Effect of substituents on benzenesulfonyl motif of 4-phenyl-1-arylsulfonylimidazolidinones for their cytotoxicity

Examination of novel 4-aminoquinoline derivatives designed and synthesized by a hybrid pharmacophore approach to enhance their anticancer activities

In an attempt to develop effective and potentially safe anticancer agents, thirty-six 4-aminoquinoline derived sulfonyl analogs were designed and synthesized using a hybrid pharmacophore approach. The cytotoxicity of these compounds was determined using three breast tumor cell lines (MDA-MB231, MDA-MB468 and MCF7) and two matching non-cancer breast epithelial cell lines (184B5 and MCF10A). Although most of the compounds were quite effective on the breast cancer cells, the compound 7-chloro-4-(4-(2,4-dinitrophenylsulfonyl)piperazin-1-yl)quinoline (13; VR23) emerged as potentially the most desirable one in this series of compounds. Data from the NCI-60 cancer panel screening show that compound 13 is effective on a wide range of different cancers. Importantly, compound 13 is needed up to 17.6-fold less doses to achieve the same IC₅₀ against cancer than non-cancer cells (MDA-MB468 vs MCF10A), suggesting that it can potentially be less toxic to normal cells. Cancer cells formed multiple centrosomes in the presence of compound 13, resulting in the cell cycle arrest at prometa-meta phase. This abnormality leads to eventual cell demise with sub-G1 DNA content typically shown with apoptotic cells. In addition, compound 13 also causes an increase in lysosomal volume in cancer but not in non-cancer cells, which may contribute at least in part to its preferential cancer cell-killing. The cancer cell-killing effect of compound 13 is highly potentiated when combined with either bortezomib or monastrol.

Identification of N-arylsulfonylpyrimidones as anticancer agents

For confirming the role of five membered ring of imidazolidinone moiety of N-arylsulfonylimidazolidinones (7) previously reported with highly potent anticancer agent, a series of N-arylsulfonylpyrimidones (10a-g) and N-arylsulfonyltetrahydropyrimidones (11a-e) were prepared and their anti-proliferating activity was measured against human cancer cell lines (renal ACHN, colon HCT-15, breast MDA-MB-231, lung NCI-H23, stomach NUGC-3, and prostate PC-3) using XTT assay. Among them, 1-(1-acetylindolin-5-ylsulfonyl)-4-phenyltetrahydropyrimidin-2(1H)-one (11d, mean GI₅₀ = 3.50 µM) and ethyl 5-(2-oxo-4-phenyltetrahydropyrimidin-1(2H)-ylsulfonyl)-indoline-1-carboxylate (11e, mean GI₅₀ = 0.26 µM) showed best growth inhibitory activity against human cancer cell lines. Considering the activity results, N-arylsulfonyltetrahydropyrimidones (11) exhibited more potent activity compared to N-arylsulfonylpyrimidones (10) and comparable activity to N-arylsulfonylimidazolidinones (7). Especially, tetrahydropyrimidin-2(1H)-one analogs containing acylindolin-5-ylsulfonyl moiety at position 1 demonstrated their strong growth inhibitory activity against human cancer cell lines.

Synthesis and antiviral activity of 1-(1,3-disubstitutedimidazolidyn-2-ylidene)-3-ethoxycarbonylmethylurea derivatives

Novel 1-(1,3-disubstituted-imidazolidyn-2-ylidene)-3-ethoxycarbonylmethylurea derivatives (3a-3j) were obtained from appropriate 1-aryl-3-arylsulfonyl-1H-imidazolidine-2-imines (1a-1j) and ethyl isocyanatoacetate (2), which were subjected to condensation. Seven compounds were tested for their antiviral activity against HSV-1 and CVB3 viruses. Among the tested compounds, 3c was found to be active against HSV-1, proving that 4-methoxy substituent as R and 4-methyl substituent as R1 are most beneficial for activity against this virus. Furthermore, 3e and 3g were active against CVB3, which demonstrated that both 4-methyl and 4-chloro substitution is tolerated as R1, whereas 4-chloro and 2-methoxy substituents are best as R. It was also shown that the active compounds are characterized by relatively big surface area, small ovality, and greatest HOMO and LUMO energies in comparison to the rest of the compounds.

