Microwave-Assisted One-Pot Synthesis of Novel Polyarylpyrrole Derivatives of Expected Anticancer Activity

Introduction

One-pot reactions are one of the good green chemistry methods due to the reduction of work-up procedures and purification steps required compared to a more stepwise approach in addition to effect of microwave irradiation on the yield improvement and reduction of reaction time so. The chemistry is greener [1-3]. In reactions that require a catalyst it is possible to combine several catalytic processes in the same reaction vessel [4].

Chalcones are valuable intermediates in organic synthesis and exhibit a multimode of biological activities. The most important feature of chalcones from a chemical point of view, its ability to act as activated α, β-unsaturated carbonyl systems [5-7].

Pyrrole derivatives are considered from one of the most important classes of heterocyclic compounds. They exhibit extensive biological and pharmacological properties [8] such as antimicrobial [9-16] antifungal [17], anti-inflammatory [18-20], antiviral [21], anti-cancer [22,23], anti-hyperglycemic [24,25], anticonvulsant [26], antioxidant [27] and immune suppressant activities [28]. Highly functionalized pyrroles are subunits of heme, chlorophyll, bile pigments, vitamin B12 and pyrrole alkaloids isolated from marine source [29].

A new chemical class of 5-heteroaryl-3-carboxamido-2-substituted pyrrole derivative A was evaluated in vivo and in vitro for antitumor activity and showed promised results. The compound B represented a novel prototype Cdc7 kinase inhibitor [30]. Two compounds C and D exhibited potential cytotoxicity against human non-small cell lung carcinoma cell lines A549 (Figure 1) [31].

Motivated by the fore-mentioned findings, and in continuation of our interest in synthesis of a wide range of heterocyclic systems for biological screening programme using green chemistry tools [32]. We describe here a facile synthesis of polysubstituted pyrroles under microwave irradiation. The structure of the products was confirmed on different analytical and spectroscopic data.

Materials and Methods

Instruments

All melting points were measured on a Gallenkamp melting point apparatus and are uncorrected. The infrared spectra were recorded in potassium bromide disks on a pye Unicam SP 3300 and Shimadzu FT-IR 8101 PC infrared spectrophotometers. The NMR spectra were recorded on a Varian Mercury VXR-300 NMR spectrometer. 1H spectra were run at 300 MHz and 13C spectra were run at 75.46 MHz in dimethyl sulphoxide (DMSO-d6).

Chemical shifts were related to that of the solvent. Mass spectra were recorded on a Shimadzu GCMS-QP 1000EX mass spectrometer at 70 e.V. Elemental analyses were carried out at the Micro analytical Center of Cairo University, Giza, Egypt. Reactions carried out under microwave irradiation were performed in domestic microwave oven using 50 or 100% power.

Materials, solvents and reagents

All organic solvents were purchased from commercial sources and used as received or dried using standard procedures unless otherwise stated. All chemicals were purchased from Merck, Aldrich or across and used without further purification, thin layer chromatography (TLC) was performed on precoated Merck 60GF254 silica gel plates with fluorescent indicator, and detection by means of UV light at 254 and 360 nm.

Organic Synthesis and Reactions

Reaction of chalcones 1(a-e) with different aldehydes 2(a-e)

Conventional method

A mixture of chalcones 1(a-e) (1mmol) [33], and appropriate aldehyde 2(a-e) (1 mmol) in the presence of sodium cyanide (0.18 mmol) and ammonium acetate (1 mmol) was refluxed in DMF for 10 hrs until completion of the reaction (monitored by TLC) to give precipitates which were filtered and recrystallized from ethanol/DMF (1:1) to afford the corresponding derivatives 3(a-y) in 56-72% yield.

Green method

A mixture of chalcones 1(a-e) (1 mmol), and appropriate aldehyde 2(a-e) (1 mmol) in the presence of sodium cyanide (0.18 mmol), ammonium acetate (1 mmol) and 3 ml DMF are mixed in a 10 ml glass vial and subjected to microwave irradiation for 1-2 mins, the solid formed was purified by recrystallization from ethanol/DMF (1:1) affording product identical in all respects (mp, mixed mp and TLC) with 3(a-y) in 92-97% yield.

