Recent synthetic strategies of spiro-azetidin-2-one, -pyrrolidine, -indol(one) and -pyran derivatives-a review.

Spiro-heterocycles have received special attention in medicinal chemistry because of their promising biological activity. Over the years, many synthetic methodologies have been established for the construction of spirocyclic compounds. Spiro heterocycles such as spiro-azetidin-2-one, -pyrrolidine, -indol(one) and -pyran derivatives have been found to exhibit diversified biological and pharmacological activity in addition to their therapeutic properties. In view of these facts, we decided in this review to present representative synthetic approaches of the aforementioned spiro heterocycles, especially in the past 20 years.

Novel quinoline/thiazinan-4-one hybrids; design, synthesis, and molecular docking studies as potential anti-bacterial candidates against MRSA.

In an attempt to develop effective and safe antibacterial agents, we synthesized novel thiazinanones by combining the quinolone scaffold and the 1,3-thiazinan-4-one group by reaction between ((4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)methylene)hydrazinecarbothioamides and 2,3-diphenylcycloprop-2-enone in refluxing ethanol in the presence of triethyl amine as a catalyst. The structure of the synthesized compounds was characterized by spectral data and elemental analysis, IR, MS, 1H and 13C NMR spectroscopy which showed two doublet signals for CH-5 and CH-6 and four sharp singlets for the protons of thiazinane NH, CH[double bond, length as m-dash]N, quinolone NH and OH, respectively. Also, the 13C NMR spectrum clearly showed the presence of two quaternary carbon atoms which were assigned to thiazinanone-C-5 and C-6. All the 1,3-thiazinan-4-one/quinolone hybrids were screened for antibacterial activity. Compounds 7a, 7e and 7g showed broad spectrum antibacterial activity against most of the tested strains either G +ve or G -ve. Compound 7e is the most potent antibacterial agent against MRSA with the minimum inhibitory concentration against MRSA found to be 48 µg mL-1 compared to the drug ciprofloxacin (96 µg mL-1). Additionally, a molecular docking study was performed to understand the molecular interaction and binding mode of the compounds on the active site of S. aureus Murb protein. In silico docking assisted data strongly correlated with the experimental approach of antibacterial activity against MRSA.

Design and synthesis of new thiazolidinone/uracil derivatives as antiproliferative agents targeting EGFR and/or BRAFV600E.

Thiourea derivatives of uracil were efficiently synthesized via the reaction of 5-aminouracil with isothiocyanates. Then, we prepared uracil-containing thiazoles via condensation of thioureas with diethyl/dimethyl acetylenedicarboxylates. The structures of the products were confirmed by a combination of spectral techniques including infra-red (IR), nuclear magnetic resonance (NMR), mass spectrometry (MS) and elemental analyses. A rationale for the formation of the products is presented. The newly synthesized compounds were evaluated for their in vitro antiproliferative activity against four cancer cell lines. The compounds tested showed promising antiproliferative activity, with GI50 values ranging from 1.10 µM to 10.00 µM. Compounds 3c, 5b, 5c, 5h, 5i, and 5j were the most potent derivatives, with GI50 values ranging from 1.10 µM to 1.80 µM. Compound 5b showed potent inhibitory activity against EGFR and BRAFV600E with IC50 of 91 ± 07 and 93 ± 08 nM, respectively, indicating that this compound could serve as a dual inhibitor of EGFR and BRAFV600E with promising antiproliferative properties. Docking computations revealed the great potency of compounds 5b and 5j towards EGFR and BRAFV600E with docking scores of -8.3 and -9.7 kcal/mol and -8.2 and -9.3 kcal/mol, respectively.

Design, Synthesis and Biological Evaluation of Syn and Anti-like Double Warhead Quinolinones Bearing Dihydroxy Naphthalene Moiety as Epidermal Growth Factor Receptor Inhibitors with Potential Apoptotic Antiproliferative Action.

