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New imidazo[2,1-b]thiazole analogs were designed, synthesized, and biologically evaluated as anticancer agents. In vitro biological evaluation of the anticancer properties of the compounds was performed against different cancer cell lines. Compounds 23 and 39 showed remarkable broad -spectrum cytotoxic potency on most of the tested cell lines. Compounds 23 and 39 exhibited potent activity against the MCF-7 breast cancer cell line, with IC 50 values of 1.81 and 4.95 μM, respectively, compared to DOX and SOR (IC 50 values of 4.17 and 7.26 μM, respectively). An enzyme inhibition assay was carried out to clarify the possible mode of action of the tested compounds. Compounds 23 and 39 were identified as possible EGFR, HER-2, and DHFR inhibitors. Cell cycle arrest results indicated that compound 23 caused cell cycle arrest at the G0/G1 phase in the MCF-7 cells and at the G2/M phase in the Hep G2 cells. Compound 39 induced cell cycle arrest at the G2/M phase in Hela cells. In vivo testing of the anticancer activity of the two most promising molecules in this study was conducted, and the results indicated that they possess considerable in vivo anticancer activity in mice. Data obtained from the molecular modeling simulation study were consistent with the biological evaluation results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

A new series of N-[4-(2-substituted hydrazine-1-carbonyl)thiazole-2-yl]acetamides was synthesized and evaluated in vitro against six human cell lines as antitumor agents. Compounds 20, 21 and 22 showed remarkable inhibition to HeLa (IC 50 values of 1.67, 3.81, 7.92 µM) and MCF-7 (IC 50 values of 4.87, 5.81, 8.36 µM, respectively) cell growth with high selectivity indices and safety profiles. Compound 20 showed significant decreases in both tumor volume and body weight gain compared to vehicle control, in the solid tumor animal model of Ehrlich ascites carcinoma (EAC) with recovered caspase-3 immuno-expression. Flow cytometry cell analysis showed that 20 exerts anti-proliferative activity in mutant Hela and MCF-7 cell lines through arresting the cell growth at the G1/S phase producing cell death via apoptosis rather than necrosis. To explain the antitumor mode of action of the most active compounds, EGFR-TK and DHFR inhibition assays were carried out. Compound 21 conveyed dual EGFR/DHFR inhibition with IC 50 0.143 (EGFR) and 0.159 (DHFR) µM. Compound 20 showed DHFR inhibition with IC 50 0.262 µM. Compound 22 exhibited the best EGFR inhibitory efficacy with IC 50 0.131 µM. Molecular modelling study revealed that 21 and 22 have binding interactions with EGFR amino acid residues Lys745 and Asp855. Compounds 20 and 21 showed affinity toward DHFR amino acid residues Asn64, Ser59 and Phe31. The ADMET profile and Lipinski's rule of five calculated for these compounds were acceptable. Compounds 20, 21 and 22 could be regarded as promising prototype antitumor agents for further optimization., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

New 2-mercapto-quinazolin-4-one analogs were synthesized and tested for their in vitro anticancer activity, dihydrofolate reductase (DHFR) inhibition, and epidermal growth factor tyrosine kinase (EGFR-TK) inhibition activities. Compound 24, which is characterized by a 2-benzyl-thio function, showed broad-spectrum anticancer activity with high safety profile and selectivity index. The concentrations of 24 causing 50% growth inhibition (GI 50 ) and total cell growth inhibition (TGI) and its lethal concentration 50 (LC 50 ) were 15.1, 52.5, and 91.2 µM, respectively, using 5-fluorouracil as a positive control. Also, it showed EGFR-TK inhibitory activity with IC 50  = 13.40 nM compared to gefitinib (IC 50  = 18.14 nM) and DHFR inhibitory potency with 0.30 μM compared to methotrexate (MTX; IC 50  = 0.08 μM). In addition, compound 24 caused cell cycle arrest and apoptosis on COLO-205 colon cancer cells. Compounds 37, 21, and 54 showed remarkable DHFR inhibitory activity with IC 50 values of 0.03, 0.08, and 0.08 μM, respectively. The inhibitory properties of these compounds are due to an electron-withdrawing group on the quinazolinone ring, except for compound 54. In a molecular modeling study, compound 24 showed the same binding mode as gefitinib as it interacted with the amino acid Lys745 via π-π interaction. Compound 37 showed a similar binding mode as MTX through the binding interaction with Lys68, Asn64 via hydrogen bond acceptor, and Phe31 via arene-arene interaction. The obtained model and substitution pattern could be used for further development., (© 2022 Deutsche Pharmazeutische Gesellschaft.)