N-(1-(4-aminophenyl)ethylidene)-4-(4,5-diphenyl-1H-pyrrol-2-yl)aniline (3a)

M.p.=176-178ºC; IR (KBr, cm-1): 1175 (C-N), 1533 (C=C), 1590 (C=N), 3114 (NH), 3260, 3294 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 4.92 (s, 1H, NH), 6.55-7.97 (m, 19H, Ar-H), 10.41 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSOd6): δ 24.52 (CH3C=N), 107.19, 112.91, 118.60, 122.22, 127.58, 129.92, 131.03, 131.91, 137.88, 144.17, 152.30, 154.09 (aromatic), 169.45 (CH3C=N); MS (m/z): 427 (M+); Anal. For C30H25N3 (427.54). (Calcd: C, 84.28; H, 5.89; N, 9.83%; Found: C, 84.32; H, 5.87; N, 9.81%).

N-(1-(4-aminophenyl)ethylidene)-4-(4-phenyl-5-(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3b)

M.p.=160-161ºC; IR (KBr, cm-1): 1178 (C-N), 1317 (C-S), 1513 (C=C), 1597 (C=N), 3055 (NH), 3112, 3186 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 6.04 (s, 1H, NH), 6.55-7.93 (m, 17H, Ar-H), 10.36 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.51 (CH3C=N), 107.53, 112.91, 118.99, 122.53, 125.28, 127.45, 129.93, 131.03, 131.93, 135.52, 141.36, 144.15, 151.71, 154.09 (aromatic), 169.43 (CH3C=N); MS (m/z): 433 (M+); Anal. For C28H23N3S (433.57). (Calcd: C, 77.57; H, 5.35; N, 9.69%; Found: C, 77.59; H, 5.36; N, 9.66%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-(furan-2-yl)-4-phenyl-1H-pyrrol-2-yl)aniline (3c)

M.p.=160-161ºC; IR (KBr, cm-1): 1175 (C-N), 1263 (C-O), 1532 (C=C), 1590 (C=N), 3115 (NH), 3266, 3296 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.53 (s, 1H, NH), 6.55-7.93 (m, 17H, Ar-H), 10.40 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.50 (CH3C=N), 106.35, 108.05, 112.90, 114.14, 118.60, 122.54, 125.27, 127.46, 128.31, 129.93, 131.03, 131.92, 136.70, 141.03, 144.17, 150.86, 153.50, 159.52 (aromatic), 169.35 (CH3C=N); MS (m/z): 417 (M+); Anal. For C28H23N3O (417.50). Calcd: C, 80.55; H, 5.55; N, 10.06%; Found: C, 80.59; H, 5.53; N, 10.04%)

N-(1-(4-aminophenyl)ethylidene)-4-(4-phenyl-5-(pyridin-3-yl)-1H-pyrrol-2-yl)aniline (3d)

M.p.=170-171ºC; IR (KBr, cm-1): 1178 (C-N), 1532 (C=C), 1591 (C=N), 3110 (NH), 3267, 3297 (NH2); 1H NMR (DMSO-d6):δ=2.09 (s, 3H, CH3-C=N-), 5.53 (s, 1H, NH), 6.55-8.34 (m, 18H, Ar-H), 10.37 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 107.78, 112.91, 118.60, 122.54, 124.57, 126.62, 128.04, 129.93, 131.03, 131.93, 135.26, 144.15, 148.56, 152.55, 154.94 (aromatic), 169.35 (CH3C=N); MS (m/z): 428(M+); Anal. For C29H24N4 (428.53). (Calcd: C, 81.28; H, 5.65; N, 13.07%; Found: C, 81.25; H, 5.66; N, 13.09%)

4-(5-(1H-indol-3-yl)-4-phenyl-1H-pyrrol-2-yl)-N-(1-(4-aminophenyl)ethylidene)aniline (3e)

M.p.=176-178ºC; IR (KBr, cm-1): 1178 (C-N), 1528 (C=C), 1591 (C=N), 3110 (NH), 3265, 3296 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.14 (s, 1H, NH), 6.55-8.34 (m, 19H, Ar-H), 9.93 (s, 1H, NH), 10.40 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 105.49, 111.27, 113.07, 116.19, 118.60, 121.23, 122.47, 123.78, 126.02, 128. 30, 129.93, 131.03, 131.92, 134.07, 144.17, 150.01, 152.29 (aromatic), 169.45 (CH3C=N); MS (m/z): 466(M+); Anal. For C32H26N4 (466.58). (Calcd: C, 82.38; H, 5.62; N, 12.01%; Found: C, 82.39; H, 5.60; N, 12.02%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-phenyl-4-(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3f)