Our investigation includes the synthesis of new naphthalene-bis-triazole-bis-quinolin-2(1H)-ones 4a−e and 7a−e via Cu-catalyzed [3 + 2] cycloadditions of 4-azidoquinolin-2(1H)-ones 3a−e with 1,5-/or 1,8-bis(prop-2-yn-1-yloxy)naphthalene (2) or (6). All structures of the obtained products have been confirmed with different spectroscopic analyses. Additionally, a mild and versatile method based on copper-catalyzed [3 + 2] cycloaddition (Meldal−Sharpless reaction) was developed to tether quinolinones to O-atoms of 1,5- or 1,8-dinaphthols. The triazolo linkers could be considered as anti and syn products, which are interesting precursors for functionalized epidermal growth factor receptor (EGFR) inhibitors with potential apoptotic antiproliferative action. The antiproliferative activities of the 4a−e and 7a−e were evaluated. Compounds 4a−e and 7a−e demonstrated strong antiproliferative activity against the four tested cancer cell lines, with mean GI50 ranging from 34 nM to 134 nM compared to the reference erlotinib, which had a GI50 of 33 nM. The most potent derivatives as antiproliferative agents, compounds 4a, 4b, and 7d, were investigated for their efficacy as EGFR inhibitors, with IC50 values ranging from 64 nM to 97 nM. Compounds 4a, 4b, and 7d demonstrated potent apoptotic effects via their effects on caspases 3, 8, 9, Cytochrome C, Bax, and Bcl2. Finally, docking studies show the relevance of the free amino group of the quinoline moiety for antiproliferative action via hydrogen bond formation with essential amino acids.

Species-Based Differences in Mechanical Properties, Cytocompatibility, and Printability of Methacrylated Collagen Hydrogels.

Collagen methacrylation is a promising approach to generate photo-cross-linkable cell-laden hydrogels with improved mechanical properties. However, the impact of species-based variations in amino acid composition and collagen isolation method on methacrylation degree (MD) and its subsequent effects on the physical properties of methacrylated collagen (CMA) hydrogels and cell response are unknown. Herein, we compared the effects of three collagen species (bovine, human, and rat), two collagen extraction methods (pepsin digestion and acid extraction), and two photoinitiators (lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) and Irgacure-2959 (I-2959)) on the physical properties of CMA hydrogels, printability and mesenchymal stem cell (MSC) response. Human collagen showed the highest MD. LAP was more cytocompatible than I-2959. The compressive modulus and cell viability of rat CMA were significantly higher (p < 0.05) than bovine CMA. Human CMA yielded constructs with superior print fidelity. Together, these results suggest that careful selection of collagen source and cross-linking conditions is essential for biomimetic design of CMA hydrogels for tissue engineering applications.

Synthesis and Identification of New N,N-Disubstituted Thiourea, and Thiazolidinone Scaffolds Based on Quinolone Moiety as Urease Inhibitor.

Synthesis of thiazolidinone based on quinolone moiety was established starting from 4-hydroxyquinol-2-ones. The strategy started with the reaction of ethyl bromoacetate with 4-hydroxyquinoline to give the corresponding ethyl oxoquinolinyl acetates, which reacted with hydrazine hydrate to afford the hydrazide derivatives. Subsequently, hydrazides reacted with isothiocyanate derivatives to give the corresponding N,N-disubstituted thioureas. Finally, on subjecting the N,N-disubstituted thioureas with dialkyl acetylenedicarboxylates, cyclization occurred, and thiazolidinone derivatives were obtained in good yields. The two series based on quinolone moiety, one containing N,N-disubstituted thioureas and the other containing thiazolidinone functionalities, were screened for their in vitro urease inhibition properties using thiourea and acetohydroxamic acid as standard inhibitors. The inhibition values of the synthesized thioureas and thiazolidinones exhibited moderate to good inhibitory effects. The structure-activity relationship revealed that N-methyl quinolonyl moiety exhibited a superior effect, since it was proved to be the most potent inhibitor in the present series achieving (IC50 = 1.83 ± 0.79 µM). The previous compound exhibited relatively much greater activity, being approximately 12-fold more potent than thiourea and acetohydroxamic acid as references. Molecular docking analysis showed a good protein-ligand interaction profile against the urease target (PDBID: 4UBP), emphasizing the electronic and geometric effect of N,N-disubstituted thiourea.