New series of thiazole and imidazo[2,1-b]thiazole derivatives were synthesized and tested for their in vitro anticancer activity. Compounds 27, 34, 39 and 42-44 showed the best anticancer activity against the tested cancer cell lines with high safety profile and selectivity indices, especially MCF-7 breast cancer, compared to sorafenib. As an attempt to reveal their mode of cytotoxicity, EGFR, HER2 kinase and DHFR inhibition assays were performed. Compounds 39 and 43 were the most potent dual EGFR/HER2 kinase inhibitors, with IC 50 values of 0.153 (EGFR), 0.108 (HER2) and 0.122 (EGFR), 0.078 (HER2) μM, respectively. 39 and 42 were the best DHFR inhibitors showing IC 50 0.291 and 0.123 μM, respectively. 39 and 43 induced their cytotoxicity via cell cycle arrest at G1/S and G1 phases, respectively, and apoptosis rather than necrosis in the MCF-7 breast cancer cell line. In vivo anti-breast cancer assay of 39 and 43 showed significant tumor volume reduction with recovered caspase-3 immunoexpression. Modeling study results proved the importance of the 5-(4-substituted phenyl)-imidazo[2,1-b]thiazole moiety and the hydrazide side chain for the anticancer activity. The most potent compounds showed good drug-likeness features and could be used as prototypes for further optimization. 39 could be an example of a multi-targeting anticancer agent that acts by inhibiting EGFR/HER2 kinase, DHFR enzymes and cellular apoptosis., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

A novel series of phthalimide derivatives was synthesized and evaluated for in vitro antitumor activity against six human cancer cell lines; HepG-2, HCT-116, MCF-7, Hep2, PC3 and Hela.The obtained results revealed that compound 32 was the most potent antitumor, while compounds 33, 22 and 24 showed strong activity against all tested cell lines. Further biological evaluation of the most active compounds was done and their in vitro EGFR-TK inhibition was tested, and the results came in accordance with the results of antitumor testing, where 32 displayed promising inhibitory activity (IC 50  = 0.065 µM) compared to the standard drug erlotinib (IC 50  = 0.067 µM). In addition, compounds 48, 22, 28 and 19 showed strong inhibitory activity (IC 50  = 0.089, 0.093, 0.147 and 0.152 µM respectively). Cell cycle analysis was conducted and the results revealed that 32 induced cell cycle arrest on Hela and MCF-7 at G0-G1 phase and Pre-G1 phase causing cell death mainly via apoptosis. Additionally, in vivo antitumor screening revealed that 32 reduced both body weight and tumor volume in solid tumor utilizing Ehrlich ascites carcinoma (EAC) animal model. Molecular modeling study showed that 32 and 48 have the highest affinity for binding with the active site of EGFR-TK with docking score comparable to erlotinib. Compounds 32 and 48 could be used as template models for further optimization., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Novel series of imidazo[2,1-b]thiazole analogs were designed, synthesized, and biologically evaluated as indoleamine 2,3-dioxygenase (IDO1) inhibitors. Imidazo[2,1-b]thiazoles 6, 7, and 8 showed inhibitory profiles against IDO1 at IC 50 values of 68.48, 82.39, and 48.48 nM, respectively, compared with IDO5L at IC 50 67.40 nM. Benzo[d]imidazo[2,1-b]thiazoles 17, 20, and 22 showed promising IDO1 inhibition at IC 50 values of 53.58, 53.16, and 57.95 nM, respectively. Compound 7 showed a growth-inhibitory profile at GI of 39.33% against the MCF7 breast cancer cell line, while 8 proved lethal to ACHN renal cancer cells. Cells treated with compounds 17 and 22 showed a typical apoptosis pattern of DNA fragments that reflected the G0/G1, S, and G2/M phases of the cell cycle, together with a pre-G1 phase corresponding to apoptotic cells, which indicates that cell growth arrest occurred at the S phase. Molecular modeling simulations validated the potential of benzo[d]imidazo[2,1-b]thiazole analogs to chelate iron(III) within the IDO1 binding pocket and, hence, to have a better binding affinity via hydrophobic-hydrophobic interactions., (© 2021 Deutsche Pharmazeutische Gesellschaft.)

