Biopharmaceutic evaluation of novel anthelmintic (1H-benzimidazol-5(6)-yl)carboxamide derivatives

Benzimidazole 2-carbamates, such as albendazole (ABZ) and mebendazole (MBZ), used for the treatment of helmintic infections, have low aqueous solubility and poor bioavailability, both of which lead to high interindividual variability when used for human systemic helmintiosis; therefore, it is necessary to search for new anthelmintics with better biopharmaceutical properties. In the present study the solubility, pKa, logP and apparent permeability in the Caco-2 cells system of four novel anthelmintic (1H-benzimidazol-5(6)-yl)carboxamide derivatives (compounds 1-4) with a 2-methylthyo group were evaluated. Also the pharmacokinetic parameters of compound 1 which in previous studies showed activity similar to ABZ against T. spirallis, was evaluated in BALB/c mice, as a representative molecule of the series. The novel anthelmintics, showed better solubility than ABZ in aqueous acid pH and in organic solvents. The logP, P(app) and Caco-2 data indicate that the 4 derivatives are highly permeable drugs, but it is possible that an efflux system could be involved in the transport of these compounds. Plasma levels of compound 1 and its sulfoxide (compound 5) were high after the first 5 min. This fact strongly suggests that compound 1 is rapidly metabolized in the small intestine. On the other hand, the sulfone metabolite (compound 6) levels were lower than those of compound 5. The half life and mean residence time (MRT) of compound 1 and its main metabolites indicate that their elimination is very rapid. More studies in mammalian species are necessary in order to understand the pharmacokinetic behavior of these novel compounds.     

Synthesis and pharmacological evaluation of novel 1-(piperidin-4-yl)-1H-benzo[d]imidazol-2(3H)-one derivatives as potential antimicrobial agents

Novel compounds of biological interest were synthesized by in situ reduction of Schiff’s base of 5,6-dimethoxy indanone and 1-(piperidin-4-yl)-1H-benzo[d]imidazol-2(3H)-one in the presence of Ti(OiPr)₄ and NaBH₃CN. Further alkylation using different alkyl/aryl halides in the presence of NaH in DMF gave a series of novel compounds. A formation of newly synthesized compounds was confirmed on the basis of their spectral and elemental analysis. Further these compounds were screened for their antimicrobial activity and found to have promising antibacterial and antifungal activity.     

Synthesis, antibacterial, antifungal and anti-HIV activities of Schiff and Mannich bases derived from isatin derivatives and N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide.

Isatin, its 5-chloro and 5-bromo derivatives have been reacted with N-[4-(4'-chlorophenyl)thiazol-2-yl] thiosemicarbazide to form Schiff bases and the N-Mannich bases of these compounds were synthesized by reacting them with formaldehyde and three secondary amines. Their chemical structures have been confirmed by means of IR, 1H-NMR data and by elemental analysis. Investigation of antimicrobial activity of compounds was done by agar dilution method against 28 pathogenic bacteria, 8 pathogenic fungi and anti-HIV activity against replication of HIV-1 (IIIB) in MT-4 cells. Among the compounds tested 1-[N,N-dimethylaminomethyl]-5-bromo isatin-3-{1'-[4"-(p-chlorophenyl) thiazol-2"-yl] thio semicarbazone} 10 showed the most favourable antimicrobial activity.     

Synthesis and antibacterial activity of N-[5-chlorobenzylthio-1,3,4-thiadiazol-2-yl] piperazinyl quinolone derivatives

A series ofN-[5-(chlorobenzylthio)-1,3,4-thiadiazol-2-yl] piperazinyl quinolone derivatives (4a-1) have been synthesized by reaction of piperazinyl quinolones with 5-chloro-2-(chloroben-zylthio)-1,3,4-thiadiazoles. Their structures were confirmed by elemental analysis, IR and NMR spectra. The antibacterial activities of4a-1 against a variety of Gram-positive and Gram-negative bacteria were determined. Several compounds showed a good antibacterial activity against Gram-positive bacteria among which, compound 4e with a 2-chlorobenzylthio moiety in ciprofloxacin derivative, exhibited high activities againstStaphylococcus aureus andStaphylococcus epidermidis (MIC=0.06 μg/mL). The structure-activity relationship (SAR) study revealed that the position of chlorine atom on benzyl moiety would dramatically affect the antibacterial activities of the synthesized compounds.     

