Synthesis and in vitro antitumor activity of substituted quinazoline and quinoxaline derivatives: search for anticancer agent

The synthesis of some 2-furano-4(3H)-quinazolinones, diamides (open ring quinazolines), quinoxalines and their biological evaluation as antitumor agents using National Cancer Institute (NCI) disease oriented antitumor screen protocol are investigated. Among the synthesize compounds, seventeen compounds were granted NSC code and screened at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10(-5) M) in full NCI 60 cell panel. Among the selected compounds, 3-(2-chloro benzylideneamine)-2-(furan-2-yl) quinazoline-4(3h)-one 21 was found to be the most active candidate of the series at five dose level screening against Ovarian OVCAR-4 and Non-small cell lung cancer NCI-H522 with GI50 1.82 & 2.14 μM respectively. Rational approach and QSAR techniques enabled the understanding of the pharmacophoric requirement for quinazoline, diamides and quinoxaline derivatives.     

Synthesis, molecular structure, and in vitro antitumor activity of new 4-chloro-2-mercaptobenzenesulfonamide derivatives

The reaction of 3-amino-2-(2-alkylthio-4-chlorobenzenesulfonyl)guanidines 2a-j with 1,2-dicarbonyl compounds are described. Depending on structure of 1,2-dicarbonyl reagent novel 2-alkylthio-5-chloro-N-(1,2,4-triazin-3-yl)benzenesulfonamides 3-15, 1-(2-alkylthio-4-chlorobenzenesulfonyl)-3-(2-oxobutane-3-ylidenoimino)guanidines 16-18 and 2-alkylthio-4-chloro-N-(1,2-dihydroxycyclobuta[e]1,2,4-triazin-3-yl)benzenesulfonamides 19-21 are obtained. The structures of these compounds were confirmed on the basis of elemental analysis, spectral data and X-ray analysis. The compounds 4, 5, 7, 9, 10, 12-15, 17, 18 and 20 were screened at the National Cancer Institute (NCI) for their in vitro activities against a panel of 56 tumor cell lines and relationship between structure and antitumor activity are discussed. The compounds 10, 12, 17 and 20 were inactive, whereas the other compounds exhibited reasonable activity against one or more human tumor cell lines. The prominent compound 18 showed significant activity against cell lines of colon cancer (HCT-116), renal cancer (786-0) and melanoma (M14) (GI50 in the range 0.33-1.08 microM) as well as good selectivity toward non-small cell lung cancer (HOP-62) cells (GI50 = 0.05 microM, TGI = 0.38 microM and LC50 = 4.83 microM).     

Synthesis and in vitro cysticidal activity of new benzimidazole derivatives

Despite albendazole being the drug of choice in neurocysticercosis treatment, its low solubility limits its bioavailability; therefore, more research is required in order to find new molecules with cestocidal activity and adequate aqueous solubility. A set of 13 benzimidazole derivatives were synthesized and their in vitro activities were evaluated against Taenia crassiceps cysts, using albendazole sulfoxide as reference molecule, showing that two of them exhibited good activity. Molecular modelling revealed that the cysticidal efficacy depends on the presence on the molecule of an H in the 1-position, a planar carbamate group at 2-position, and if the substituent in 5-position is voluminous, it should be orthogonal to the benzimidazole ring.     

Synthesis and in vitro antitumor activity of novel series 2-benzylthio-4-chlorobenzenesulfonamide derivatives

Three series of novel 2-benzylthio-4-chloro-5-R1-benzenesulfonamides bearing the N-(benzoxazol-2-yl) (10-19), N-(benzothiazol-2-yl) (20-21) or N-(1,3-dihydro-2H-benzimidazol-2-ylidene) (22-25) moiety were synthesized by reacting N-(2-benzylthio-4-chloro-5-R1-benzenesulfonyl)cyanamide potassium salts (5-9) with 2-aminophenols, 2-aminothiophenol and o-phenylenediamines, respectively. Compounds with carbamoyl substituent at position 5 (14-16, 21 and 25, R1=CONH2) were further dehydrated to the corresponding nitriles (26-30, R1=CN). The in vitro antitumor activity of the compounds obtained was determined at the National Cancer Institute (NCI), and the structure-activity relationships were discussed. N-(2-benzoxazolyl)-2-benzylthio-4-chloro-5-(4-fluorophenylcarbamoyl)benzenesulfonamide (18) is the prominent of the compounds due to its remarkable activity and selectivity toward non-small cell lung cancer (NCI-H522) and melanoma (SK-MEL-2) cell lines (GI50=0.1 microM, TGI=0.5-0.6 microM).     

