Synthesis, analgesic, anti-inflammatory, and antimicrobial activity of some novel pyrimido[4,5-b]quinolin-4-ones

Novel series of pyrimido[4,5-b]quinolines (3a-c), triazolo[4',3':1,2]pyrimido[4,5-b]-quinolines (7a-e, 9, and 14), tetrazolo[4',3':1,2]pyrimido[4,5-b]quinolin-5-one (13), [1,3]-pyrazolo[3',2':1,2]pyrimido[4,5-b]quinolines (12a and 12b), and 2-pyrazolyl-pyrimido[4,5-b]-quinolines (15, 16a, 16b, and 19) have been synthesized. Some of the new compounds were tested against various bacteria and fungi species. In addition, the analgesic and anti-inflammatory activities are reported. Compounds 8 and 9a possess high activity toward the fungi as compared with the reference drug Nystatin. The tested compounds 5 and 8 have moderate anti-inflammatory activities. Moreover compounds 5, 8, 10, and 16a, have activities higher than the reference drug in peripheral analgesic activity testing, Compounds 5, 7a, 11a, and 16a have potencies as the reference drug in central analgesic activity testing.     

Inhibition of Src kinase activity by 7-[(2,4-dichloro-5-methoxyphenyl)amino]-2-heteroaryl-thieno[3,2-b]pyridine-6-carbonitriles

7-[(2,4-Dichloro-5-methoxyphenyl)amino]thieno[3,2-b]pyridine-6-carbonitriles with various heteroaryl groups at C-2 are inhibitors of Src kinase activity. Of these new analogs, compounds substituted at C-2 by a 3,5-furan or a 2,5-pyridine had the best activity in the Src enzyme and cell assays.     

4-Anilino-3-cyanobenzo[g]quinolines as kinase inhibitors

A series of 4-anilino-3-cyanobenzo[g]quinolines was prepared as potent kinase inhibitors. Compared with their bicyclic 4-anilino-3-cyanoquinoline analogues, the tricyclic 4-anilino-3-cyanobenzo[g]quinolines are less active against EGF-R kinase, equally active against MAPK kinase (MEK), and more active against Src kinase. For Src kinase inhibition, the best activity is obtained when both the 7- and 8-positions are substituted with alkoxy groups. Several of these kinase inhibitors show potent growth inhibitory activity in tumor cells.     

Design, synthesis and evaluation of 5-substituted amino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines as novel antimalarials

Novel 5-substituted amino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines were designed based on a pharmacophore developed for potent antimalarial activity using Chem-X and MOE softwares. The designed molecules were synthesized by following a novel route and were evaluated by Rane's test for blood schizonticidal activity in mice infected by Plasmodium berghei. Based on the Mean Survival Time (MST) data, of the nine compounds evaluated, three had curative potential when compared with chloroquine.     

Solvent free microwave synthesis and evaluation of antimicrobial activity of pyrimido[4,5-b]- and pyrazolo[3,4-b]quinolines

A series of 2-oxopyrimido[4,5-b]-, 2-thio[4,5-b]-, 1-(p-tosyl)pyrazolo[3,4-b]- and 1-(2',4'-dinitrophenyl)pyrazolo[3,4-b]-quinolines have been synthesized in good to excellent yields by environmentally benign solvent free microwave-induced techniques involving the condensation of 2-chloro-3-formylquinolines with urea, thiourea, p-toluenesulfonylhydrazide and 2,4-dinitrophenylhydrazine, respectively, using PTSA as a catalyst. All the synthesized compounds were evaluated for their antibacterial and antifungal activities. Most of the compounds showed the best activity against Escherichia coli and Pseudomonas aeruginosa.     

Quinoline tricyclic derivatives. Design, synthesis and evaluation of the antiviral activity of three new classes of RNA-dependent RNA polymerase inhibitors

In this study three new classes of linear N-tricyclic compounds, derived by condensation of the quinoline nucleus with 1,2,3-triazole, imidazole or pyrazine, were synthesized, obtaining triazolo[4,5-g]quinolines, imidazo[4,5-g]quinolines and pyrido[2,3-g]quinoxalines, respectively. Title compounds were tested in cell-based assays for cytotoxicity and antiviral activity against RNA viruses representative of the three genera of the Flaviviridae family, that is BVDV (Pestivirus), YFV (Flavivirus) and HCV (Hepacivirus). Quinoline derivatives were also tested against representatives of other RNA virus families containing single-stranded, either positive-sense (ssRNA(+)) or negative-sense (RNA(-)), and double-stranded genomes (dsRNA), as well as against representatives of two DNA virus families. Some quinolines showed moderate, although selective activity against CVB-5, Reo-1 and RSV. However, derivatives belonging to all classes showed activity against BVDV. Among the most potent were the bis-triazoloquinoline 1m, the imidazoquinolines 2e and 2h, and the pyridoquinoxalines 4h, 4j and 5n (EC(50) range 1-5 μM). When tested in a replicon assay, compound 2h was the sole derivative to also display anti-HCV activity (EC(50)=3.1 μM). In enzyme assays, 1m, 2h, 5m and 5n proved to be potent inhibitors of the BVDV RNA-dependent RNA polymerase (RdRp), while only 2h also inhibited the recombinant HCV enzyme.     