M.p.=165-166ºC; IR (KBr, cm-1): 1175 (C-N), 1314 (C-S), 1532 (C=C), 1590 (C=N), 3113 (NH), 3185, 3296 (NH2); 1H NMR (DMSO-d6):δ=2.09 (s, 3H, CH3-C=N-), 5.10 (s, 1H, NH), 7.19-8.09 (m, 17H, Ar-H), 10.41 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.24 (CH3C=N), 100.00, 106.08, 112.91, 118.60, 118.79, 120.72, 122.80, 127.58, 129.15, 129.92, 130.20, 131.91, 132.42, 133.10, 136.54, 140.32, 152.57, 154.60 (aromatic), 169.45 (CH3C=N); MS (m/z): 433 (M+); Anal. For C28H23N3S (433.57). (Calcd: C, 77.57; H, 5.35; N, 9.69%; Found: C, 77.59; H, 5.37; N, 9.65%)

N-(1-(4-aminophenyl)ethylidene)-4-(4,5-di(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3g)

M.p.=158-160ºC; IR (KBr, cm-1): 1176 (C-N), 1318 (C-S), 1527 (C=C), 1592 (C=N), 3106 (NH), 3264, 3295 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.30 (s, 1H, NH), 6.55-8.09 (m, 15H, Ar-H), 10.24 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.39 (CH3C=N), 100.58, 109.24, 113.88, 118.60, 120.72, 129.16, 129.93, 130.21, 131.92, 132.42, 133.12, 136.55, 140.32, 144.16, 151.12, 153.49 (aromatic), 169.36 (CH3C=N); MS (m/z): 439 (M+); Anal. For C26H21N3S2 (439.60). (Calcd: C, 71.04; H, 4.82; N, 9.56%; Found: C, 71.01; H, 4.84; N, 9.57%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-(furan-2-yl)-4-(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3h)

M.p.=154-156ºC; IR (KBr, cm-1): 1175 (C-N), 1263 (C-O), 1315 (C-S), 1530 (C=C), 1591 (C=N), 3111 (NH), 3273, 3295 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 4.90 (s, 1H, NH), 7.18-8.09 (m, 15H, Ar-H), 10.38 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.51 (CH3C=N), 101.42, 106.09, 108.64, 118.60, 118.79, 120.72, 124.24, 128.32, 129.15, 129.92, 130.20, 131.92, 132.42, 133.09, 136.54, 140.32, 144.16, 152.30, 154.99, 159.52 (aromatic), 169.35 (CH3C=N); MS (m/z): 423 (M+); Analysis For C26H21N3OS (423.53). (Calcd: C, 73.73; H, 5.00; N, 9.92%; Found: C, 73.76; H, 5.01; N, 9.88%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-(pyridin-3-yl)-4-(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3i)

M.p.=155-156ºC; IR (KBr, cm-1): 1178 (C-N), 1315 (C-S), 1531 (C=C), 1591 (C=N), 3109 (NH), 3267, 3297 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.27 (s, 1H, NH), 6.55-8.09 (m, 16H, Ar-H), 10.36 (s, 2H, NH2 D2O exchangeable) ; 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 100.24, 108.37, 113.57, 118.22, 123.97, 125.68, 128.31, 129.74, 130.09, 131.52, 133.23, 136.11, 139.58, 148.23, 151.45, 153.49 (aromatic), 169.35 (CH3C=N); MS (m/z): 434 (M+); Anal. For C27H22N4S (434.56). (Calcd: C, 74.63; H, 5.10; N, 12.89%; Found: C, 74.60; H, 5.09; N, 12.93%)

4-(5-(1H-indol-3-yl)-4-(thiophen-2-yl)-1H-pyrrol-2-yl)-N-(1-(4-aminophenyl)ethylidene)aniline (3j)

M.p.=120-122ºC; IR (KBr, cm-1): 1175 (C-N), 1314 (C-S), 1528 (C=C), 1592 (C=N), 3109 (NH), 3182, 3261 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.33 (s, 1H, NH), 6.55-8.28 (m, 17H, Ar-H), 9.93 (s, 1H, NH), 10.38 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.50 (CH3C=N), 100.26, 109.23, 111.26, 113.01, 116.18, 118.60, 121.25, 122.51, 123.83, 124.66, 126.27, 128.33, 129.93, 131.93, 136.70, 137.73, 139.17, 151.45, 153.48 (aromatic), 169.35 (CH3C=N); MS (m/z): 472 (M+); Anal. For C30H24N4S (472.60). (Calcd: C, 76.24; H, 5.12; N, 11.85%; Found: C, 76.22; H, 5.10; N, 11.89%)

