Synthesis and antimicrobial activity of new 4-thiazolidinone derivatives containing 2-amino-6-methoxybenzothiazole

A novel series of Schiff bases 5a–j and 4-thiazolidinones 6a–j have been prepared from the building blocks 2-chloro pyridine-3-carboxylic acid [1] and 2-amino-6-methoxy-benzothiazole [2]. All of the synthesized compounds have been confirmed by elemental analyses, IR, ¹H NMR and ¹³C NMR spectral data. These newly synthesized compounds were screened for their antimicrobial activity. Variable and modest activity was observed against the investigated strains of bacteria and fungi, however, compound 6h revealed significant antibacterial activity against Escherichia coli. Compounds 1, 2, 3, 5c, 5g and 5h, on the other hand, revealed potent antifungal activity against Candida albicans compared to the reference drug greseofulvin.     

Synthesis and antimicrobial activity of some new hydrazones of 4-fluorobenzoic acid hydrazide and 3-acetyl-2,5-disubstituted-1,3,4-oxadiazolines

A series of hydrazide hydrazones and 1,3,4-oxadiazolines of 4-fluorobenzoic acid hydrazide were prepared and evaluated as potential antimicrobial agents and were tested for their antibacterial and antifungal activities against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. From these compounds, 4-fluorobenzoic acid[(5-nitro-2-furanyl)methylene]hydrazide (1a) showed equal activity with ceftriaxone against S. aureus. In addition, the MIC values of compounds 1c, 1d and 2a for the same strain were in the range of those reported for ceftriaxone according to NCCLS 1997.     

New amides of 5-(4-chlorobenzoyl)aminoorotic acid: their synthesis and biological activity

The synthesis and in-vitro biological evaluation of the amide series 4 of 5-(4-chlorobenzoyl)aminoorotic acid 2 are presented. The biological properties of a few 5-(4-chlorobenzoyl)amino-2,6-dihydroxy-N-substituted-4-pyrimidinecarboxamide derivatives 4 tested here were compared with those of the isosteric isothiazole derivative MR-2/94 (5-(4-chlorobenzoyl)amino-N-(4-chlorophenyl)-3-methyl-4-isothiazolecarboxamide), which possesses a strong immunosuppressive and anti-inflammatory activity [1, 2], It must be suggested that replacement of the isothiazole by a pyrimidine core ring system resulted in considerable lowering of the anti-inflammatory and immunotropic actions of the obtained amides. Physicochemical properties of 2-(4-chlorophenyl)-6,8-dihydroxy-4H-pyrimido[5,4-d]-1,3-oxazin-4-on 3 are also briefly described.     

Synthesis,characterization and biological applications of novel Schiff bases of 2-(trifluoromethoxy) aniline

A series of five new Schiff bases (1–5) were synthesized by reacting 2-(trifluoromethoxy) aniline with different aromatic aldehydes. The Schiff base compounds were characterized by spectroscopic and analytical methods. Crystal structure of one new compound was also reported. The pharmacological properties, including antibacterial (14 bacterial species), antifungal (7 strains),antimalarial, anti-trypanosomal and anti-HIV activities of the compounds, were investigated. Cytotoxicity of the tested compounds was evaluated against human cervix adernocarcinoma cells (HeLa). Bacterial minimum inhibitory concentration (MIC) results by broth microdilution method showed that Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Proteus vulgaris, Klebsiella oxytoc and Klebsiella pneumonia were more sensitive in the presence of tested compounds with an MIC value of 15.6 µg/mL. All the tested compounds showed good to moderate activity against fungi. The sensitivity of Aspergillus fumigatus was higher than other strains with aminimum cell death concentration (MFC) of 15.6 µg/mL. Compound 1 showed greater antimalarial and anti-trypanosomal properties with very low to no cytotoxic effects against HeLa cells as compared with compound 5, while other compounds exhibited poor activity. Compounds 1–5 demonstrated good activity against HIV type-1. These Schiff base compounds could be used as good antimicrobial agents.     