Synthesis and in vitro antibacterial activity of new steroidal thiosemicarbazone derivatives

We investigated the antibacterial activity of some new steroidal thiosemicarbazone derivatives, prepared from the reaction of cholest-5-en-7-one with thiosemicarbazides, in ethanol in the presence of a few drops of HCl at 80 degrees C in high yield. All the compounds have been characterized by means of elemental analyses, IR, 1H NMR and mass spectroscopic data, to find an effective antibacterial agent. The antibacterial activity was first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) of compounds was determined. The results showed that the steroidal thiosemicarbazones derivatives inhibit growth of both types of the bacteria (Gram-positive and Gram-negative). The acetoxy and chloro derivatives of cyclopentyl and cyclohexyl amine thiosemicarbazones were found to have more antibacterial activity than the other derivatives.     

Synthesis and in vitro antitumor activities of novel 4-anilinoquinazoline derivatives

A series of 6, 7-dialkoxy-4-anilinoquinazolines were designed, synthesized by substituting different heterocycles on 6-position and a variety of anilines on 4-position of the quinazoline. These novel quinazoline compounds were screened for their cytotoxic effect on epidermal growth factor receptor overexpressing skin epidermoid carcinoma cell line (A431), by using nonoverexpressing tumor cells as negative control (breast adeno carcinoma cell line MCF-7). 2-Butyl-4-chloro-1-{3-[7-methoxy-4-(3-(trifluoromethyl)phenylamino)quinazolin-6-yloxy]-propyl}-1H-imidazole-5-carboxaldehyde (30) and 2-butyl-4-chloro-1-{3-[4-(3-iodophenyl amino)-7-methoxyquinazolin-6-yloxy]propyl}-1H-imidazole-5-carboxaldehyde (33) were found to be more potent against A431 cell line (IC(50) 3.5 and 3 microM) and their activities are comparable to gefitinib. Insilico docking experiments with human EGFR Tyrosine kinase domain (PDB id-2gs2) indicated that 33 docks at the same position as that of gefitinib involving Val702, Ala719, Ser696, and Lys721.     

Synthesis and antitumor activity of new sulfonamide derivatives of thiadiazolo[3,2-a]pyrimidines

New series of sulfonamide derivatives of [1,3,4]thiadiazolo[3,2-a]pyrimidine were synthesized and investigated as antitumor agents. Some of the newly prepared compounds were tested for their in vitro and in vivo antitumor activities. Preliminary biological studies revealed that compounds 4c, 4f, and 4j exhibited the highest affinity to DNA, while compounds 4h,i, 6a-c, 8 and 12-14 exhibited moderate activity. Also, compounds 4j, 4f and 4c showed the highest percentage increase in lifespan of mice inoculated with Ehrlich ascites cells over 5-flurouracil (positive control). The detailed synthesis, spectroscopic and biological data are reported.     

Synthesis and antitumor activity of ring A modified glycyrrhetinic acid derivatives

Triterpenoic acids show many pharmacological effects, among them an antiinflammatory or an antitumor activity. One of these, glycyrrhetinic acid (1) is of interest because of its antitumor profile. Glycyrrhetinic acid is not only cytotoxic but also triggers apoptosis in various human tumor cell lines. To improve the cytotoxicity of parent 1 we set out to synthesize new derivatives of it – differing in structure and lipophilicity. These compounds were tested in a sulforhodamine B assay for cytotoxicity, and screened for their ability to induce apoptosis using an acridine orange/ethidium bromide assay and trypan blue staining. The most active compound, 34, a benzyl glycyrrhetinate holding an extra 3-N-(3-aminopropyl)glycyl substituent showed IC₅₀ between 1.96 and 5.14 μm for five human cancer cell lines and triggers apoptosis in 80% of the cells.     

Synthesis and antituberculosis activity of new thiazolylhydrazone derivatives

The increasing clinical importance of drug-resistant mycobacterial pathogens has lent additional urgency to microbiological research and new antimycobacterial compound development. For this purpose, new thiazolylhydrazone derivatives were synthesized and evaluated for antituberculosis activity. The reaction of thiosemicarbazide with acetophenone derivatives gave 1-(1-arylethylidene)thiosemicarbazide (1). The N-(1-arylethylidene)-N'-[4-(indan-5-yl)thiazol-2-yl]hydrazone (3) derivatives were synthesized by reacting 1-(1-arylethylidene)thiosemicarbazide with 1-(5-indanyl)-2-bromoethanone (2). The chemical structure of the compounds was elucidated by elemental analyses, IR, (1)H NMR, MS-FAB(+) spectral data. Antituberculosis activities of the synthesized compounds were determined by broth microdilution assay, the Microplate Alamar Blue Assay, in BACTEC12B medium and the results were screened in vitro, using BACTEC 460 Radiometric System against Mycobacterium tuberculosis H(37)Rv (ATCC 27294) at 6.25 microg/ml and some of the tested compounds showed important inhibition ranging from 92% to 96%. The compounds were also investigated for their cytotoxic properties on normal mouse fibroblast (NIH/3T3) cell line and the results obtained here showed that all the compounds used have no significant cytotoxicity at the concentrations under 50 microg/ml.     