Inhibiting the Dihydrofolate reductase (DHFR) enzyme has been validated in multiple clinical manifestations related to bacterial infection, malaria, and multiple types of cancer. Herein, novel series of 3-methyl-imidazo[2,1-b] thiazole-based analogs were synthesized and biologically evaluated for their in vitro inhibitory profile towards DHFR. Compounds 22 and 23 exhibited potent inhibitory profile targeting DHFR (IC 50 0.079 and 0.085 µM, respectively comparable to MTX IC 50 0.087 µM). Compounds 22 and 23 showed promising cytotoxicity against MCF7 breast cancer cell lines inducing cell cycle arrest and apoptosis. Furthermore, Compound 23 showed its potential to reduce body weight and tumor volume significantly, using Ehrlich ascites carcinoma (EAC) solid tumor animal model of breast cancer, compared to control-treated groups. Further, molecular modeling simulations validated the potential of 22 and 23 to have high affinity binding towards Arg22 and Phe31 residues via π-π interaction and hydrogen bonding within DHFR binding pocket. Computer-assisted ADMET study suggested that the newly synthesized analogs could have high penetration to the blood brain barrier (BBB), better intestinal absorption, non-inhibitors of CYP2D6, adequate plasma protein binding and good passive oral absorption. The obtained model and pattern of substitution could be used for further development of DHFR inhibitors., (Copyright © 2021 Elsevier Inc. All rights reserved.)

A new series of 6-substituted amido, azo or thioureido-quinazolin-4(3H)-one was synthesized and tested for their in-vitro antitumor activity. Compounds 21, 53 and 60 showed broad spectrum antitumor activity with average IC 50 values of 6.7, 7.6 and 9.1 μM, respectively compared with methotrexate (1, IC 50 19.26 μM). As an attempt to reveal the mechanism of the antitumor potency, cell cycle analysis and DHFR inhibition were performed. Compounds 59 and 61 induced their cytotoxicity in Hela (IC 50 10.6 μM) and HCT-116 (IC 50 15.5 μM) cell lines, respectively through Pre-G1 apoptosis, inhibiting cell growth at G2-M phase. Compounds 29, 33, 59 and 61 showed DHFR inhibitory potency at IC 50 0.2, 0.2, 0.3 and 0.3 μM, respectively. The active DHFR inhibitors showed high affinity binding toward the amino acid residues Thr56, Ser59 and Ser118. The active compounds obeyed Lipinski's rule of five and could be used as template model for further optimization., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A new series of 1,3-thiazoles and thiazolo[4,5-d]pyridazine both bearing the 2-thioureido function were designed, synthesized and evaluated for their invitro DHFR inhibition and antitumor activities. Compound 26 proved to be the most active DHFR inhibitor (IC 50 of 0.06μM). Compound 4, 20 and 21 showed in vitro antitumor activity against a collection of cancer cell lines. Compound 26 proved lethal to HS 578T breast cancer cell line with IC 50 value of 0.8μM, inducing cell cycle arrest and apoptosis. Molecular modeling studies concluded that recognition with key amino acids Phe 31 and Arg 22 is essential for DHFR binding. The obtained model could be useful for the development of new class of DHFR inhibitors., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A new series of 2-mercapto-quinazolin-4-one analogues was designed, synthesized and evaluated for their in vitro DHFR inhibition, antitumor and antimicrobial activity. Compound 17 proved to be the most active DHFR inhibitor with IC 50 value of 0.01μM, eight fold more active than methotrexate (MTX). Compounds 16 and 24 showed antitumor activity against human Caco2 colon and MCF-7 breast tumor cell lines with IC 50 values of 25.4 and 9.5μg/ml, respectively. Compounds 15, 20, 21 and 30 showed considerable activity against the Gram-positive bacteria Staphylococcus aureus while 24 and 30 proved active against Bacillus subtilis with a magnitude of potency comparable to the broad spectrum antibiotic Ciprofloxacin. Strong activity was observed for 13, 14, 19, 20 and 24 against Candida albicans and Aspergillus flavus. Compound 17 shared a similar molecular docking mode with MTX and made a critical hydrogen bond and arene-arene interactions via Ala9 and Phe34 amino acid residues, respectively., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A new series of 2-(1,3,4-thiadiazolyl- or 4-methyl-thiazolyl)thio-6-substituted-quinazolin-4-one analogs was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 29, 34, and 39 proved to be the most active DHFR inhibitors with IC50 values range of 0.1-0.6 μM. Compounds 28, 31 and 33 showed remarkable broad-spectrum antimicrobial activity comparable to the known antibiotic Gentamicin. Compounds 26, 33, 39, 43, 44, 50, 55 and 63 showed broad spectrum antitumor activity with GI values range of 10.1-100%. Molecular modeling study concluded that recognition with key amino acid Glu30, Phe31 and Phe34 is essential for binding. ADMET properties prediction of the active compounds suggested that compounds 29 and 34 could be orally absorbed with diminished toxicity., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