N-(1-(4-aminophenyl)ethylidene)-4-(4-(furan-2-yl)-5-phenyl-1H-pyrrol-2-yl)aniline (3k)

M.p.=120-122ºC; IR (KBr, cm-1): 1175 (C-N), 1262 (C-O), 1527 (C=C), 1595 (C=N), 3113 (NH), 3189, 3261 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 4.82 (s, 1H, NH), 6.68-8.06 (m, 17H, Ar-H), 10.45 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.26 (CH3C=N), 100.57, 107.18, 109.90, 113.55, 117.19, 118.61, 119.11, 125.15, 127.13, 129.92, 130.12, 131.91, 132.44, 135.26, 144.17, 146.51, 151.69, 153.75 (aromatic), 169.35 (CH3C=N); MS (m/z): 417 (M+); Anal. For C28H23N3O (417.50). (Calcd: C, 80.55; H, 5.55; N, 10.06%; Found: C, 80.59; H, 5.52; N, 10.05%)

N-(1-(4-aminophenyl)ethylidene)-4-(4-(furan-2-yl)-5-(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3l)

M.p.=126-128ºC; IR (KBr, cm-1): 1174 (C-N), 1261 (C-O), 1327 (C-S), 1526 (C=C), 1595 (C=N), 3112 (NH), 3189, 3260 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.10 (s, 1H, NH), 6.68-8.14 (m, 15H, Ar-H), 10.45 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.51 (CH3C=N), 99.71, 106.35, 108.04, 113.55, 117.19, 118.83, 119.11, 122.81, 129.91, 130.12, 131.90, 132.43, 135.85, 144.20, 146.51, 151.70, 154.60 (aromatic), 169.36 (CH3C=N); MS (m/z): 423 (M+); Anal. For C26H21N3OS (423.53). (Calcd: C, 73.73; H, 5.00; N, 9.92%; Found: C, 73.70; H, 5.01; N,9.94%)

N-(1-(4-aminophenyl)ethylidene)-4-(4,5-di(furan-2-yl)-1H-pyrrol-2-yl)aniline (3m)

M.p.=120-122ºC; IR (KBr, cm-1): 1172 (C-N), 1260 (C-O), 1527 (C=C), 1592 (C=N), 3110 (NH), 3187, 3262 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 4.77 (s, 1H, NH), 6.69-8.07 (m, 15H, Ar-H), 10.39 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 100.99, 106.09, 108.37, 113.56, 117.20, 118.82, 119.11, 123.40, 126.28, 128.31, 129.93, 130.35, 131.92, 132.44, 144.17, 146.52, 151.70, 153.47, 156.96, 159.25 (aromatic), 169.35 (CH3C=N); MS (m/z): 407 (M+); Anal. For C26H21N3O2 (407.46). (Calcd: C, 76.64; H, 5.19; N, 10.31%; Found: C, 76.68; H, 5.17; N, 10.29%)

N-(1-(4-aminophenyl)ethylidene)-4-(4-(furan-2-yl)-5-(pyridin-3-yl)-1H-pyrrol-2-yl)aniline (3n)

M.p.=156-158ºC; IR (KBr, cm-1): 1174 (C-N), 1262 (C-O), 1527 (C=C), 1594 (C=N), 3112 (NH), 3189, 3259 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.12 (s, 1H, NH), 6.57-8.99 (m, 16H, Ar-H), 10.41 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.51 (CH3C=N), 101.42, 106.62, 108.96, 113.56, 117.20, 118.61, 119.11, 123.14, 125.68, 128.57, 129.92, 130.13, 131.92, 132.44, 144.23, 146.52, 151.69, 155.51 (aromatic), 169.50 (CH3C=N); MS (m/z): 418 (M+); Anal. For C27H22N4O (418.49). (Calcd: C, 77.49; H, 5.30; N, 13.39%; Found: C, 77.50; H, 5.32; N, 13.36%)

N-(1-(4-aminophenyl)ethylidene)-4-(4-(furan-2-yl)-5-(1H-indol-3-yl)-1H-pyrrol-2-yl)aniline (3o)