Docking studies and development of novel 5-heteroarylamino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines as potential antimalarials

MOE-Dock (Docking software) was used to predict the binding modes of 10 novel and potent 5-substituted amino-2,4-diamino-8-chloropyrimido-[4,5-b]quinolines (compounds I-X) as part of our antimalarial drug development programme. This was done by analyzing the interaction of these compounds with the active sites of 11 enzymes present in Plasmodium falciparum and based on this, effective binding was observed to enzyme P. falciparum glutathione reductase (PfGR). The binding scores for compounds I-X with PfGR were also congruent with their antimalarial activity. Three additional analogs were then designed and synthesized based on the above docking study and the pharmacophoric requirements for this class.     

Structure and species as factors affecting the metabolism of some methoxy-6-sulphanilamidopyrimidines

1. A comparative study was made in man, rhesus monkey, rat and rabbit of the urinary excretion of 2-, 4- and 5-methoxy- and 2,4-, 2,5- and 4,5-dimethoxy-6-sulphanilamidopyrimidines given orally. 2. In the rabbit, 70-80% of the dose of each drug was excreted in 2 days, mainly as N(4)-acetyl derivatives, except 2,5-dimethoxy-6-sulphanilamidopyrimidine, which was mainly excreted unchanged. 3. In the rat, 50-70% of the dose of each drug was excreted in 2 days, except the 2-methoxy and 2,4-dimethoxy compounds, whose excretion was about 30%. The N(4)-acetyl derivatives accounted for 20-70% of the drugs excreted, except the 2,5-dimethoxy derivative, which was excreted unchanged. 4. In the rhesus monkey, some 40-60% of the dose of the 2-methoxy, 2,4-dimethoxy and 2,5-dimethoxy compounds was excreted in 2 days, but the 4-methoxy, 5-methoxy and 4,5-dimethoxy compounds were excreted at less than half this rate. The 4-methoxy, 5-methoxy and 4,5-dimethoxy compounds were highly acetylated (80-90%) whereas the 2-methoxy compound was poorly acetylated (17%) and the 2,5-dimethoxy compound hardly at all. The major metabolite of the 2,4-dimethoxy compound in the monkey was the N(1)-glucuronide. 5. In man, 30% of the dose of the 4-methoxy and 2,4-dimethoxy compounds was excreted in 24 hr., whereas the 4,5-dimethoxy compound (Fanasil) was very slowly excreted (12% in 2 days). The 4-methoxy compound was well acetylated (65%), but the 2,4- and 4,5-dimethoxy compounds were not (20-30%). The main metabolite of the 2,4-dimethoxy compound in man was the N(1)-glucuronide. 6. N(1)-Glucuronide formation occurred extensively only with the 2,4-dimethoxy compound and only in man and the rhesus monkey. It did not occur in the rabbit and only to a minor extent in the rat. 7. The 2,5-dimethoxy compound was not significantly acetylated in vivo in the rabbit, rat or monkey, but acetylation occurred in vitro in rabbit or monkey liver homogenates. 8. These findings are discussed.     

Analogues of 1-(3,10-dibromo-8-chloro-6,11-dihydro-5H-benzo-[5,6]-cyclohepta [1,2-b]pyridin-11-yl)piperidine as inhibitors of farnesyl protein transferase.

The synthesis of several 4-pyridylacetyl N-oxide derivatives of 4-(3-bromo-6,11-dihydro-5H-benzo[5,6]-cyclohepta[1,2-b]-pyridin-11-yl)pi perazine/piperidine 3 is described. This study was aimed at identifying fomesyl protein transferase (FPT) inhibitors in these two series of tricycles containing different phenyl ring substituents. The in vitro activity profile of the initial group of compounds 7a-7g led to the synthesis of the 8-methyl-10-methoxy and 8-methyl-10-bromo analogues 7i, 13i, and 13j. The 11R(-) enantiomers of these compounds were found to exhibit potent in vitro FPT inhibition activity.     