A novel series of 2-acetamido- or 2-propanamido-4-(4-substituted phenyl)-1,3-thiazoles (11-34) was designed and synthesized. Compounds were subjected to National Cancer Institute (NCI) in vitro assessment for their antitumor activity, at a single dose of 10 μM. Most of the investigated compounds exhibited broad-spectrum antitumor activity. Compounds 19 and 28 believed to be the most active members in this study, with MG-MID GI(50), TGI, and LC(50) values of 2.8, 11.4, 44.7; and 3.3, 13.1, 46.8, respectively. Compounds 19 and 28 proved to be nine and sevenfold more active than the standard antitumor drug 5-FU, respectively., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A novel series of 2-acetamido and 2 or 3-propanamido derivatives of 4- or 5-substituted-thiazoles was designed and synthesized. Structure elucidation of the new synthesized compounds was attained by the use of (1)H &(13)C NMR, and Mass spectrometry. Compounds were subjected to NCI in vitro assessment for their antitumor activity, at a single dose of 10 μM of test compounds. Compounds bearing straight chain substituent or 4-phenyl function proved to be more active than their branched or 4-methyl congeners. Compounds 37, 41 and 42 exhibited broad spectrum antitumor activity. Compounds 23 and 27 proved lethal while compounds 18, 21, 32 and 37 showed remarkable GI values of 75.5, 69.3, 96.2 and 92.7% to the Leukemia CCRF-CEM cell line, respectively., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

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., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The synthesis of some new heterodiazole and their annulated imidazo[2,1-b]1,3,4-oxa/thiadiazolone 6a-d, 7a-d; 1,3,4-oxa or thiadiazole[3,2-a]pyrimidine diamine 8a-d and 1,3,4-oxa or thiadiazole-3-piperidino-1-propamide 11a,b derivatives have been described. The obtained compounds were evaluated for their in-vitro antitumor activity. A single dose (10 μM) of the test compounds were used in the full National Cancer Institute (NCI) 60 cell lines panel assay. Compounds 6c and 6d displayed appreciable anticancer activity against leukemia, non-small cell lung, CNS and showed moderate activity against colon, melanoma, and breast cancer cells lines. Compound 6c possessed remarkable broad-spectrum antitumor activity which almost 4 fold more active than the known drug 5-FU with GI(50), TGI, and LC(50) values of 6.0, 17.4, and 55.1 μM, respectively., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

A new series of 2,6-substituted-quinazolin-4-ones was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 22, 33-37, 39-43, and 45 proved to be active DHFR inhibitors with IC(50) range of 0.4-1.0microM. Compound 18 showed broad-spectrum antimicrobial activity comparable to the known antibiotic gentamicin. Compounds 34 and 36 showed antitumor activity at GI(50) (MG-MID) concentrations of 11.2, and 24.2microM, respectively. Molecular modeling study including flexible alignment; electrostatic, hydrophobic mappings; and pharmacophore prediction were performed. A main featured pharmacophore model was developed which justifies the importance of the main pharmacophoric groups as well as of their relative distances. The substitution pattern and spatial considerations of the pi-systems in regard to the quinazoline nucleus proved critical for biological activity., (Copyright 2010 Elsevier Ltd. All rights reserved.)

A series of 3,5-bis(arylidene)-4-piperidones like chalcone analogues carrying variety of methoxylated aryl groups, pyrazolo[4,3-c]pyridines, pyrido[4,3-d]pyrimidines, and pyrido[3,2-c]pyridines, carrying an arylidene moiety, and some pyrano[3,2-c]pyridines, like flavone and coumarin isosteres, were synthesized and screened for their in-vitro antitumor activity at the National Cancer Institute (NCI, USA). The tested compounds 7, 9, 10, 12, 13, 15, 17, and 19 exhibited a broad spectrum of antitumor activity. Compounds belonging to the pyrazolo[4,3-c]pyridine series proved to be more active than those of the pyrido[3,2-c]pyridine and pyrano[3,2-c]pyridine analogues, in which the monomethoxylated derivatives showed better antitumor activity when compared with their corresponding dimethoxylated congeners. Compound 7 is considered to be the most active member identified in this study with a broad spectrum of activity against 22 different tumor cell lines belonging to the nine subpanels employed, and a particular effectiveness against the breast cancer T-47D cell line (GI 54.7%). The pyrano[3,2-c]pyridine heterocyclic system 19 proved to be the most active antitumor agent among the six-membered fused pyridines, with variable activity against 18 different tumor cell lines, and special activity against the non-small cell lung cancer Hop-92 and ovarian cancer OVCAR-4 cell lines (GI values 63.9 and 48.5%, respectively).