4-氨基-5-氯-2-乙氧基苯甲酸的合成

目的合成4-氨基-5-氯-2-乙氧基苯甲酸。方法以对氨基水杨酸钠为原料,经酸化、甲酯化、乙酰化、乙基化、氯代、水解等六步反应得到枸橼酸莫沙必利的主要中间体4-氨基-5-氯-2-乙基苯甲酸。结果与结论本合成工艺提高了收率,降低了成本,更适合工业化生产,本工艺总收率为62.4%。     

Antibacterial activity of dipeptide constructs of acetylsalicylic acid and nicotinic acid

Two dipeptide drugs are synthesized utilizing an acetylsalicylic acid or nicotinic acid molecule for the framework. A D-alanine-D-alanine dipeptide moiety is attached to the carbonyl carbon of acetylsalicylic acid (I) and nicotinic acid (II). Dipeptide derivatives (I) and (II) showed significant reduction of Escherichia coli (E. coli) bacterial growth and colony-forming units. A mixture of (I) and (II) induced growth inhibition of 8%, 17.5%, 28%, and 42.5% at concentrations of 100, 200, 300, and 400 μg/mL, respectively. Ampicillin demonstrated much less growth inhibition of this penicillin-resistant E. coli bacteria. Derivatives (I) and (II) showed significant reduction of colony-forming units at concentrations higher than 200 μg/mL, whereas ampicillin showed no significant affect on colony-forming units. Both (I) and (II) produced no violations of the Rule of 5, indicating favorable characteristics for bioavailability. Molecular properties were determined and showed (I) to have a Log Kow of -0.22 with aqueous solubility of 683.8 mg/L, whereas (II) had a Log Kow of -1.00 and aqueous solubility of 6859 mg/L. A mixture of the parent compounds acetyl salicylic acid and nicotinic acid demonstrated some antibacterial activity.     

Synthesis,characterization and anticancer activity of certain 3-{4-(5-mercapto-1,3,4-oxadiazole-2-yl)phenylimino}indolin-2-one derivatives

A series of 5- or 7-substituted 3-{4-(5-mercapto-1,3,4-oxadiazol-2-yl)phenylimino}-indolin-2-one derivatives were synthesized by treating 5-(4-aminophenyl)-1,3,4-oxadiazole-2-thiol with different isatin derivatives. The newly synthesized compounds were characterized on the basis of spectral (FT-IR, ¹H NMR, MS) analyses. All the synthesized derivatives were screened for anticancer activity against HeLa cancer cell lines using MTT assay. All the synthetic compounds produced a dose dependant inhibition of growth of the cells. The IC₅₀ values of all the synthetic test compounds were found between 10.64 and 33.62 μM. The potency (IC₅₀ values) of anticancer activity of compounds VIb–d was comparable with that of known anticancer agent, Cisplatin. Among the synthesized 2-indolinones, compounds VIb–d with halogen atom (electron withdrawing groups) at C5 position showed the most potent activity. These results indicate that C5 substituted derivatives may be useful leads for anticancer drug development in the future.     

Synthesis and evaluation for biological activity of 3-alkyl and 3-halogenoalkyl-quinoxalin-2-ones variously substituted. Part 4

A new series of 3-isopropyl-, 3-trifluoromethyl- and 3-bromomethylquinoxaline-2-ones variously substituted on the benzo-moiety were synthesized and submitted to a preliminary in vitro evaluation for antibacterial, antifungal and anti-HIV activities. Furthermore, all compounds were also tested for cytotoxicity. Results of the screening showed that compound 10 exhibits moderate antimicrobial activity against Staphylococcus aureus (MIC = 33 microM), and that 25 and 26 showed interesting cytotoxicity versus mock-infected MT-4 cells. All the other compounds were inactive.     

Synthesis of 5- and 6-N-heterocyclic methylenebisphosphonate derivatives and evaluation of their cytogenetic activity in normal human lymphocyte cultures

Methods for the preparation of various aminomethylene bisphosphonates were developed. The required bisphosphonates were obtained by applying tetraethyl methylenebisphosphonate reagent to different types of oxazinones and the relevant Schiff base derivatives. Based on the prediction results (Pass program), we further estimated the sister chromatid exchange frequency and proliferation rate index values of human lymphocyte cultures after the administration of four newly synthesized bisphosphonates in order to evaluate their cytotoxic/cytostatic and possible antineoplastic potency. The results showed that all four bisphosphonates cause a dose-dependent increase in sister chromatid exchange frequency, followed by a decrease in proliferation rate index in both experiments compared to the control.     