A review on the synthesis of heteroannulated quinolones and their biological activities.

The quinoline scaffold has become an important construction motif for the development of new drugs. The quinolones and their heteroannulated derivatives have high importance due to their diverse spectrum of biological activities as antifungal, anti-inflammatory, anti-diabetes, anti-Alzheimer's disease, antioxidant and diuretic activities. This review summarizes the various new, efficient and convenient synthetic approaches to synthesize diverse quinolone-based scaffolds and their biological activities. We also dealt with the important mechanism, the route and type of reactions of the obtained products. The biological activities of some heteroannulated quinolones were also discussed.

Design and Synthesis of (2-oxo-1,2-Dihydroquinolin-4-yl)-1,2,3-triazole Derivatives via Click Reaction: Potential Apoptotic Antiproliferative Agents.

A mild and versatile method based on Cu-catalyzed [2+3] cycloaddition (Huisgen-Meldal-Sharpless reaction) was developed to tether 3,3'-((4-(prop-2-yn-1-yloxy)phenyl)methylene)bis(4-hydroxyquinolin-2(1H)-ones) with 4-azido-2-quinolones in good yields. This methodology allowed attaching three quinolone molecules via a triazole linker with the proposed mechanism. The products are interesting precursors for their anti-proliferative activity. Compound 8g was the most active one, achieving IC50 = 1.2 ± 0.2 µM and 1.4 ± 0.2 µM against MCF-7 and Panc-1 cell lines, respectively. Moreover, cell cycle analysis of cells MCF-7 treated with 8g showed cell cycle arrest at the G2/M phase (supported by Caspase-3,8,9, Cytochrome C, BAX, and Bcl-2 studies). Additionally, significant pro-apoptotic activity is indicated by annexin V-FITC staining.

Development of 2'-aminospiro [pyrano[3,2-c]quinoline]-3'-carbonitrile derivatives as non-ATP competitive Src kinase inhibitors that suppress breast cancer cell migration and proliferation.

Src kinase activity controls diverse cellular functions, including cell growth, migration, adhesion, and survival. It is de-regulated in several cancers, including breast cancer, where it is highly expressed and phosphorylated. Thus, targeting Src by a small molecule is a feasible strategy for managing different breast cancer types. Several Src kinase inhibitors are available, including the FDA-approved drug (dasatinib). However, they are primarily ATP-competitive inhibitors that have been reported to lack specificity towards Src. We have a long-time interest in discovering protein kinase inhibitors that are non-competitive for ATP. In this project, three groups of 2'-aminospiro[pyrano[3,2-c]quinoline]-3'-carbonitrile derivatives were designed and synthesized, hypothesizing that small molecules with a spiro scaffold appended to a pyrano[3,2-c]quinoline analog could act as non-ATP competitive Src kinase inhibitors. 3b, 3c, and 3d inhibited Src kinase activity with IC50s of 4.9, 5.9, and 0.9 µM, respectively. At the same time, they did not impact the MDM2/p53 interaction in HEK293 cells, which has been reported to be affected by some spirocyclic compounds. 25 µM of 3b, 3c, or 3d did not inhibit the kinase activity of ERK2, JNK1, or p38-alpha in an in-vitro kinase assay. Steady-state kinetic studies for the effect of 3d on the ability of recombinant Src to phosphorylate its substrate (Srctide) revealed a non-ATP competitive inhibition mechanism. 1.6 µM of 3d was enough to diminish Src, Fak, and paxillin phosphorylation in the breast cancer cell lines MDA-MB-231 and MCF7. In the NCI screening, 3d induced broad tumor cytotoxicity for the NCI-60 cell lines, including all the breast cancer cell lines. The potency of 3b, 3c, and 3d to inhibit migration, proliferation, and colony formation of MDA-MB-231 and proliferation of MCF7 cells correlates with their potency to suppress Src kinase activity in the same cell line. Noticeably, the cell growth suppression and apoptosis induction in the tested cell lines can be attributed to the ability of the new derivatives to suppress the ERK and Akt survival pathways downstream of Src.