The synthesis of some new 2-thieno-4(3H)-quinazolinone derivatives and their biological evaluation as antitumor agents using the National Cancer Institute (NCI) disease oriented antitumor screen protocol are investigated. Compounds 2-(2-thienylcarbonylamino)-5-iodo-N-(4-hydroxyphenyl)-benzamide (16), 2-(2-thieno)-6-iodo-3-phenylamino-3,4-dihydro-quina-zolin-4-one (26), and 2-(2-thieno)-4-[4-sulfonamidobenzylamino]-6-iodo-quinazoline (42), with GI(50) values of 12.7, 10.3, 16.9 microM, respectively, proved to be the most active members in this study, as compared to the known drug 5-FU. Conformational analysis of the most active molecules using molecular modeling and QSAR techniques enabled the understanding of the pharmacophoric requirements for 2-thieno-quinzolinone derivatives as antitumor agents. These three quinazolinone analogs (16, 26, 42) could be considered as useful templates for future development to obtain more potent antitumor agents.

In order to produce potent new leads for anticancer drugs, a new series of quinazoline analogs was designed to resemble methotrexate (MTX, 1) structure features and fitted with functional groups believed to enhance inhibition of mammalian DHFR activity. Molecular modeling studies were used to assess the fit of these compounds within the active site of human DHFR. The synthesized compounds were evaluated for their ability to inhibit mammalian DHFR in vitro and for their antitumor activity in a standard in vitro tissue culture assay panel. Compounds 28, 30, and 31 were the most active DHFR inhibitors with IC(50) values of 0.5, 0.4, and 0.4microM, respectively. The most active antitumor agents in this study were compounds 19, 31, 41, and 47 with median growth inhibitory concentrations (GI(50)) of 20.1, 23.5, 26.7, and 9.1microM, respectively. Of this series of compounds, only compound 31 combined antitumor potency with potent DHFR inhibition; the other active antitumor compounds (19, 41, and 47) all had DHFR IC(50) values above 15microM, suggesting that they might exert their antitumor potency through some other mode of action. Alternatively, the compounds could differ significantly in uptake or concentration within mammalian cells.

A 1, 4-dihydropyridine <--> pyridinium salt type redox system is described as a general and flexible method for site-specific and sustained delivery of drugs to the brain. This concept was used in the present investigation as a model to deliver an alkylating antitumor agent into the brain. A bis-(chloroethyl)amine drug was hooked to 1, 4-dihydropyridine chemical delivery system (CDS) through an amide linkage. Five new-target compounds (23-27) of the 1, 4-dihydropyridine CDS type were synthesized through the reduction of five new pyridinium quaternary intermediates (18-22). The synthesized 1, 4-dihydropyridines were subjected to various chemical and biological investigations to evaluate their ability to cross the blood-brain barrier (BBB), and to be oxidized biologically into their corresponding quaternary compounds. The in vitro oxidation studies showed that 1-benzyl-3-[N-[2-bis(2-chloroethyl)aminoethyl]-carbamoyl]-1, 4-dihydropyridine (23) and 1-(4-nitrobenzyl)-3-[N-[2-bis(2-chloroethyl)aminoethyl ]carbamoyl]-1, 4-dihydropyridine (27) could be oxidized into their corresponding quaternary compounds 18 and 22 respectively, at an adequate rate, which ensure the release of the carried anticancer drug. The in vivo studies showed that compound 23 was able to cross the BBB at detectable concentrations. On the other hand, the in vitro alkylation activity studies revealed that 1-(4-nitrobenzyl)-3-[N-[2-bis(2-chloroethyl)aminoethyl]carbamoyl]pyridinium bromide (22) is an alkylating agent with activity comparable to the known drug chlorambucil.