Synthesis of 4-aminoantipyrine Schiff bases and their antimicrobial activities

Various compounds of 4-aminoantipyrine Schiff bases (M₁–M₁₂) were synthesized via a condensation reaction of 4-aminoantipyrine with different benzaldehydes through a conventional method of refluxing the mixture for 3–4 h. The synthesizedSchiff bases were characterized by using elemental analyses, FT-IR, UV-Vis, Mass, ¹H and ¹³C NMR spectroscopy. The antimicrobial activity of the synthesized Schiff bases was investigated against 12 bacterial strains(Mycobacterium smegmatis, Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Staphylococcus epidermidis, Klebsiella pneumonia, Escherichia coli, Enterobacter cloacae,Klebsiella oxytoca, Proteus vulgaris, Enterobacter aerogenes, and Pseudomonas aeruginosa), and antifungal activities were tested against seven fungal strains (Aspergillus flavus, Aspergillus carbonarious, Aspergillus parasiticus, Aspergillus fumigatus,Aspergillus niger, Fusarium verticillioides and Fusarium proliferatum). The antimicrobial activities of the synthesized compounds were compared with standard streptomycin and nalidixicacid. The results obtained from antibacterial assay indicated that M₁–M₁₂ inhibited potential growth of Proteus vulgaris with minimum inhibitory concentrations (MICs) ranging from 15.6–250 µg/mL compared with the standard nalidixic acid with an MIC of 500 µg/mL. Moreover, we could conclude that most of the tested compounds experienced mild to low activities at 15.6 µg/mL. Their activities could be attributed to their low concentrations.The antifungal analysis showed that the tested fungi were not sensitive to the prepared Schiff bases at the prepared concentration of 500 µg/mL. Therefore, we recommended further analysis on both cytotoxicity and minimum bactericidal concentration (MBC) to ascertain their potential effects against human cells.     

New conjugates of mycophenolic acid and their antiproliferative activity

The new conjugates of mycophenolic acid (MPA) were obtained in the reaction of N⁶-(ω-aminoalkyl)adenosines with MPA in the presence of EDCI as a coupling reagent. New compounds 4a–h were evaluated on leukemia cell line (Jurkat) and PBMC from healthy donors. Length of the linker influenced observed activity. The compound 4b possessing 1,3-diamine spacer exhibited the most promising results and can be considered to further investigations.     

Synthesis,characterization and biological activities of Schiff bases derived from 2-hydroxy-3-nitrobenzaldehyde

Four novel Schiff bases were synthesized by the condensation reaction of 2-hydroxyl-3-nitrobenzaldehyde with either benzothiazoles or benzimidazolamines. The compounds 1–4 were characterized by spectroscopic and analytical methods. The crystal structures of 6-methoxy-1,3-benzothiazol-2-amine and compound 2 are reported only. The 6-methoxy-1,3-benzothiazol-2-amine was found to crystallize in the orthorhombic crystal system in the space group Pbca, having eight molecules in the unit cell, while compound 2 was found to crystallize in the monoclinic crystal system in the space group P2₁/c.The biological activities of these compounds were investigated by evaluating their antibacterial, antifungal, antimalarial, anti-HIV and anti-trypanosomiasis activities. These compounds displayed very interesting antibacterial, antifungal, antimalarial, anti-trypanosomiasis, anti-HIV and low cytotoxicity activity against HeLa cells.     

烟酸缓释微丸的制备及释放度研究

目的制备12h烟酸缓释微丸并考察其释放度。方法采用离心造粒法制备烟酸载药素丸,以Surelease水分散体为包衣材料,进行包衣。考察了包衣液的处方因素以及释放介质对烟酸缓释微丸的释放度的影响。结果烟酸素丸圆整度良好,结果表明致孔剂可加快药物的释放,随着包衣厚度的增加,药物的释放逐渐变慢,释放介质中的钙离子浓度对烟酸缓释微丸释放没有显著影响,烟酸缓释微丸在强酸性条件下释放快,在较高pH值条件下没有明显的不同。结论模拟人体胃肠道条件下溶出,自制缓释烟酸微丸达到较好的缓释效果。     

Antituberculosis activity of hydrazones derived from 4-fluorobenzoic acid hydrazide

A series of substitututed methylene/ethylene 4-fluorophenylhydrazide derivatives (3a–p) was synthesized with the aim of evaluating their antimycobacterial activity toward a strain of Mycobacterium tuberculosis H37Rv. Their chemical structures were confirmed by ¹H-nuclear magnetic resonance (NMR) and electrospray mass spectrometry (ES-MS) spectral data, and elemental analysis. The in vitro antimycobacterial evaluation was performed according to the Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF) antituberculosis drug discovery program. Compound 3a, 4-fluorobenzoic acid [(2,6-dichlorophenyl) methylene]hydrazide, showed the highest inhibitory activity of all the compounds under study.     

Reactions of some cinnamoyl benzofuran derivatives with activated nitriles and their biological activity

Several 4-cyano-1-benzofuranyl-1-butanone derivatives were synthesized and screened for potential antiinflammatory and analgesic activities. The effect of structural variation of these molecules on biological activities was systematically examined. Among these compounds V _a , V _c and VI _e were found to demonstrate a significant antiinflammatory effect. Compounds VI _e , V _a , I _d , I _b and VII _f were also significantly effective as analgesic ones.     