Identification and molecular modeling of new quinolin-2-one thiosemicarbazide scaffold with antimicrobial urease inhibitory activity.

A new series of 6-substituted quinolin-2-one thiosemicarbazides 6a-j has been synthesized. The structure of the target compounds was proved by different spectroscopic and elemental analyses. All the designed final compounds were evaluated for their in vitro activity against the urease-producing R. mucilaginosa and Proteus mirabilis bacteria as fungal and bacterial pathogens, respectively. Moreover, all compounds were in vitro tested as potential urease inhibitors using the cup-plate diffusion method. Compounds 6a and 6b were the most active with (IC50 = 0.58 ± 0.15 and 0.43 ± 0.09 µM), respectively, in comparison with lead compound I (IC50 = 1.13 ± 0.00 µM). Also, the designed compounds were docked into urease proteins (ID: 3LA4 and ID: 4UBP) using Open Eye® software to understand correctly about ligand-receptor interactions. The docking results revealed that the designed compounds can interact with the active site of the enzyme through multiple strong hydrogen bonds. Moreover, rapid overlay of chemical structures' analysis was described to understand the 3D QSAR of synthesized compounds as urease inhibitors. The results emphasize the importance of polar thiosemicarbazide directly linked to 6-substituted quinolone moieties as promising antimicrobial urease inhibitors.

ß-Cyclodextrin Encapsulation of Synthetic AHLs: Drug Delivery Implications and Quorum-Quenching Exploits.

Many bacteria, such as Pseudomonas aeruginosa, regulate phenotypic switching in a population density-dependent manner through a phenomenon known as quorum sensing (QS). For Gram-negative bacteria, QS relies on the synthesis, transmission, and perception of low-molecular-weight signal molecules that are predominantly N-acyl-l-homoserine lactones (AHLs). Efforts to disrupt AHL-mediated QS have largely focused on the development of synthetic AHL analogues (SAHLAs) that are structurally similar to native AHLs. However, like AHLs, these molecules tend to be hydrophobic and are poorly soluble under aqueous conditions. Water-soluble macrocycles, such as cyclodextrins (CDs), that encapsulate hydrophobic guests have long been used by both the agricultural and pharmaceutical industries to overcome the solubility issues associated with hydrophobic compounds of interest. Conveniently, CDs have also demonstrated anti-AHL-mediated QS effects. Here, using fluorescence spectroscopy, NMR spectrometry, and mass spectrometry, we evaluate the affinity of SAHLAs, as well as their hydrolysis products, for ß-CD inclusion. We also evaluated the ability of these complexes to inhibit wild-type P. aeruginosa virulence in a Caenorhabditis elegans host infection study, for the first time. Our efforts confirm the potential of ß-CDs for the improved delivery of SAHLAs at the host/microbial interface, expanding the utility of this approach as a strategy for probing and controlling QS.

Design, Synthesis, Molecular Docking, Antiapoptotic and Caspase-3 Inhibition of New 1,2,3-Triazole/Bis-2(1H)-Quinolinone Hybrids.

