sub>), 4.5 ppm (q, CH), 4.92 ppm (q, CH), 6.87 - 7.29 ppm (m, aromatic protons) and 10.3 ppm (d, -NH-). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (154.4 ppm), C2 (130.2 ppm), C3 (114.2 ppm), C4 (123.8 ppm), C5 (114.2 ppm), C6 (130.2 ppm), C7 (104.6 ppm), C8 (95.7 ppm), C9 (23.1 ppm) and C10 (27.4 ppm).</p></sec><sec id="s3_3"><title>3.3. Procedure and Synthesis of Compounds (14-22)</title><p>Mixture of 2 (2 gm, 0.011 mole) and series of aromatic aldehydes were mixed together for 12 - 29 hours under refluxing absolute ethanol at 105˚C. With the presence of 0.5 ml H<sub>2</sub>SO<sub>4</sub> as a catalyst as mentioned in (<xref ref-type="fig" rid="fig1">Figure 1</xref>). TLC was made by 1:2 Petroleum Ether: Ethyl Acetate system. Product was obtained from the organic layer, later on, water was added which retrieved more amounts of the product. Crystallization was performed by ethanol to obtain pure crystallized product.</p><sec id="s3_3_1"><title>3.3.1. Compound 14: (Z)-2-Methyl-3-Phenyl-5-Styryl-2,3-Dihydro-1,3,4-Oxadiazole</title><p>Yield: 85%. m.p = 200˚C - 202˚C. <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 3.1 ppm (d, CH<sub>3</sub>), 4.9 ppm (d, -CH-), 5.3 ppm (d, -CH-), 6.8 ppm (q, -CH-O) and 6.95 - 7.7 ppm (m, aromatic).<sup> 13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (131.5 ppm), C2 (129.5 ppm), C3 (127.8 ppm), C4 (137 ppm), C5 (127.8 ppm), C6 (129.5 ppm), C7 (142.5 ppm), C8 (121.3 ppm), C9 (149.2 ppm), C10 (90.9 ppm), C11 (38.6 ppm), C1 (147.5 ppm), C2 (115 ppm), C3 (130 ppm), C4 (125 ppm), C5 (130 ppm) and C6 (115 ppm).</p></sec><sec id="s3_3_2"><title>3.3.2. Compound 15: 2-Methyl-3-Phenyl-5-((1Z,3E)-4-Phenylbuta-1,3-Dien-1-Yl)-2,3- Dihydro-1,3,4-Oxadiazole</title><p>Yield: 82.9%. m.p = 210˚C - 212˚C. IR: 672 cm<sup>−1</sup> (C-H, bending), 699.52 cm<sup>−1</sup> (aromatic, bending), 1002 cm<sup>−1</sup> (C-O, stretching), 1067.33 cm<sup>−1</sup> (C-N, stretching), 1397 cm<sup>−1</sup> (C-H, bending), 1547 cm<sup>−1</sup> (C=C, aromatic), 1630 cm<sup>−1</sup> (C=C, stretching), 1689 cm<sup>−1</sup> (C=N, stretching), 2432 cm<sup>−1</sup> (aromatic, overtone), 2878 cm<sup>−1</sup> (C-H, stretching), 3048 cm<sup>−1</sup> (C-H, aromatic) and 3085 cm<sup>−1</sup> (C-H, stretching).<sup> 1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 2.8 ppm (d, CH3), 5.1 (q, -CH-O-), 5.4 ppm (d, -CH-), 5.9 ppm (t, -CH-), 6.5 ppm (t, -CH-), 6.6 ppm (d, -CH-) and 6.8 - 7.6 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (132.5 ppm), C2 (129.5 ppm), C3 (128 ppm), C4 (136.8 ppm), C5 (128 ppm), C6 (129.5 ppm), C7 (143.5 ppm), C8 (123.3 ppm), C9 (146.2 ppm), C10 (119.8 ppm), C11 (149.5 ppm), C12 (90.2 ppm), C13 (22.4), C1 (146.5 ppm), C2 (116.7 ppm), C3 (129.4 ppm), C4 (125 ppm), C5 (129.4 ppm) and C6 (116.7 ppm).