1-Acetyl-5-meth-oxy-4-(phenyl-sulfan-yl)imidazolidin-2-one

The title compound, C12H14N2O3S, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. The five-membered imidazolidin-2-one rings in both mol-ecules are twisted about the C-C bond. In the crystal, the A and B mol-ecules are associated via pairs of N-H⋯O hydrogen bonds, forming A-B dimers. These dimers are linked via C-H⋯S hydrogen bonds, forming double dimers, which are in turn linked via C-H⋯O hydrogen bonds forming two-dimensional networks lying parallel to (001). There are also C-H⋯π inter-actions present, which consolide the layers and link them, so forming a three-dimensional structure.

Synthesis and Conformational Analysis of Sterically Congested (4R)-(−)-1-(2,4,6-Trimethylbenzenesulfonyl)-3-n-butyryl-4-tert-butyl-2-imidazolidinone: X-Ray Crystallography and Semiempirical Calculations

The crystal structure of (4R)-(−)-1-(2,4,6-trimethylbenzenesulfonyl)-3-n-butyryl-4-tert-butyl-2-imidazolidinone(3)was determined by single-crystal X-ray diffraction. Compound3crystallizes in triclinic system in space groupP1 (≠1). The crystal data area=10.62165 Å,b=16.5321 Å,c=8.95729 Å,∝=91.1936∘,β=93.8496∘,γ=88.0974∘,V=1568.22 Å3,Z=3,Dcalc=1.253 g/cm3,μCuKα=15.98 cm−1,F000=636.00,T=20.0°C, andR=0.037. The crystal structure confirmed the occurrence of three molecules of3A,3B, and3Cin which then-butyryl moiety adopted thes-transoidconformation. Crystal structure also revealed that the conformation of 2,4,6-trimethylbenzenesulfonyl groups was inanti-position relative totert-butyl group. The crystal packing showed that three molecules of compound3are stacked as a result of intermolecularπ-πinteractions between the phenyl ring of one molecule and the phenyl ring of the other molecule by approaching each other to an interplanar separation of 5.034 Å. Interestingly, these stacked molecules are also connected by intermolecularCH-πinteraction. The conformational analysis of thes-transoid  3A,3B, and3Cwas separately performed by molecular mechanic MM+ force field. Additionally, computational investigation using semiempirical AM1 and PM3 methods was performed to find a correlation between experimental and calculated geometrical parameters. The data obtained suggest that the structural data furnished by the AM1 method is in better agreement with those experimentally determined for the above compound. It has been found that the lowest energetic conformer computed gives approximate correspondence with experimental solid state data.

Design, synthesis, single-crystal and preliminary antitumor activity of novel arenesulfonylimidazolidin-2-ones

Novel series of 1-(arenesulfonyl)imidazolidin-2-one (3a-i) and 1,3-bis(arenesulfonyl)imidazolidin-2-one (5a-i) have been synthesized and tested for their antitumor activity against 60 tumor cell lines taken from nine different organs. A significant inhibition for cancer cells was observed with series 5a-i compounds compared with the series 3a-i which showed a weak inhibition. Compounds 5a-i showed good inhibitory effect at the lung cancer HOP-92 and renal cancer CAKI-1 and UO-31 cell lines. Compound 5e showed remarkable broad-spectrum antitumor activity.

Evaluation of anticancer activity of 4-vinyl-1-arylsulfonylimidazolidinones

To continue exploration of structure activity relationship of novel 1-(indoline-5-sulfonyl)-4-phenylimidazolidinones (1) reported as anticancer agent with broad spectrum, three 1-(arylsulfonyl)-4-vinylimidazolidinones (2) were synthesized from methyl serinate (3) in 8 steps. Reaction of intermediate 2-phenoxycarbonylaminobut-3-enyl p-toluenesulfonate (10) with arylsulfonamide in the presence of potassium carbonate produced corresponding 2 and N-(4-vinyloxazolidin-2-yl)arylsulfonamide 11 in approximately equal ratio. This reaction is believed to undergo through urea intermediate 16 as shown in scheme 3. 1-Arylsufonyl-4-vinylimidazolidinones 2 show much reduced activity against human colon carcinoma (Colo205), human chronic myelogenous leukemia (K562), and human ovarian adenocarcinoma (SK-OV-3) and compatible activity against human lung carcinoma (A549) compared to 1. Therefore phenyl at 4-position should be the optimum planar motif for the activity of 1.

Synthesis and cytotoxic activity of 1-(1-benzoylindoline-5-sulfonyl)-4-phenylimidazolidinones

The novel 1-(1-benzoylindoline-5-sulfonyl)-4-phenyl-4,5-dihydroimidazolones 2 shows highly potent and broad cytotoxicities. Their cytotoxicities against human lung carcinoma A549, human chronic myelogenous leukemia K562, and human ovarian adenocarcinoma SK-OV-3 are compatible with doxorubicin. Compound 2p (1-[(4-aminobenzoyl)indoline-5-sulfonyl])-4-phenyl-4,5-dihydroimidazolone) exhibits a cytotoxicity that is far more potent than doxorubicin and also exhibits highly effective antitumour activities against murine (3LL, Colon 26) and human xenograft (NCI-H23, SW620) tumor models.