A series of novel 1,2,3-triazoles hybridized with two quinolin-2-ones, was designed and synthesized through click reactions. The structures of the synthesized compounds were elucidated by NMR, IR, and mass spectra in addition to elemental analysis. The synthesized compounds were assessed for their antiapoptotic activity in testis, as testicular torsion is the main cause of male infertility. This effect was studied in light of decreasing tissue damage induced by I/R in the testis of rats using N-acetylcysteine (NAC) as an antiapoptotic reference. Compounds 6a-c were the most active antiapoptotic hybrids with significant measurements for malondialdehyde (MDA) and total antioxidant capacity (TAC) and the apoptotic biomarkers (testicular testosterone, TNFα, and caspase-3) in comparison to the reference. A preliminary mechanistic study was performed to improve the antiapoptotic activity through caspase-3 inhibition. A compound assigned as 6-methoxy-4-(4-(((2-oxo-1,2-dihydroquinolin-4-yl)oxy)methyl)-1H-1,2,3-triazol-1-yl)quinolin-2(1H)-one (6c) was selected as a representative of the most active hybrids in comparison to NAC. Assay of cytochrome C for 6c revealed an attenuation of cytochrome C level about 3.54 fold, comparable to NAC (4.13 fold). In caspases-3,8,9 assays, 6c was found to exhibit more potency and selectivity toward caspase-3 than other caspases. The testicular histopathological investigation was carried out on all targeted compounds 6a-g, indicating a significant improvement in the spermatogenesis process for compounds 6a-c if compared to the reference relative to the control. Finally, molecular docking studies were done at the caspase-3 active site to suggest possible binding modes. Hence, it could conceivably be hypothesized that compounds 6a-c could be considered good lead candidate compounds as antiapoptotic agents.

Design and synthesis of new pyranoquinolinone heteroannulated to triazolopyrimidine of potential apoptotic antiproliferative activity.

Pyrano[3,2-c]quinoline derivatives have been synthesized and utilized to obtain various new hetero-annulated triazolopyrimidine, containing quinoline, pyran, 1,2,4-triazine and pyrimidine in good yields. Newly synthesized compounds have been characterized by spectral data and elemental analysis. Most of the synthesized compounds showed moderate to weak antiproliferative activity on most cancer cell lines, especially leukemia and breast cancer cell lines. The open chain formimidic acid ethyl ester is slightly more potent than hetero-annulated systems. The most active compounds were further investigated for caspase activation, Bax activation and Bcl-2 down regulation compared to doxorubicin as a standard, and indeed exhibited mainly cell cycle arrest at the Pre-G1 and G2/M phases. The transcription effects of 5a and 5b on the p53 were assessed and compared with the reference doxorubicin. The results revealed an increase of 12-19 in p53 level compared to the test cells and that p53 protein level of 5a and 5b was significantly inductive (991, and 639 pg/mL, respectively) in relation to doxorubicin (1263 pg/mL).

New quinoline-2-one/pyrazole derivatives; design, synthesis, molecular docking, anti-apoptotic evaluation, and caspase-3 inhibition assay.

We report the synthesis of new quinoline-2-one/pyrazole hybrids and their antiapoptotic activity. This effect was studied in sight of decreasing tissue damage induced by I/R in colon of rats using N-acetylcysteine (NAC) as anti-apoptotic reference. Compounds 6a, 6c and 6f showed significant improvement for oxidative stress parameters MDA, SOD, GSH and NOx in comparison with model group and greater than the reference NAC (N-acetylcysteine), whereas compounds 6d and 6e exhibited weaker antioxidant activity when compared with the reference NAC. Moreover, compounds 6a, 6c and 6f showed significant decrease in inflammatory mediators TNFα and CRB greater than NAC when compared to the model group especially compound 6c whose found CRB conc 1.90 (mg/dL) in comparison to NAC of conc 2.13 mg/dL. Additionally, colonic histopathological investigation was performed to all targeted compounds that indicates H&E sections of compounds 6a and 6f revealed apparent normal colonic cells while compound 6e showed dilated blood vessels with more apoptotic cells if compared with NAC. Caspase-3 inhibition assay revealed that compounds 6a, 6b and 6d weaken caspase-3 expression to an extent higher than NAC (1.063, 0.430, 0.731 and 1.115, respectively). Docking studies with caspase-3 revealed that most of the tested compounds showed good binding with the enzyme especially for compound 6d make several interactions better than that of the reference NAC.