Tricyclic azepine derivatives: pyrimido[4,5-b]-1,4-benzoxazepines as a novel class of epidermal growth factor receptor kinase inhibitors

A novel class of pyrimido[4,5-b]-1,4-benzoxazepines is described as inhibitors of epidermal growth factor receptor (EGFR) tyrosine kinase. Two compounds display potent EGFR inhibitory activity of less than 1 microM in cellular phosphorylation assays (IC(50) 0.47-0.69 microM) and are highly selective against a small kinase panel. Such compounds demonstrate anti-EGFR activity within a class that is different from any known EGFR inhibitor scaffolds. They also provide a basis for the design of kinase inhibitors with the desired selectivity profile.     

Bicyclo[3,2,1]octanoid,neolignans from Aniba simulans

Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2R,3S,3aS)-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.     

Synthesis and in vitro antiproliferative activity of new 11-aminoalkylamino-substituted 5H- and 6H-indolo[2,3-b]quinolines; structure-activity relationships of neocryptolepines and 6-methyl congeners

The present report describes the synthesis and antiproliferative evaluation of certain 11-aminoalkylamino-substituted 5H- and 6H-indolo[2,3-b]quinolines and their methylated derivatives. These 5-Me- and 6-Me-indolo[2,3-b]quinoline derivatives 10-14, 20 were prepared by amination at the C-11 position of the 11-chloro-5-methyl-5H- and 11-chloro-6-methyl-6H-indolo[2,3-b]quinolines with different substituents on the quinoline ring. The 11-aminoalkylaminomethylated 23, the homologue of 11, was prepared from the same intermediate for a further SAR study. These intermediates are accessible from 4-substituted anilines or their N-methylated analogues and methyl indole-3-carboxylate as a counterpart. The in vitro antiproliferative assay indicated that the 5-methylated derivatives 10-14 are more cytotoxic than their respective 6-methylated 6H-indolo[2,3-b]quinoline derivatives 20. Among them, N-(3-aminopropyl)-2-bromo-5-methyl-5H-indolo[2,3-b]quinolin-11-amine 12f was the most cytotoxic with a mean IC(50) value of 0.12 μM against human leukemia MV4-11 cell line, and also exhibited selective cytotoxicities against A549 (lung cancer), HCT116 (colon cancer) cell lines and normal fibroblast BALB/3T3 with IC(50) values of 0.543, 0.274 and 0.869 μM, respectively. The binding constant of products 12f and 20f to salmon fish sperm DNA were also evaluated using UV-vis absorption spectroscopy, indicating intercalation binding with a constant of 2.93×10(5) and 3.28×10(5)Lmol(-1), respectively.     

Synthesis and acetylcholinesterase/butyrylcholinesterase inhibition activity of new tacrine-like analogues

The synthesis and preliminary results for acetylcholinesterase and butyrylcholinesterase inhibition activity of a series of pyrano[2,3-b]quinolines (2, 3) and benzonaphthyridines (5, 6) derivatives are described. These molecules are tacrine-like analogues which have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyrans and 6-amino-5-cyanopyridines]-3-carboxylates via Friedlander condensation with selected ketones. These compounds showed moderate acetylcholinesterase inhibition activity, the more potent (2e, 5b) being 6 times less active than tacrine. The butyrylcholinesterase activity of some of these molecules is also discussed.     

Synthesis and primary cytotoxicity evaluation of arylmethylenenaphthofuranones derivatives

New series of 2(or 3)-arylmethylenenaphtho[2,1-b]furan-3(or 2)-ones were synthesized, characterized and tested for anticancer properties in vitro. The target compounds were prepared by Knoevenagel coupling between the naphthofuranones 3, 28-30 and formyl derivatives. 2-(4-Oxo-1-benzopyran-3-ylmethylene)naphtho[2,1-b]furan-3-one 36 was the most active compound (IC50 (L1210) = 1.6 microM). These compounds were also evaluated, in an independent manner, as inhibitors of Src protein tyrosine kinase, but only minor activity was observed.     

Synthesis, and cytotoxic activity of some novel indolo[2,3-b]quinoline derivatives: DNA topoisomerase II inhibitors

A series of new 5H-indolo[2,3-b]quinoline derivatives bearing methoxy and methyl groups at C-2 and C-9 was synthesized (according to the modified Graebe-Ullmann reaction). These compounds were evaluated for their antimicrobial and cytotoxic activity and tested as inhibitors of DNA topoisomerase II. Lipophilic and calf thymus DNA binding properties of these compounds were also established. In the SAR studies we used quantum-mechanical methodology to analyze the molecular properties of the drugs. All of the 5H-indolo[2,3-b]quinolines tested were found to inhibit the growth of gram-positive bacteria and pathogenic fungi at MIC ranging between 2.0 and 6.0 microM. They showed also cytotoxic activity in vitro against several human cancer cell lines of different origin (ID50 varied from 0.6 to 1.4 microM), and stimulated the formation of topoisomerase-II-mediated pSP65 DNA cleavage at concentration between 0.2 and 0.5 microM. The most active indolo[2,3-b]quinolines which had the greatest contribution to the increase in the Tm of DNA displayed also the highest DNA binding constants and the highest cytotoxic activity. The differences in DNA binding properties and cytotoxic activity seem to be more related to steric than electrostatic effects.     