Synthesis of substituted benzo[d]thiazol-2-ylcarbamates as potential anticonvulsants

A series of substituted benzo[d]thiazol-2-ylcarbamates 4a–g and 5a–g were synthesized and evaluated for anticonvulsant activity. The structures of the synthesized compounds were confirmed on the basis of their physical and spectral data. The compounds were evaluated for anticonvulsant activity using PTZ-induced convulsion and maximal electroshock models. The target compounds have shown significant activity in these models.     

Synthesis and antimicrobial activity of N-[4-(1,3-benzodithiol-2-yl)phenyl]-and N-[4-(4-aryl-1,3-dithiol-2-yl)phenyl]-substituted N-arylmethylamines

Methods for the synthesis of secondary aromatic amines containing 1,3-benzodithiol or 4-aryl-1,3-dithiol cycles have been developed. The antimicrobial activity of the synthesized compounds has been determined. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 10, pp. 28–29, October, 2006.     

Anti-anxiety effect of a novel 5-HT3 receptor antagonist N-(benzo[d]thiazol-2-yl)-3-ethoxyquinoxalin-2-carboxamide (6k) using battery tests for anxiety in mice

Objective:

To investigate the anti-anxiety activity of “6k”, a novel 5-hydroxytryptamine type 3 (5-HT₃) receptor antagonist in in mice.

Materials and Methods:

Anti-anxiety activity of “6k” (1, 2, and 4 mg/kg, intraperitoneally (i.p.)) was evaluated in mice by behavioral tests such as elevated plus maze (EPM), open field test (OFT), light-dark box (L&D), and hole board test (HBT). Diazepam (2 mg/kg, i.p.) served as reference standard.

Results:

“6k” significantly (P < 0.05) increased the time and entries in open arm in EPM as compared to vehicle control group. Further, “6k” significantly (P < 0.05) increased the central and peripheral ambulation along with rearings and time in central area; whereas, reduced the fecal pellets in OFT as compared to vehicle control group. There was significant (P < 0.05) reduction in the latency to enter dark chamber; whereas, increased number of crossings and time in light chamber in L&D aversion test by treatment with “6k” as compared to vehicle control group. In HBT, “6k” significantly (P < 0.05) increased the number of head dipping and squares crossed; whereas, reduced the latency for first head dip and number of fecal pellets as compared to vehicle control group.

Conclusion:

A novel 5-HT₃ receptor antagonist has anti-anxiety action.KEY WORDS: 5-HT₃ antagonist, anxiety, elevated plus maze, open field test, hole board test     

Synthesis and structure-activity relationships of N-{3-[2-(4-alkoxyphenoxy)thiazol-5-yl]-1- methylprop-2-ynyl}carboxy derivatives as selective acetyl-CoA carboxylase 2 inhibitors

A structurally novel acetyl-CoA carboxylase (ACC) inhibitor is identified from high-throughput screening. A preliminary structure-activity relationship study led to the discovery of potent dual ACC1/ACC2 and ACC2 selective inhibitors against human recombinant ACC1 and ACC2. Selective ACC2 inhibitors exhibited IC50<20 nM and >1000-fold selectivity against ACC1. (S)-Enantiomer 9p exhibited high ACC2 activity and lowered muscle malonyl-CoA dose-dependently in acute rodent studies, whereas (R)-enantiomer 9o was weak and had no effect on the malonyl-CoA level.     

Synthesis and antimicrobial activity of [2-[2-(N,N-disubstituted thiocarbamoyl-sulfanyl)-acylamino] thiazol-4-yl]acetic acid ethyl esters

[2-[2-(N, N-Disubstituted thiocarbamoyl-sulfanyl)acylamino ]thiazol-4-yl]acetic acid ethyl esters (3a-x) were synthesized by the reaction of potassium salts of N, N-disubstituted dithiocarbamoic acids with [2-(2-chloroalkanoyl)amino-thiazol-4-yl]acetic acid ethyl esters. The structures of the synthesized compounds were confirmed by elemental analyses, UV, IR, (1)H-NMR, and EI mass spectral data. The antimicrobial activities of all the compounds were investigated by microbroth dilution technique using Mueller-Hinton broth and Mueller-Hinton agar. In this study, Staphylococcus aureus ATCC 6538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa AT CC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis ATCC 14153 and Candida albicans ATCC10231 were used as test microorganisms. Among the tested compounds 3a, d, e, f, h, k, w activity against S. epidermidis ATCC 12228 (MIC: 156 mg/L, 78 mg/L, 62.5 mg/L, 78 mg/L, 62.5 mg/L, 312 mg/L, 250 mg/L, respectively), compound 3d had some activity against S. aureus ATCC 6538 (MIC: 156 mg/L) and C. albicans ATCC 10231(MIC: 156 mg/L). Compounds 3l, 3x also evaluated for antituberculosis activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system and BACTEC 12B medium. The preliminary results indicated that all of the tested compounds were inactive against the test organism.     