Safety and tolerability of prolonged-release nicotinic acid in statin-treated patients

ABSTRACT

Objective: To evaluate the safety and tolerability of prolonged-release nicotinic acid (Niaspan) added to statin therapy in patients at increased cardiovascular risk.

Methods: This was a 6-month, prospective, observa­tional, multicentre, open-label evaluation of prolonged-release nicotinic acid (maximum dose 2000?mg/day) in statin-treated patients with cardiovascular disease and/or type 2 diabetes. The primary endpoint was the safety and tolerability of prolonged-release nicotinic acid, with special regard to treatment-related adverse drug reactions (ADRs). Secondary endpoints were changes in lipids and 10-year cardiovascular risk (Prospective Cardiovascular Münster (PROCAM) score).

Results: The study population included 1053 patients: 50% had hypertension, diabetes and/or metabolic syndrome (National Cholesterol Education Program/Adult Treatment Panel III criteria) and 80% had cardiovascular disease. Flushing (mostly mild or moderate) occurred in 430 patients (40.8%). Other ADRs occurred in 125 patients (12.5%), most commonly pruritus (2.7%), gastro­intestinal symptoms (3.8%) and nervous system-related complaints (3.8%). Serious ADRs were uncommon (0.6%). All patients recovered completely from these ADRs after treatment discontinuation. In total, 11.1% of the patients discontinued study medication for flushing and 8.4% for other ADRs. There was no evidence of hepatotoxicity or myopathy. New-onset hyperglycaemia was negligible. Overall tolerability of prolonged-release nicotinic acid treatment (n = 734 patients at closeout) was ‘very good’ in 130 (17.7%), ‘good’ in 262 (35.7%), and ‘acceptable’ in 144 (19.6%) patients. High-density lipoprotein (HDL) cholesterol increased by 23%, triglycerides decreased by 15% and LDL-C decreased by 4%.

Conclusions: Prolonged-release nicotinic acid was safe and generally well tolerated and effective in combination with statin therapy in patients at high risk of cardio­vascular events, with a side-effect profile consistent with previous clinical experience.     

Lipoic acid - biological activity and therapeutic potential

α-Lipoic acid (LA; 5-(1,2-dithiolan-3-yl)pentanoic acid) was originally isolated from bovine liver by Reed et al. in 1951. LA was once considered a vitamin. Subsequently, it was found that LA is not a vitamin and is synthesized by plants and animals. LA is covalently bound to the ε-amino group of lysine residues and functions as a cofactor for mitochondrial enzymes by catalyzing the oxidative decarboxylation of pyruvate, α-ketoglutarate and branched-chain α-keto acids. LA and its reduced form - dihydrolipoic acid (DHLA), meet all the criteria for an ideal antioxidant because they can easily quench radicals, can chelate metals, have an amphiphlic character and they do not exhibit any serious side effects. They interact with other antioxidants and can regenerate them. For this reason, LA is called an antioxidant of antioxidants. LA has an influence on the second messenger nuclear factor κB (NF-κB) and attenuates the release of free radicals and cytotoxic cytokines. The therapeutic action of LA is based on its antioxidant properties. Current studies support its use in the ancillary treatment of many diseases, such as diabetes, cardiovascular, neurodegenerative, autoimmune diseases, cancer and AIDS. This review was undertaken to gather the most recent information regarding the therapeutic properties of LA and its possible utility in disease treatment.     

New 4-thiazolidinones from 5-ethyl pyridine-2-ethanol: their antibacterial,antifungal, and antitubercular activity

New thiazolidinones 5a–o were prepared from Schiff base 4a–o and thioglycolic acid in the presence of ZnCl₂ from 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, ¹H NMR ¹³C NMR, and mass spectral data. All the compounds were screened against different strains of bacteria and fungi. Compounds 4e, 4n, 4m, 4o, 5e, 5f, 5j, and 5m possessed very good activity against bacterial and fungal species. These active compounds impelled us to study their antitubercular activity. Schiff base 4n and 4e showed M. tuberculosis MIC value 25 and 62.5 μg/ml, respectively. Thiazolidinone 5m displayed M. tuberculosis MIC at 25 μg/ml, which is better antitubercular activity compared with rifampicin.     

Synthesis of 2-hydrazolyl-4-thiazolidinones based on multicomponent reactions and biological evaluation against Trypanosoma Cruzi

A series of 18 novel 2-hydrazolyl-4-thiazolidinones-5-carboxylic acids, amides and 5,6-α,β-unsaturated esters were synthesized, and their in vitro activity on cruzipain and T. cruzi epimastigotes was determined. Some agents show activity at 37 μm concentration in the enzyme assay. Computational tools and docking were used to correlate the biological response with the physicochemical parameters of the compounds and their cruzipain inhibitory effects.