Effects of various radicinin analogs on pulse amplitude and arterial blood pressure

The action of some radicinin analogues on the pulse amplitude in urethane anesthetized rats has been studied. The compounds used are:2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione (I); 2,3-dihydro-2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione (II) 7,8-dihydro-2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione (III) 2,3,7,8-tetrahydro-2,7-dimethyl-4H,5H-pyrano[4,3-b]pyran-4,5-dione(IV); 2,3,7,8,4',8'-hexahydro-2,7-dimethyl-4H,5H-pyrano[4, 3-b]pyran-4,5-dione (V); 3-crotonyl-4-hydroxy-6-methyl-2H-pyran-2-one (VI); 3-hexanoyl-4-hydroxy-6-methyl-2H-pyran-2-one (VII); 3-hexanoyl-5,6-dihydro-4-hydroxy-6-methyl-2H-pyran-2-one (VIII). A clear increase in the pulse has been seen with the compounds (II), (V) and (VII) especially at the lowest doses, while a decrease in the pulse is caused by the compounds (I) and (VIII). The studied substances have no effects on systolic blood pressure in normotensive unanesthetized rats.     

Synthesis and biological evaluation of tetracyclic thienopyridones as antibacterial and antitumor agents

A facile synthesis of model 4-oxopyrido[3',2':4,5]thieno[3,2-b]indole-3-carboxylic acids 9a-e was achieved via Stille arylation of 2-chloro-3-nitro-4-oxothieno[2,3-b]pyridine-5-carboxylate and a subsequent microwave-assisted phosphite-mediated Cadogan reaction. The new compounds were tested for their in vitro antimicrobial and antiproliferative activity. Compounds 9a-c and 9e exhibited very high potency against Gram positive Bacillus subtilis and Bacillus megaterium at concentrations 0.000015-0.007 μg/mL. They also displayed excellent activity towards other Gram positive bacilli and staphylococci and Gram negative Haemophilus influenzae, being in most cases superior or equal to commercial fluoroquinolones. Both 9a and 9c were inhibitors of the DNA gyrase activity. As concerns antitumor properties, compounds 9b-e showed growth inhibition of MCF-7 breast tumor and A549 non-small cell lung cancer cells with IC(50) 1.6-2.8 μM and 2.6-6.9 μM, respectively, coupled with absence of cytotoxicity towards normal cells. These compounds are promising as dual acting chemotherapeutics.     

Inhibition of Src kinase activity by 7-ethynyl-4-phenylamino-3-quinolinecarbonitriles: identification of SKS-927

Of a series of 7-ethynyl-3-quinolinecarbonitriles, the most potent Src inhibitory activity was observed with 4-[(2,4-dichloro-5-methoxyphenyl)amino]-6-methoxy-7-[4-(4-methylpiperazin-1-yl)but-1-ynyl]-3-quinolinecarbonitrile (SKS-927). Variation of the solubilizing amine tail or removal of the methoxy group from either C-6 of the quinoline core or C-5 of the aniline headpiece led to reduced activity.     

Antiviral 2,5-disubstituted imidazo[4,5-c]pyridines: from anti-pestivirus to anti-hepatitis C virus activity

A novel class of inhibitors of the hepatitis C virus [substituted 2-(2-fluorophenyl)-5H-imidazo[4,5-c]pyridines] is described. Introduction of a fluorine in position 2 of the 2-phenyl substituent of the lead anti-pestivirus compound 1 (5-[(4-bromophenyl)methyl]-2-phenyl-5H-imidazo[4,5-c]pyridine) resulted in an analogue with selective activity against HCV in the subgenomic replicon system.     

The synthesis and vasopressin (AVP) antagonist activity of a novel series of N-aroyl-2,4,5,6-tetrahydropyrazolo[3,4-d]thieno[3,2-b]azepines

Synthesis and SAR of N-[4-[(4,5-dihydropyrazolo[3,4-d]thieno[3,2-b]azepin-6(2H)-y l)carbonyl]phenyl]benzamides as arginine vasopressin (AVP) receptor antagonists are discussed. Potent orally active AVP receptor antagonists are produced when the benzamide moiety contains a phenyl group at the 2-position. Similar analogues of 4,6,7,8-tetrahydro-5H-thieno[3,2-b]azepine and VPA-985 are reported.