</p></sec><sec id="s3_3_3"><title>3.3.3. Compound 16: (E)-5-(4-Methoxystyryl)-2-Methyl-3-Phenyl-2,3-Dihydro-1,3,4- Oxadiazole</title><p>Yield 86%. m.p = 223˚C. <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 2.1 ppm (d, CH<sub>3</sub>), 3.8 ppm (s, CH<sub>3</sub>), 4.9 (q, -CH-O-), 5.9 ppm (d, -CH-), 6.5 ppm (d, -CH-), and 6.7 - 7.9 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (55.8) ppm), C2 (156.5 ppm), C3 (120.1 ppm), C4 (128.7 ppm), C5 (126.8 ppm), C6 (128.7 ppm), C7 (120.1 ppm), C7 (143.5 ppm), C8 (142.1 ppm), C9 (119.6 ppm), C10 (149.5 ppm), C11 (84.6 ppm), C12 (29.4), C1 (146.1 ppm), C2 (118.7 ppm), C3 (126.4 ppm), C4 (121 ppm), C5 (126.4 ppm) and C6 (118.7 ppm).</p></sec><sec id="s3_3_4"><title>3.3.4. Compound 17: (E)-5-(2-Chlorostyryl)-2-Methyl-3-Phenyl-2,3-Dihydro-1,3,4- Oxadiazole</title><p>Yield 83%. m.p = 205˚C. <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 1.7 ppm (d, CH<sub>3</sub>), 4.7 (q, -CH-O-), 5.8 ppm (d, -CH-), 6.9 ppm (d, -CH-), and 6.9 - 7.5 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (129.9 ppm), C2 (129.1 ppm), C3 (137 ppm), C4 (135.8 ppm), C5 (127.8 ppm), C6 (126.5 ppm), C7 (140.5 ppm), C8 (125.3 ppm), C9 (149.3 ppm), C10 (89.2 ppm), C11 (27.9 ppm), C1 (145.5 ppm), C2 (116.1 ppm), C3 (129.9 ppm), C4 (120.8 ppm), C5 (129.9 ppm) and C6 (116.1 ppm). MS: m/z: 298.07 (100.0%), (M + 1) 299.06 (87.2%), (M + 2) 297.05 (12.8%).</p></sec><sec id="s3_3_5"><title>3.3.5. Compound 18: (E)-5-(4-Chlorostyryl)-2-Methyl-3-Phenyl-2,3-Dihydro-1,3,4- Oxadiazole</title><p>Yield 92%. m.p = 199˚C. IR: 590 cm<sup>−1</sup> (chloride sub., bending), 669 cm<sup>−1</sup> (C-H, bending), 800.52 cm<sup>−1</sup> (aromatic, bending), 710 cm<sup>−1</sup> (mono sub., bending), 1050 cm<sup>−1</sup> (C-O, stretching), 1249.33 cm<sup>−1</sup> (C-N, stretching), 1350 cm<sup>−1</sup> (C-H, bending), 1540 cm<sup>−1</sup> (C=C, aromatic), 1658 cm<sup>−1</sup> (C=C, stretching), 1678 cm<sup>−1</sup> (C=N, stretching), 2413 cm<sup>−1</sup> (aromatic, overtone), 2857 cm<sup>−1</sup> (C-H, stretching), 3035 cm<sup>−1</sup> (C-H, aromatic) and 3095 cm<sup>−1</sup> (C-H, stretching. <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 1.6 ppm (d, CH<sub>3</sub>), 4.3 (q, -CH-O-), 5.2 ppm (d, -CH-), 6.7 ppm (d, -CH-), and 6.8 - 7.9 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl3): δ C1 (130.9 ppm), C2 (129.4 ppm), C3 (133.3 ppm), C4 (133.9 ppm), C5 (133.3 ppm), C6 (129.4 ppm), C7 (142.5 ppm), C8 (122.3 ppm), C9 (153.6 ppm), C10 (85.2 ppm), C11 (29.9 ppm), C1 (142.6 ppm), C2 (116.4 ppm), C3 (129.9 ppm), C4 (121.8 ppm), C5 (129.9 ppm) and C6 (116.4 ppm). MS: m/z: 298.07 (100.0%), (M + 1) 299.06 (63.7%), (M + 2) 297.05 (36.3%).