Synthesis and pharmacological evaluation of perhydropyrrolo [3,4-c]pyridine derivatives

Several N,N'-bis-alkyl-perhydropyrrolo[3,4-c]pyridines 4 and the corresponding bis-quaternary derivatives 5 have been prepared through standard methods starting from the bicyclic dilactam 2. Compounds 4 and 5 were evaluated for their inhibitory properties against acetylcholine (ACh), 1,1-dimethylphenyl piperazinium iodide (DMPP), 5-hydroxytryptamine (5-HT) and histamine (H1), and the guinea pig isolated ileum. Pharmacological data indicated that the strongest anticholinergic activity was shown by the dibenzyl amine 4 g, which among the tested molecules presented also a rather potent effect at the ganglia level, resulting about three times more potent than hexamethonium as ganglionic blocking agent. The preliminary SAR coming from the analysis of the pharmacological results are presented and discussed.     

Synthesis and pharmacological evaluation of some N-[pyridyl(phenyl)carbonylamino]methyl-1,2,3,6-tetrahydropyrid ines.

Reaction of some picolines 5 with 1-chloro-2,4-dinitrobenzene (6) in acetone furnished methyl-substituted 2,4-dinitrophenylpyridinium chlorides 7. Further reaction with phenyl(pyridyl)carbonyl hydrazides 8 at room temperature furnished isolable 2,4-dinitroanilino derivatives 9, which were then refluxed in a water:dioxane mixture (1:4, v/v) to furnish the methyl-substituted phenyl(pyridyl)carbonyl iminopyridinium ylides 10. Reduction of the ylides with NaBH4 finally gave rise to the desired methyl-substituted phenyl(pyridyl)carbonylamino-1,2,3,6-tetrahydropyridines 11. The anti-inflammatory activities of 11a-11l were determined with the carrageenan-soaked sponge model of inflammation in Sprague-Dawley rats, and the analgesic effects of these derivatives were assessed by suppression of acetic acid-induced writhing in male Swiss albino mice. All compounds tested showed moderate to good anti-inflammatory and analgesic effects compared with indomethacin. Compound 11k was the most active analgesic, and 11h was the most effective anti-inflammatory agent among the methyl-substituted tetrahydropyridines.     

Synthesis and biological evaluation of 6-(alkyn-1-yl)furo[2,3-d]pyrimidin-2(3H)-one base and nucleoside derivatives

Derivatives of the 2'-deoxynucleoside of furo[2,3-d]pyrimidin-2(3H)-one with long-chain alkyl (or 4-alkylphenyl) substituents at C6 exhibit remarkable anti-VZV (varicella-zoster virus) potency and selectivity, and analogous 2',3'-dideoxynucleoside derivatives show anti-HCMV (human cytomegalovirus) activity. We now report a synthetic approach that enables the preparation of long-chain 6-(alkyn-1-yl)furo[2,3-d]pyrimidin-2(3H)-ones in which the rodlike acetylene spacer replaces the 4-substituted-phenyl ring at C6. Analogues with methyl, beta-d-ribofuranosyl, beta-d-arabinofuranosyl, and 2-deoxy-beta-d-erythro-pentofuranosyl substituents at N3 have been prepared. Long-chain derivatives at C6 in the 2'-deoxynucleoside series showed virus-encoded nucleoside kinase-sensitive anti-VZV activity. Surprisingly, 3-methyl-6-(octyn-1-yl)furo[2,3-d]pyrimidin-2(3H)-one (prepared as a negative anti-VZV test control) exhibited anti-HCMV activity, which supports the possibility of development of non-nucleoside anti-HCMV agents originating from uncomplicated derivatives of such bicyclic ring systems.     

Synthesis, in-vitro anticancer screening and radiosensitizing evaluation of some new N-(quinoxalin-2-yl)benzenesulfonamide derivatives

The objective of this work is to synthesize and investigate the anticancer activity of a new series of sulfaquinoxaline derivatives by incorporating biologically active moieties (thiourethane, thiazole, imidazole, imidazopyrimidine, imidazopyrimido-pyrimidine, thienopyrimidine, benzopyrimidinone, benzothiazole, thiazole and pyridine moieties). All the newly synthesized compounds were evaluated for their in-vitro anticancer activity against human liver cell line (HEPG2). All the tested compounds showed comparable activity to that of the reference drug 5-fluorouracil (IC50=40?μM), and the most potent compounds were found to be compounds 4 and 17 (IC50=4.29 and 11.27?μM, respectively). On the other hand, the most potent compounds 4 and 17 were evaluated as radiosensitizing agents.     