M.p.=124-125ºC; IR (KBr, cm-1): 1172 (C-N), 1257 (C-O), 1525 (C=C), 1591 (C=N), 3109 (NH), 3179, 3259 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.14 (s, 1H, NH), 6.68-8.28 (m, 17H, Ar-H), 9.94 (s, 1H, NH), 10.40 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 100.25, 105.16, 108.03, 112.95, 113.56, 117.20, 118.60, 119.11, 121.27, 122.54, 123.87, 124.61, 126.02, 129.93, 130.14, 131.93, 132.45, 137.61, 139.05, 144.15, 146.51, 151.70, 154.08 (aromatic), 169.35 (CH3C=N); MS (m/z): 456 (M+); Anal. For C30H24N4O (456.54). (Calcd: C, 78.92; H, 5.30; N, 12.27%; Found: C, 78.88; H, 5.32; N, 12.29%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-phenyl-4-(pyridin-3-yl)-1H-pyrrol-2-yl)aniline (3p)

M.p.=280-282 °C; IR (KBr, cm-1): 1181 (C-N), 1533 (C=C), 1592 (C=N), 3100 (NH), 3178, 3249 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.14 (s, 1H, NH), 7.29-9.02 (m, 18H, Ar-H), 10.43 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.51 (CH3C=N), 99.12, 109.23, 114.73, 118.60, 122.55, 124.31, 124.38, 129.92, 130.50, 131.10, 132.26, 135.51, 140.31, 144.18, 144.48, 150.77, 151.36 (aromatic), 169.67 (CH3C=N); MS (m/z): 428 (M+); Anal. For C29H24N4 (428.53). (Calcd: C, 81.28; H, 5.65; N, 13.07%; Found: C, 81.30; H, 5.66; N, 13.04%)

N-(1-(4-aminophenyl)ethylidene)-4-(4-(pyridin-3-yl)-5-(thiophen-2-yl)-1H-pyrrol-2-yl)aniline (3q)

M.p.=210-211ºC; IR (KBr, cm-1): 1183 (C-N), 1314 (C-S), 1536 (C=C), 1591 (C=N), 3099 (NH), 3247, 3296 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 4.70 (s, 1H, NH), 7.48-9.03 (m, 16H, Ar-H), 10.44 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.51 (CH3C=N), 101.43, 108.37, 114.15, 118.99, 122.22, 124.31, 124.38, 129.93, 130.51, 131.92, 132.27, 135.52, 140.32, 144.45, 148.57, 150.78, 151.36 (aromatic), 169.36 (CH3C=N); MS (m/z): 434 (M+); Anal. For C27H22N4S (434.56). (Calcd: C, 74.63; H, 5.10; N, 12.89%; Found: C, 74.61; H, 5.08; N, 12.93%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-(furan-2-yl)-4-(pyridin-3-yl)-1H-pyrrol-2-yl)aniline (3r)

M.p.=220-222ºC; IR (KBr, cm-1): 1183 (C-N), 1235 (C-O), 1536 (C=C), 1599 (C=N), 3099 (NH), 3245, 3298 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 4.92 (s, 1H, NH), 7.49-9.03 (m, 16H, Ar-H), 10.37 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 101.43, 107.52, 109.49, 112.43, 114.14, 118.58, 122.80, 124.31, 124.39, 126.27, 129.96, 130.53, 131.10, 132.29, 135.53, 140.34, 144.41, 148.57, 150.78, 151.37, 157.82 (aromatic), 169.35 (CH3C=N); MS (m/z): 418 (M+); Anal. For C27H22N4O (418.49). (Calcd: C, 77.49; H, 5.30; N, 13.39%; Found: C, 77.48; H, 5.33; N, 13.37%)

N-(1-(4-aminophenyl)ethylidene)-4-(4,5-di(pyridin-3-yl)-1H-pyrrol-2-yl)aniline (3s)

M.p.=210-212ºC; IR (KBr, cm-1): 1184 (C-N), 1538 (C=C), 1588 (C=N), 3098 (NH), 3245, 3299 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.43 (s, 1H, NH), 7.48-9.03 (m, 17H, Ar-H), 10.44 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 102.01, 109.23, 114.41, 118.60, 122.54, 124.30, 127.72, 129.93, 130.51, 131.10, 132.27, 135.52, 139.59, 146.79, 148.24, 150.60, 151.46 (aromatic), 169.36 (CH3C=N); MS (m/z): 429 (M+); Anal. For C28H23N5 (429.52). (Calcd: C, 78.30; H, 5.40; N, 16.31%; Found: C, 78.34; H, 5.37; N, 16.30%)