</p></sec><sec id="s3_3_6"><title>3.3.6. Compound 19: 1,4Bis((2)-(5-Methyl-4-Phenyl-4,5-Dihydro-1,3,4-Oxadiazole-2-Yl) Vinyl)Benzene</title><p>Yield 76%. m.p = 295˚C - 297˚C. <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 2.4 ppm (d, CH<sub>3</sub>), 4.89 (q, -CH-O-), 5.95 ppm (d, -CH-), 6.5 ppm (d, -CH-), and 6.6 - 8.1 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (122.9 ppm), C2 (129.1 ppm), C3 (119.3 ppm), C4 (133.9 ppm), C5 (119.3 ppm), C6 (129.1 ppm), C7 (89.6 ppm), C8 (32.1 ppm), C9 (149.6 ppm), C10 (122.8 ppm), C11 (148.7 ppm), C12 (134.4 ppm) and C13 (129.9 ppm).</p></sec><sec id="s3_3_7"><title>3.3.7. Compound 20: (E)-4-(2-(5-Methyl-4-Phenyl-4,5-Dihydro-1,3,4-Oxadiazol-2-Yl) Vinyl)Phenol</title><p>Yield 39%. m.p = 233˚C. IR: 659 cm<sup>−1</sup> (C-H, bending), 798 cm<sup>−1</sup> (aromatic, bending), 708 cm<sup>−1</sup> (mono sub., bending), 1049 cm<sup>−1</sup> (C-O, stretching), 1218 cm<sup>−1</sup> (C-OH, stretching), 1310 cm<sup>−1</sup> (C-N, stretching), 1367 cm<sup>−1</sup> (C-H, bending), 1535 cm<sup>−1</sup> (C=C, aromatic), 1608 cm<sup>−1</sup> (C=C, stretching), 1658 cm<sup>−1</sup> (C=N, stretching), 2460 cm<sup>−1</sup> (aromatic, overtone), 2832 cm<sup>−1</sup> (C-H, stretching), 3055 cm<sup>−1</sup> (C-H, aromatic), 3095 cm<sup>−1</sup> (C-H, stretching) and 3507 cm<sup>−1</sup> (OH, Stretching). <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 1.93 ppm (d, CH<sub>3</sub>), 4.83 (q, -CH-O-), 5.9 ppm (d, -CH-), 6.1 ppm (d, -CH-), 6.9 - 7.5 ppm (m, aromatic) and 9.8 (s, OH). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (159.1 ppm), C2 (135.8 ppm), C3 (119.3 ppm), C4 (129.9 ppm), C5 (119.3 ppm), C6 (135.8 ppm), C7 (149.5 ppm), C8 (123.8 ppm), C9 (149.6 ppm), C10 (90.9 ppm), C11 (21.1 ppm), C1 (145.6 ppm), C2 (120.4 ppm), C3 (109.3 ppm), C4 (121.8 ppm), C5 (109.3 ppm) and C6 (120.4 ppm).</p></sec><sec id="s3_3_8"><title>3.3.8. Compound 21: (E)-2-Methyl-5-(4-Nitrostyryl)-3-Phenyl-2,3-Dihydro-1,3,4-Oxadiazole</title><p>Yield 62%. m.p = 225˚C. <sup>1</sup>HNMR (400 MHz, CDCl<sub>3</sub>): δ 1.24 ppm (d, CH<sub>3</sub>), 4.63 (q, -CH-O-), 6.4 ppm (d, -CH-), 6.8 ppm (d, -CH-) and 6.9 - 8.9 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (155.1 ppm), C2 (132.8 ppm), C3 (125.6 ppm), C4 (143.9 ppm), C5 (125.6 ppm), C6 (132.8 ppm), C7 (144.7 ppm), C8 (129.8 ppm), C9 (149.6 ppm), C10 (90.9 ppm), C11 (27.1 ppm), C1 (143.6 ppm), C2 (125.4 ppm), C3 (115.3 ppm), C4 (121.8 ppm), C5 (115.3 ppm) and C6 (125.4 ppm).</p></sec><sec id="s3_3_9"><title>3.3.9. Compound 22: (E)-2,6-Dimethoxy-4-(2-(5-Methyl-4-Phenyl-4,5-Dihydro-1,3,4- Oxadiazol-2-Yl) Vinyl) Phenol</title><p>Yield 65%. m.p = 280˚C. <sup>1</sup>HNMR (400 MHz, CDCl3): δ 1.98 ppm (d, CH<sub>3</sub>), 3.8 (s, CH<sub>3</sub>), 4.6 (q, -CH-O-), 5.9 ppm (d, -CH-), 6.7 ppm (d, -CH-) and 7.1 - 7.9 ppm (m, aromatic). <sup>13</sup>CNMR (100 MHz, CDCl<sub>3</sub>): δ C1 (139.6 ppm), C2 (149.9 ppm), C3 (114.6 ppm), C4 (126.9 ppm), C5 (114.6 ppm), C6 (14998 ppm), C7 (55.1 ppm), C8 (55.1 ppm), C9 (141.2 ppm), C10 (139.1 ppm), C11 (150.6 ppm), C12 (88 ppm), C13 (22.5 ppm), C1 (143.7 ppm), C2 (129.2 ppm), C3 (116.3 ppm), C4 (120.8 ppm), C5 (116.3 ppm) and C6 (129.2 ppm).