The 3D-QSAR study of antitumor arylsulfonylimidazolidinone derivatives by CoMFA and CoMSIA

Three-dimensional quantitative structure-activity relationship (3D-QSAR) studies for a series of arylsulfonylimidazolidinone derivatives having antitumor activity were conducted using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The in vitro cytotoxicity against human lung carcinoma (A549) exhibited a strong correlation with steric and electrostatic factors of the molecules. Four different types of models have been built using CoMFA and CoMSIA method with AM1 charge or Gasteiger-Huckel charge. By comparison of the statistical results of these models, model I obtained by CoMFA study with AM1 showed the best predictability of the antitumor activities based on the cross-validated value (0.642), conventional r2 (0.981), standard error of estimate (0.106) and PRESS value (0.170).

Importance of sulfonylimidazolidinone motif of 4-phenyl-1-arylsulfonylimidazolidinones for their cytotoxicity: synthesis of 2-benzoyl-4-phenyl[1,2,5]thiazolidine-1,1-dioxides and their cytotoxcity

For probing the importance of planarity of imidazolidinone motif of 4-phenyl-1-(benzenesulfonyl)imidazolidinones 1 for their cytotoxicity, 4-phenyl-2-(benzoyl)[1,2,5]thiadiazolidine-1,1-dioxide (2a), 4-phenyl-2-(p-toluoyl)[1,2,5]thiadiazolidine-1,1-dioxide (2b), 4-phenyl-2-(phenylcarbamoyl)[1,2,5]thiadiazolidine-1,1-dioxide (3a), and 4-phenyl-2-(p-tolylcarbamoyl)[1,2,5]thiadiazolidine-1,1-dioxide (3b) were prepared along with their regioisomers (5a, 5b, 9a, 9b) and their cytotoxicity were measured against human lung carcinoma (A549), human colon carcinoma (COL0205), human ovarian cancer (SK-OV-3), human leukemic cancer (K562), and murine colon adenocarcinoma (Colon26) cell lines in vitro. All compounds prepared do not show any activity against all five cancer cell lines unlike 1. Compounds 1 possess planarity of imidazolidinone, especially in sulfonylurea moiety (-SO2NHCONH-). However compounds 2 and 3 have nonplanar 5-membered ring, [1,2,5]thiadiazolidine-1,1-dioxides. Such structural differentiation might result in the loss of activity. Therefore the inactivity of 2 and 3 could also be an indication for the necessity of planarity of imidazolidinone ring of 1 for their cytotoxic activity.

Recognition of the importance of imidazolidinone motif for cytotoxicity of 4-phenyl-1-arylsulfonylimidazolidinones using thiadiazolidine-1,1-dioxide analogs

For probing the importance of planarity of imidazolidinone motif of 4-phenyl-1-(N-acylindoline-5-sulfonyl)imidazolidinones for their cytotoxicity, 4-phenyl-1-(N-acylindoline-5-sulfonyl)[1,2,5]thiadiazolidine-1,1-dioxides 2 were prepared and their cytotoxicity were measured against human lung carcinoma (A549), human colon carcinoma (COL0205), human ovarian cancer (SK-OV-3), human leukemic cancer (K562), and murine colon adenocarcinoma (Colon26) cell lines in vitro. Although only carbonyl moiety of imidazolidinone ring was replaced with sulfonyl group, compounds 2 do not show any activity against all five cancer cell lines unlike 1. Therefore the planarity of imidazolidinone ring of 1 should be an important factor for their cytotoxic activity.

Evaluation of the role of imidazolidinone motif of antineoplastic 4-phenyl-1-arylsulfonylimidazolidinones using 4-phenyl-2-arylsulfonyloxazolines

To evaluate the role of imidazolidinone moiety of potential anticancer 4-phenyl-1-arylsulfonylimidazolidinones 1 for their cytotoxicity, conformationally similar 4-phenyl-2-arylsulfonylaminooxazolines 2 were synthesized and compared their cytotoxicities with those of the corresponding 1. Compounds 2 showed much reduced activity compared to N-arylsulfo-nylimidazolidinones 1. This result might indicate that the imidazolidinone ring of 1 have the other roles for the activity as an essential structural motif in addition to conformational contribution.