4-(5-(1H-indol-3-yl)-4-(pyridin-3-yl)-1H-pyrrol-2-yl)-N-(1-(4-aminophenyl)ethylidene)aniline (3t)

M.p.=180-181ºC; IR (KBr, cm-1): 1184 (C-N), 1537 (C=C), 1587 (C=N), 3102 (NH), 3244, 3296 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.50 (s, 1H, NH), 7.23-8.62 (m, 18H, Ar-H), 9.95 (s, 1H, NH), 10.42 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.52 (CH3C=N), 100.25, 109.49, 112.98, 115.32, 118.76, 120.76, 122.21, 123.73, 124.83, 126.86, 128.57, 129.75, 130.62, 131.78, 135.85, 138.99, 146.80, 148.82, 150.27, 151.44 (aromatic), 169.36 (CH3C=N); MS (m/z): 467 (M+); Anal. For C31H25N5 (467.56). (Calcd: C, 79.63; H, 5.39; N, 14.98%; Found: C, 79.66; H, 5.35; N, 14.99%)

4-(4-(1H-indol-3-yl)-5-phenyl-1H-pyrrol-2-yl)-N-(1-(4-aminophenyl)ethylidene)aniline (3u)

M.p.=150-152ºC; IR (KBr, cm-1): 1175 (C-N), 1529 (C=C), 1590 (C=N), 3112 (NH), 3182, 3259 (NH2); 1H NMR (DMSO-d6): δ=2.11 (s, 3H, CH3-C=N-), 5.24 (s, 1H, NH), 7.20-8.29 (m, 19H, Ar-H), 9.94 (s, 1H, NH), 10.32 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.26 (CH3C=N), 95.34, 108.36, 112.90, 114.15, 118.99, 121.28, 122.57, 123.91, 124.98, 129.93, 131.94, 134.66, 137.53, 138.96, 144.12, 150.60, 152.96 (aromatic), 169.66 (CH3C=N); MS (m/z): 466 (M+); Anal. For C32H26N4 (466.58). (Calcd: C, 82.38; H, 5.62; N, 12.01%; Found: C, 82.37; H, 5.60; N, 12.04%)

4-(4-(1H-indol-3-yl)-5-(thiophen-2-yl)-1H-pyrrol-2-yl)-N-(1-(4-aminophenyl)ethylidene)aniline (3v)

M.p.=138-140ºC; IR (KBr, cm-1): 1179 (C-N), 1316 (C-S), 1527 (C=C), 1590 (C=N), 3111 (NH), 3260, 3293 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.22 (s, 1H, NH), 7.20-8.63 (m, 17H, Ar-H), 9.94 (s, 1H, NH), 10.33 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.77 (CH3C=N), 95.32, 100.57, 107.19, 111.27, 112.92, 118.99, 121.28, 122.57, 123.90, 124.99, 129.94, 131.94, 135.84, 137.55, 139.00, 144.14, 150.60, 152.57 (aromatic), 169.09 (CH3C=N); MS (m/z): 472 (M+); Anal. For C30H24N4S (472.60). (Calcd: C, 76.24; H, 5.12; N, 11.85%; Found: C, 76.25; H, 5.13; N, 11.83%)

N-(1-(4-aminophenyl)ethylidene)-4-(5-(furan-2-yl)-4-(1H-indol-3-yl)-1H-pyrrol-2-yl)aniline (3w)

M.p.=150-152ºC; IR (KBr, cm-1): 1178 (C-N), 1262 (C-O), 1528 (C=C), 1590 (C=N), 3111 (NH), 3262, 3294 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.20 (s, 1H, NH), 7.20-8.57 (m, 17H, Ar-H), 9.94 (s, 1H, NH), 10.32 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.26 (CH3C=N), 95.33, 100.25, 106.08, 108.96, 112.91, 115.33, 118.99, 121.28, 122.58, 123.91, 124.58, 127.71, 129.94, 131.94, 137.54, 138.98, 144.13, 151.46, 153.75, 158.99 (aromatic), 169.09 (CH3C=N); MS (m/z): 456 (M+); Anal. For C30H24N4O (456.54). (Calcd: C, 78.92; H, 5.30; N, 12.27%; Found: C, 78.96; H, 5.28; N, 12.25%)