Synthesis of New Fused Heterocyclic 2-Quinolones and 3-Alkanonyl-4-Hydroxy-2-Quinolones.

Herein, we report the synthesis of 5,12-dihydropyrazino[2,3-c:5,6-c']difuro[2,3-c:4,5-c']-diquinoline-6,14(5H,12H)diones, 2-(4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-1,4-diphenyl- butane-1,4-diones and 4-(benzo-[d]oxazol-2-yl)-3-hydroxy-1H-[4,5]oxazolo[3,2-a]pyridine-1-one. The new candidates were synthesized and identified by different spectroscopic techniques, and X-ray crystallography.

Functionalized 1,3-Thiazolidin-4-Ones from 2-Oxo-Acenaphthoquinylidene- and [2.2]Paracyclophanylidene-Thiosemicarbazones.

The reactions of dialkyl acetylenedicarboxylates with various 2-oxo-acenaphthoquinylidene- and 4-acetyl[2.2]paracyclophanylidene-thiosemicarbazones were investigated. Using simple experimental procedures, 1,3-Thiazolidin-4-ones derived from acenaphthequinone or [2.2]paracyclophane were obtained as major products in good yields. In the case of allyl derivative of acenaphthoquinylidene-thiosemicarbazones, a complex structure of tetramethyl 5-(2-(((Z,E)-N-allyl-N'-(2-oxoacenaphthylen-1(2H)-ylidene)carbamohydrazonoyl)thio)-1,2,3-tris-(methoxycarbonyl)-cyclopropyl)-4-methoxy-7-oxabicyclo[2.2.1]hepta-2,5-diene-1,2,3,6-tetracarboxylate was formed. Single crystal X-ray analysis was used as an efficient tool to confirm the structure of the synthesized compounds as well as different spectroscopic data (1H-NMR, 13C-NMR, 2D-NMR, mass spectrometry and elemental analysis). The mechanism of the obtained products was discussed.

Novel Pyrazoloquinolin-2-ones: Design, synthesis, docking studies, and biological evaluation as antiproliferative EGFR-TK inhibitors.

Two new series of diethyl 2-[2-(substituted-2-oxo-1,2-dihydroquinolin-4-yl)hydrazono]-succinates 6a-g and 1-(2-oxo-1,2-dihydroquinolin-4-yl)-1H-pyrazoles 7a-f have been designed and synthesized. The structures of the synthesized compounds were proved by IR, mass, NMR (2D) spectra and elemental analyses. The target compounds were evaluated for their in vitro cytotoxic activity against 60 cancer cell lines according to NCI protocol. Consequently, seven compounds were further examined against the most sensitive cell lines, leukemia CCRF-CEM, and MOLT-4. 5-Amino-1-(6-bromo-2-oxo-1,2-dihydroquinolin-4-yl)-1H-pyrazole-3,4-dicarbonitrile (7f) was the most active product, with IC50 = 1.35 uM and 2.42 uM against MOLT-4 and CCRF-CEM, respectively. Also, it showed a remarkable inhibitory activity compared to erlotinib on the EGFR TK with IC50 = 247.14 nM and 208.42 nM, respectively. Cell cycle analysis of MOLT-4 cells treated with 7f showed cell cycle arrest at G2/M phase (supported by Caspases, BAX and Bcl-2 studies) with a significant pro-apoptotic activity as indicated by annexin V-FITC staining. Moreover, the docking study indicated that both the pyrazole moiety and the quinolin-2-one ring showed good fitting into EGFR (PDB code: 1M17). In order to interpret SAR of the designed compounds, and provide a basis for further optimization, molecular docking of the synthesized compounds to known EGFR inhibitors was performed. The study illustrated the effect of several factors on the compounds' activity.

Regioselective formation of 1,2,4-triazoles by the reaction of amidrazones in the presence of diethyl azodicarboxylate and catalyzed by triethylamine.