Synthesis and microbiological activity of some novel N-[2-(p-substitutedphenyl)-5-benzoxazolyl]-cyclohexyl carboxamide, -cyclohexyl acetamide and -cyclohexyl propionamide derivatives

The synthesis and microbiological activity of a new series of N-[2-(p-substitutedphenyl)-5-benzoxazolyl]-cyclohexyl carboxamide, -cyclohexyl acetamide and -cyclohexyl propionamide derivatives (4-11) is described. The in vitro microbiological activity of the compounds was determined against gram-positive, gram-negative bacteria and the yeast Candida albicans in comparison with standard drugs. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity against the tested microorganisms.     

1-甲基-β-咔啉-3-甲酰甘氨酸的合成

目的:合成1-甲基-β-咔啉-3-甲酰甘氨酸.方法:以L-色氨酸为原料,先后经Pictet-Spengler缩合、甲基化、芳构化、水解、与甘氨基酸酯偶联、水解共6步反应,生成目标化合物.结果:本实验Pictet-Spengler缩合、芳构化和偶联三步反应的收率分别为95%,65%和37%.在10,1和0.1μmol·L-1浓度下,1-甲基-β-咔啉-3-甲酰甘氨酸苄酯对MCF-7肿瘤细胞株的抑制率分别为61.50%,12.40%和7 24%.结论:本合成路线基本满足了目标化合物合成的实用化要求,1-甲基-β-咔啉-3-甲酰氨基酸及酯作为抗肿瘤结构显示了潜在前景.     

Histamine H1 receptor ligands: part II. Synthesis and in vitro pharmacology of 2-[2-(phenylamino)thiazol-4-yl]ethanamine and 2-(2-benzhydrylthiazol-4-yl)ethanamine derivatives

New 2-[2-(phenylamino)thiazol-4-yl]ethanamine and 2-(2-benzhydrylthiazol-4-yl)ethanamine derivatives were prepared and tested in vitro as H1 receptor antagonists. The compounds with 2-phenylamino substitution with meta-halide substituents at the phenyl ring, showed weak H1-antagonistic activity (pA2: 4.62-5.04) and this activity was completely lost in the case of meta-methyl substituent (pA2 < 4). When the phenylamino group was replaced by benzhydryl groups of classic antihistamines, the resulting compounds exhibited slightly improved H1-antagonistic activity (at the meta-position pA2: 6.38-6.15; at the para-position pA2: 6.04-5.87).     

Synthesis and cytotoxic evaluation of N-(4-methoxy-1H-benzo[d]imidazol-7-yl)-arylsulfonamide and N-aryl-(4-methoxy-1H-benzo[d]imidazol)-7-sulfonamide analogs of combretastatin A-4

Two series of novel benzoimidazole sulfonamides as combretastatin A-4 analogs were synthesized. The cytotoxicities of the title compounds were evaluated against five different cancer cell lines. Among the tested compounds, four compounds displayed cytotoxicities against the HCT8 cell line. Compound 6a has shown the strongest potency against the tested human tumor cell lines with an IC?? value ranging from submicromolar to micromolar level.     

Synthesis, physicochemical and anticonvulsant properties of new N-(pyridine-2-yl) derivatives of 2-azaspiro[4.4]nonane and [4.5]decane-1,3-dione. Part II

A series of N-(pyridine-2-yl) derivatives of 2-azaspiro[4.4]nonane- (1a-e), 2-azaspiro[4.5]decane- (2a-e) and 6-methyl-2-azaspiro[4.5]decane-1,3-dione (3a-e) were synthesized and tested for their anticonvulsant activity in the maximum electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure threshold tests. To explain the possible mechanism of action, the most active compounds N-(3-methylpyridine-2-yl)-2-azaspiro[4.4]nonane-1,3-dione (1b), N-(3-methylpyridine-2-yl)-2-azaspiro[4.5]decane-1,3-dione (2b), N-(4-methylpyridine-2-yl)-2-azaspiro[4.5]decane-1,3-dione (2c), and N-(3-methylpyridine-2-yl)-6-methyl-2-azaspiro[4.5]decane-1,3-dione (3b) were tested in vitro for their influence on voltage-sensitive calcium channel receptors, however, they revealed low affinities. For all synthesized compounds the lipophilicity was determined by use of RP-TLC method. The correlation between the lipophilicity and anticonvulsant activity was obtained--the higher the lipophilicity the stronger the anticonvulsant efficacy.