4-(4-(1H-indol-3-yl)-5-(pyridin-3-yl)-1H-pyrrol-2-yl)-N-(1-(4-aminophenyl)ethylidene)aniline (3x)

M.p.=162-164ºC; IR (KBr, cm-1): 1177 (C-N), 1531 (C=C), 1588 (C=N), 3111 (NH), 3260, 3309 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.50 (s, 1H, NH), 7.20-9.01 (m, 18H, Ar-H), 9.94 (s, 1H, NH), 10.35 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.53 (CH3C=N), 95.08, 99.40, 108.05, 112.93, 115.32, 118.60, 121.27, 122.56, 123.89, 124.59, 126.01, 128.31, 129.94, 131.93, 135.26, 137.57, 139.02, 147.39, 149.41, 150.01, 153.15 (aromatic), 169.35 (CH3C=N); MS (m/z): 467 (M+); Anal. For C31H25N5 (467.56). (Calcd: C, 79.63; H, 5.39; N, 14.98%; Found: C, 79.67; H, 5.36; N, 14.97%)

N-(1-(4-aminophenyl)ethylidene)-4-(4,5-di(1H-indol-3-yl)-1H-pyrrol-2-yl)aniline (3y)

M.p.=152-154ºC; IR (KBr, cm-1): 1179 (C-N), 1525 (C=C), 1589 (C=N), 3110 (NH), 3172, 3260 (NH2); 1H NMR (DMSO-d6): δ=2.09 (s, 3H, CH3-C=N-), 5.42 (s, 1H, NH), 7.20-8.63 (m, 19H, Ar-H), 10.11 (s, 1H, NH), 10.44 (s, 2H, NH2 D2O exchangeable); 13C NMR (DMSO-d6): δ 24.53 (CH3C=N), 11.54, 16.13, 101.69, 107.52, 109.48, 114.25, 118.22, 122.57, 123.98, 124.83, 126.61, 128.56, 130.07, 131.77, 137.55, 139.00, 150.27, 152.04 (aromatic), 169.35 (CH3C=N); MS (m/z): 505 (M+); Anal. For C34H27N5 (505.61). (Calcd: C, 80.77; H, 5.38; N, 13.85%; Found: C, 80.79; H, 5.39; N, 13.82%)

The MTT protocol

(1) The 96 well tissue culture plate was inoculated with 1 × 105 cells/ml (100 ul/well) and incubated at 37ºC for 24 hrs to develop a complete monolayer sheet.

(2) Growth medium was decanted from 96 well microtiter plates after confluent sheet of cells were formed, the cell monolayer was washed twice with wash media.

(3) Two-fold dilutions of tested sample were made in Roswell Park Memorial Institute (RPMI) medium (CAISSON RPMI 1640 Medium) with 2% serum (maintenance medium).

(4) 0.1 ml of each dilution was tested in different wells leaving 3 wells as control, receiving only maintenance medium.

(5) The plate was incubated at 37ºC and examined. Cells were checked for any physical signs of toxicity, e.g. partial or complete loss of the monolayer, rounding, shrinkage, or cell granulation.

(6) MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) solution was prepared (5 mg/ml in PBS (phosphate buffered saline)) (BIO BASIC CANADA INC).

(7) 25 ul MTT solution was added to each well. Place on a shaking table, 150 rpm for 5 minutes, to thoroughly mix the MTT into the media.

(8) Incubate (37ºC, 5% CO2) for 1-5 hrs to allow the MTT to be metabolized.

(9) Dump off the media. (Dry plate on paper towels to remove residue if necessary).

(10) Resuspend formazan (MTT metabolic product) in 200 ul DMSO. Place on a shaking table, 150 rpm for 5 min, to thoroughly mix the formazan into the solvent.

(11) Read optical density at 545 nm and subtract background at 620 nm. Optical density should be directly correlated with cell quantity.

Conclusion

Conclusively, polyarylpyrrole derivatives were synthesized from readily available starting materialsvia a facile and efficientone-potPaal-Knorr method under both traditional and microwave methods. Microwave reactions increased reaction rates, yields of pure products as well as eco-friendly advantagesMost of the newly synthesized compoundsshow good results on HepG2as anticancer

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