A new series of 2-substituted mercapto-3H-quinozolines bearing 6-iodo and 2-heteroarylthio functions was synthesized and screened for their in vitro antitumor activity. Eighteen compounds were identified as active anticancer agents. N'-[(3-Benzyl-4-oxo-6-iodo-3H-quinazoline-2-yl)thioacetyl]-N(3)-ethylthiosemicarbazide (10), N-benzoyl-N'-[2-(3-benzyl-4-oxo-6-iodo-3H-quinozolin-2-yl)thioacetyl]hydrazine (12), and 2-[(3, 6-dioxo-pyridazin-4-yl)thio]-3-benzyl-4-oxo-6-iodo-3H-quinazoline (20) proved to be the most active members in this study. They showed MG-MID, GI(50) values of 12.8, 11.3, and 13.8 microM, respectively. The detailed synthesis and biological screening data are reported.

Abstract: A new series of tetrahydro-quinazoline and tetrahydro-1H-dibenzo[b,e][1,4]diazepine analogs were synthesized and tested for their DHFR inhibition and in vitro antitumor activity. Compound 35 showed a remarkable DHFR inhibitory potency (IC50, 0.004 μM) which is twenty fold more active than methotrexate (MTX). Compounds 17 and 23 proved to be fifteen fold more active than the known antitumor 5-FU, with MG-MID GI50, TGI, and LC50 values of 1.5, 46.8, 93.3 and 1.4, 17.4, 93.3 μM, respectively. Computer modeling studies allowed the identification that methoxy and methyl substituents, the π-system of the chalcone core, the nitrogen atoms, on the dibenzodiazepine ring as pharmacophoric features essential for activity. These mark points could be used as template model for further future optimization. [Copyright &y& Elsevier]

A new series of 2,3,6-substituted-quinazolin-4-ones was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 28 and 61 proved to be active DHFR inhibitors with IC 50 0.02 and 0.01 μM, respectively. Molecular modeling studies concluded that recognition with the key amino acid Phe34 is essential for binding and hence DHFR inhibition. Compounds 34 , 56 and 66 showed broad spectrum antimicrobial activity comparable to Gentamicin and Ciprofloxacin. Compounds 40 and 64 showed broad spectrum antitumor activity toward several tumor cell lines and proved to be 10 fold more active than 5-FU, with GI 50 MG-MID values of 2.2 and 2.4 μM, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A new series of compounds possessing 5-(2-aminothiazol-4-yl)-4-phenyl-4H-1,2,4-triazole-3-thiol skeleton was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, antitumor and schistosomicidal activities. Four active compounds were allocated, the antibacterial 22 (comparable to gentamicin and ciprofloxacin), the schistosomicidal 29 (comparable to praziquantel), the DHFR inhibitor 34 (IC50 0.03 μM, 2.7 fold more active than MTX), and the antitumor 36 (comparable to doxorubicin). Molecular modeling studies concluded that recognition with key amino acid Leu4 and Val1 is essential for DHFR binding. Flexible alignment and surface mapping revealed that the obtained model could be useful for the development of new class of DHFR inhibitors. [Copyright &y& Elsevier]

Abstract: A new series of 2-heteroarylthio-6-substituted-quinazolin-4-one analogs was designed, synthesized, and evaluated for their in vitro DHFR inhibition, antimicrobial, and antitumor activities. Compounds 21, 25, and 39 proved to be active DHFR inhibitors with IC50 range of 0.3–0.8 μM. Compounds 25, 28, 33, 35 and 36 showed broad spectrum antimicrobial activity comparable to the known antibiotic gentamicin. Compound 29 showed broad spectrum antitumor activity toward several tumor cell lines with GI values range of 25.8–41.2%. Molecular modeling studies concluded that recognition with key amino acid Arg38 and Lys31 are essential for binding and biological activities. Flexible alignment; electrostatic and hydrophobic mappings revealed that the obtained model could be useful for the development of new DHFR inhibitors. [Copyright &y& Elsevier]

Abstract: A novel series of thiazolo[2,3-b]quinazoline (14–23, 26 and 27), and pyrido[4,3-d]thiazolo[3,2-a]pyrimidine (34–43, 45 and 46) analogues were designed and synthesized. The obtained compounds were evaluated for their in-vitro antitumor activity at the National Cancer Institute (NCI) 60 cell lines panel assay. Compounds 22, 38, 40 and 41 showed remarkable broad-spectrum antitumor activity. Compounds 22 and 38 are almost nine fold more active than 5-FU, with GI50, TGI, and LC50 values of 2.5, >100, >100; and 2.4, 9.1, 36.2 μM, respectively; while 40 and 41 are almost seven fold more active than 5-FU, with GI50, TGI, and LC50 values of 2.9, 12.4, 46.6 and 3.0, 16.3, 54.0 μM, respectively. [Copyright &y& Elsevier]