A general method for the synthesis of 1,3,5-trisubstituted 1,2,4-triazoles has been developed from reaction of amidrazones with ethyl azodicarboxylate and triethylamine (Mitsunobu reagent) in EtOH. This highly regioselective one-pot process provides rapid access to highly diverse triazoles. The reaction was explained, based on Mitsunobu reagent oxidizing ethanol to acetaldehyde, which would then react with amidrazones to give the substituted 3-methyltriazoles. A [2 + 3] cycloaddition reaction between two oxidized forms of amidrazones produced the second type of triazoles. X-ray structure analyses proved the structure of each type of product.

Synthesis of novel 1,2-bis-quinolinyl-1,4-naphthoquinones: ERK2 inhibition, cytotoxicity and molecular docking studies.

Two novel series of N-2,3-bis(6-substituted-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)naphthalene-1,4-diones 3a-d and substituted N-(methyl/ethyl)bisquinolinone triethyl-ammonium salts 4e,f were successfully synthesized. The synthesized compounds were targeted as new candidates to extracellular signal-regulated kinases 1/2 (ERK1/2) with considerable antineoplastic activity. The synthesis involved the reactions of 2 equivalents of 4-hydroxy-2(1H)-quinolinones 1a-f and one equivalent of 1,4-naphthoquinone (2) in a mixture of ethanol/dimethylformamide (1:1) as a solvent and 0.5 mL Et3N. In the reaction of 6-methyl-4-hydroxyquinolone 1b with 2, a side product 4b of the second series was obtained. In general, the presence of free NH-quinolone gave a single compound of the first series, whereas reaction of N-methyl/ethyl-quinolones 1e,f with 2 enhanced the formation of compounds of the second series. The structures of the new compounds were proved by different spectroscopic techniques such as IR, NMR (2D-NMR) and mass spectra, elemental analysis, and X-ray crystallography. To further elucidate the mechanism of action of these newly synthesized compounds, compounds 3a, 3b, 4e and 4f were selected to investigate for their MAP Kinases pathway inhibition together with molecular docking using ATP-binding site of ERK2. The results revealed that compounds 3a, 3b and 4f inhibited ETS-1 phosphorylation by ERK2 in a dose dependent manner. Also, compound 4f showed highest potency for ERK2 inhibition with ATP-competitive inhibition mechanism which was confirmed by the formation of three hydrogen bond in the molecular docking studies. The synthesized compounds were then tested for their in vitro anticancer activity against the NCI-60 panel of tumor cell lines. Interestingly, the selected compounds displayed from modest to strong cytotoxic activities. Compound 3b demonstrated broad spectrum anti-tumor activity against the nine tumor sub-panels tested, while compound 3d proved to be lethal to most of the cancer cell lines as shown by their promising GI50 and TGI values in NCI in vitro five dose testing. These results revealed that the synthesized compounds can potentially serve as leads for the development of novel chemotherapeutic agents and structure improvement will be necessary for some derivatives for enhancing their cellular activities and pharmacokinetic profile.

Thieno[2,3-d]pyrimidines in the synthesis of antitumor and antioxidant agents.

Dimethyl acetylenedicarboxylate, ethyl propiolate, and E-dibenzoylethylene react with thienopyrimidines (cyclo-pentyl, -hexyl, and -heptyl) derivatives to form thiazolo[3,2-a]thieno-[2,3-d]pyrimidin-2-ylidene) acetates, thieno[2,3-d]pyrimidin-2-ylthioacrylates, and thieno[2',3':4,5]pyrimido[2,1-b][1,3]thiazin-6-ones, respectively. Reactions proceed via cyclization and thio-addition processes. Some derivatives of thienopyrimidines showed high inhibition of Hep-G2 cell growth compared with the growth of untreated control cells. However, the fused heptyl of thienopyrimidothiazines indicates a promising specific antitumor agent against Hep-G2 cells with IC(50 )< 20 microM.