</p></sec></sec></sec><sec id="s4"><title>4. Results</title><sec id="s4_1"><title>4.1. Cytotoxicity Results of MCF-7</title><p>MCF-7 cell line was used to assay the antiproliferative activity of compounds 14, 15, 16, 17 and 18, compound 18 was the most potent in this group with IC<sub>50</sub> value of 3.54 μm and compound 16 was the lowest in potency with IC<sub>50</sub> value of 52.67 μm (<xref ref-type="fig" rid="fig2">Figure 2</xref>). Microscopical examination of the tested compounds in the cell line</p><p>at 100 μm used to confirm the calculation of the IC<sub>50</sub> (<xref ref-type="fig" rid="fig3">Figure 3</xref>).</p></sec><sec id="s4_2"><title>4.2. Cytotoxicity Results of HepG2</title><p>HepG2 cell line was used to assay the antiproliferative activity of compounds 19, 20, 21 and 22, compound 19 was the most potent in this group with IC<sub>50</sub> value of 9.38 μm and compound 21 was the lowest in potency with IC<sub>50</sub> value of 32.39 μm (<xref ref-type="fig" rid="fig4">Figure 4</xref>). Microscopical examination of the tested compounds in the cell line at concentration of 100 μm was used to confirm the calculation of the IC<sub>50</sub> (<xref ref-type="fig" rid="fig5">Figure 5</xref>).</p></sec></sec><sec id="s5"><title>5. Conclusion</title><p>From the above findings, we concluded that all assayed compounds have potential antiproliferative activity on both cell lines which were tested. Generally, it was found that the cyclized phenyl hydrazine derivatives (oxodiazoles) are more potent than derivatives with open side chains (not cyclized) [<xref ref-type="bibr" rid="scirp.117052-ref5">5</xref>]. For MCF-7 cell line, compound 18 was found to be the most potent compound in the group scoring 3.548 mm, compound 16 was the lowest in potency scoring 52.67 mm. For HepG2 cell line, compound 19 was found to be the most potent compound</p><p>among the other compounds scoring 9.384 mm and compound 21 was the lowest in potency in this group, scoring 32.39 mm (<xref ref-type="fig" rid="fig6">Figure 6</xref>).</p></sec><sec id="s6"><title>Conflicts of Interest</title><p>The authors declare no conflicts of interest regarding the publication of this paper.</p></sec><sec id="s7"><title>Cite this paper</title><p>Salem, M., Ayyad, R. and Sakr, H. (2022) Design and Synthesis of Some New Oxadiazole Derivatives as Anticancer Agents. International Journal of Organic Chemistry, 12, 64-74. https://doi.org/10.4236/ijoc.2022.122006</p></sec></body><back><ref-list><title>References</title><ref id="scirp.117052-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Bridges, A.J. (2001) Chemical Inhibitors of Protein Kinases. 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