Synthesis and biological activity of some antitumor active derivatives from glycyrrhetinic acid

Aminoalkyl substituted derivatives were synthesized starting from glycyrrhetinic acid methyl ester and screened for antitumor activity in a panel of 15 human cancer cell lines by an SRB assay. The most compound 7 possesses an aminohexyl side chain, induces apoptosis and shows IC50 values of 0.6-3.0 μM.     

Synthesis and antitubercular activity of new mefloquine-oxazolidine derivatives

In this work, we report the synthesis and the antitubercular evaluation of 16 new mefloquine derivatives, formed from reactions between mefloquine and benzaldehydes, with the activity expressed as the minimum inhibitory concentration (MIC) in μM. The compounds were non-cytotoxic and exhibited an important activity (12.6 μM). The appreciable activity of these compounds can be considered an important finding for the rational design of new leads for anti-TB compounds.     

Synthesis and anticandidal activity of new triazolothiadiazine derivatives

New triazolothiadiazine derivatives were synthesized via the ring closure reaction of 4-amino-5-substituted-2,4-dihydro-3H-1,2,4-triazol-3-thiones with phenacyl bromides. The compounds were tested in vitro against various Candida species and compared with ketoconazole. Among these compounds, the compound bearing cyclohexyl moiety and p-chlorophenyl substituent on triazolothiadiazine ring (2i) was found to be the most potent derivative against Candida albicans (ATCC 90028). It is clear that there is a positive correlation between anticandidal activity and two functional moieties, namely cycloaliphatic group and p-chlorophenyl substituent on triazolothiadiazine ring. The compounds were also investigated for their cytotoxic effects using MTT assay. Compound 2a exhibited the highest cytotoxic activity, whereas compound 2f possessed the lowest cytotoxic activity against NIH/3T3 cells.     

Synthesis and antimalarial activity of new atovaquone derivatives

In this paper we describe the design and synthesis of 18 derivatives of the antimicrobial atovaquone which were substituted at the 3-hydroxy group by ester and ether functions. The compounds were evaluated in vitro for their activity against the growth of Plasmodium falciparum, the malaria causing parasite. All the compounds showed potent activity, with IC₅₀ values in the range of 1.25–50 nM, comparable to those of atovaquone and much higher than chloroquine or quinine.     

Synthesis of a new series of 4-chloro-2-mercapto-5-methylbenzenesulfonamide derivatives with potential antitumor activity

The syntheses of S-(5-chloro-4-methyl-2-sulfamoylphenyl)alkanethio (or benzothio)hydrazonates (3a-3o) and potassium S-(5-chloro-2-cyanoamidatesulfonyl-4-methylphenyl)alkanethio (or benzothio)hydrazonates (4-10) are described. The compounds 3e, 3i-3o, 7 and 8 were screened at the National Cancer Institute (NCI) for their activities against a panel of 59 tumor cell lines and relationships between structure and antitumor activity in vitro are discussed. The compounds 3e, 3j, 3l-3o and 7 exhibited reasonable activity against numerous human tumor cell lines. The prominent compound 3l showed significant activity against some cell lines of leukemia (SR), melanoma (SK-MEL-5), CNS cancer (SF-539), ovarian cancer (OVCAR-3, OVCAR-4) and breast cancer (MDA-MB-231/ACTT) (GI50 values in the range 0.3-0.9 microM). Furthermore, compound 8 exhibited the high selectivity against renal cancer (A498) cells (GI50 < 0.01 microM, TGI = 2.3 microM and LC50 = 35.7 microM).     

Part I: Synthesis, cancer chemopreventive activity and molecular docking study of novel quinoxaline derivatives

The reaction of o-phenylene diamine and ethyl oxamate is reinvestigated and led to 3-aminoquinoxalin-2(1H)-one rather than benzimidazole-2-carboxamide as was previously reported. The structure of the obtained quinoxaline has been confirmed by X-ray. The anti-tumor activity of synthesized quinoxalines 1-21 has been evaluated by studying their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Among the studied compounds 1-21, compounds 12, 8, 13, 18, 17 and 19, respectively, demonstrated strong inhibitory effects on the EBV-EA activation without showing any cytotoxicity and their effects being stronger than that of a representative control, oleanolic acid. Furthermore, compound 12 exhibited a remarkable inhibitory effect on skin tumor promotion in an in vivo two-stage mouse skin carcinogenesis test using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter. The result of the present investigation indicated that compound 12 might be valuable as a potent cancer chemopreventive agent. Moreover, the molecular docking into PTK (PDB: 1t46) has been done for lead optimization of the aforementioned compounds as potential PTK inhibitors.     

Synthesis of new 2-acetyl and 2-benzoyl quinoxaline 1,4-di-N-oxide derivatives as anti-Mycobacterium tuberculosis agents

A series of 2-acetyl and 2-benzoyl-6(7)-substituted quinoxaline 1,4-di-N-oxide derivatives were synthesized and evaluated for in vitro antituberculosis activity. The results show that 2-acetyl-3-methylquinoxaline 1,4-di-N-oxide derivatives with chlorine, methyl or methoxy group in position 7 of the benzene moiety (compounds 2, 4 and 6, respectively) and unsubstituted (3) have good antitubercular activity, exhibiting EC(90)/MIC values between 0.80 and 4.29. In conclusion, the potency, selectivity and low cytotoxicity of these compounds make them valid leads for synthesizing new compounds that possess better activity.     

Synthesis, molecular docking study and antitumor activity of novel 2-phenylindole derivatives

The starting material, 4-(1-indol-2-yl)phenol 1 was obtained via Fischer synthesis. Vilsmeir Haack(')s formylation of 1 gave the carboxaldehyde derivative 2 which was subjected to different reactions affording the 3-substituted compounds 3-10. Compound 1 reacted with halo esters to give 11 and 12a,b. The reaction of 12a with various amino derivatives gave compounds 13-16. The hydrazide derivative 15a reacted with 1,3-diketones, ethyl acetoacetate and aromatic carboxylic acid derivatives to give 17a,b, 18 and 19a-e, respectively. Antitumor activity of target compounds were tested against breast cancer cell lines (MCF-7) and (MDA-MB-231). The most potent compound was 3e with IC(50)?=?1.60?nM against (MCF-7). Docking was performed on colchicine binding site of tubulin to study the binding mode of the designed compounds.     

Synthesis and in vitro activity of a series 1beta-methylcarbapenem derivatives

The synthesis of a new series of 1beta-methylcarbapenems having pyrrolidine and piperidine moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituent on the pyrrolidine ring was investigated. A particular compound (IIIb) having hydroxypyrrolidine moiety showed the most potent antibacterial activity.     

Synthesis, in vitro antimicrobial and in vivo antitumor evaluation of novel pyrimidoquinolines and its nucleoside derivatives

Seven series of pyrimidoquinoline derivatives have been synthesized, tetrazolo[4′,3′:-1,2]pyrimido[4,5-b]quinoline (3), 2-aminopyrimido[4,5-b]quinoline (4), triazolo[4′,3′:1,2]-pyrimidoquinoline (5a,b, 10), imidazolo[3′,2′:1,2]pyrimido[4,5-b]-quinoline (8a,b), 6-chloro-2-methylthiopyrimido[4,5-b]quinoline (12), acetylated nucleosides (16, 17a,b) and deacetylated nucleosides (18, 19a,b). Some of the novel pyrimidoquinoline derivatives possess highly activity toward the bacteria and fungi species. The new quinolines derivatives were evaluated for their anticancer activity toward human cancer cell lines by the National Cancer Institute (NCI). Most of them had excellent growth inhibition activity, having LD₅₀ values in the low micromolar to nanomolar concentration range.     

Synthesis, structural characterization and antitumor activity of novel 2,4-diamino-1,3,5-triazine derivatives

The syntheses, structural elucidation based on NMR spectroscopy and X-ray analysis of 8 as well as antitumor activities of novel 2,4-diamino-1,3,5-triazine derivatives 5 and 7-22 are described. Screenings performed at NCI showed that most derivatives possessed a moderate to strong growth inhibition activity on various tumor panel cell lines between 0.148 and 56.2 microM concentrations. 2-Amino-6-bromomethyl-4-(3,5,5-trimethyl-2-pyrazoline)-1,3,5-triazine 11 showed the most potent antitumor activity with the mean midpoint values of log(10) GI50, log(10) TGI50 and log(10) LC50 of all tests equal to -5.26, -4.81 and -4.37, respectively and therefore, it can be considered as a lead structure for further development of anticancer agents.