High-performance liquid chromatographic assay for the determination of novel triazole antifungal agents in tissue. Application to tissue distribution studies

A simple and rugged reversed-phase high-performance liquid chromatographic method with ultraviolet absorbance detection at 263 nm was developed and validated for the analysis of novel triazole antifungal agents SYN-2869 and its derivatives in tissues. The method involved homogenization with 0.01 M phosphate buffer (pH 7.8) for lung, brain and spleen tissues. The liver and kidneys were homogenized with acetonitrile:acetone (1:1). The plasma proteins were precipitated with ice-cold acetonitrile and supernatent was evaporated to dryness. The reconstituted samples were injected onto an HPLC system. SYN-2869 was separated from the matrix components on a symmetry C(18) column using a aqueous mobile phase of acetonitrile and water with a flow rate of 1 mL/min. A step gradient of 40-80% acetonitrile eluted SYN-2869 and the internal standard (SYN-2506). The linear range was 0.5-10 microgram/g (r(2) > 0.99). The limit of quantitation was 0.5 microgram/g. The inter-day precision and accuracy for SYN 2869 standard concentration were from 2.6 to 7.4% and from -1.56 to +3.29%, respectively. The method was applied to tissue samples collected from single intravenous administration to mice to evaluate the distribution of these novel antifungal agents to different tissues.     

Structure elucidation of three isomeric metabolites of SYN-2836, a novel antifungal agent, in dogs via liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry methodologies.

This paper presents liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) approaches for the rapid characterization of three urinary isomeric metabolites and their two precursor metabolites of SYN-2836, a novel antifungal agent, in dogs administered multiple oral doses of the agent (30 mg kg(-1) day(-1)). A collection of correlative data regarding the SYN-2836 metabolites was obtained by LC/MS and LC/MS/MS performed under complementary conditions such as the columns (C(18) vs cyano type), the mobile phase systems (acetonitrile-water-formic acid vs acetonitrile-water-ammonium acetate) and the electrospray ionization modes (positive vs negative). Metabolite identification was accomplished based on not only the LC/MS/MS data (product ion spectra) but also the LC/MS data indicating chromatographic behaviors of the metabolites. SYN-2836 and SYN-2869, an analog of the former, showed almost the same metabolic pathways following the same multiple-dose administration of the individual agents to the dogs. Therefore, correlation analysis in product ion spectra between corresponding metabolites of SYN-2836 and SYN-2869, and also in metabolic pathways between the two agents, was strategically used to facilitate the identification of the SYN-2836 (and SYN-2869 if necessary) metabolites. For the reason that various elucidation strategies were used complementarily, the chemical structures of the metabolites were unambiguously attained and the isomeric metabolites were explicitly differentiated without the use of other analytical methods. The methodologies used in this study may be applicable to metabolite screening of several structurally related agents simultaneously, promoting lead finding and optimization of drug candidates using a metabolism-based approach.     

Synthesis of novel selenium and tellurium-containing tetrazoles: a class of chalcogen compounds with antifungal activity

We describe herein the synthesis and antifungal activity of new 5-arylchalcogenoalkyl-1H-tetrazoles 4. Arylchalcogenoalkyl-1H-tetrazoles 4 have been synthesized in high yields by reaction of arylchalcogenolate anions with chloronitriles 2, and subsequent [2+3] cycloaddition of resulting arylchalcogenoalkylnitriles 3 with sodium azide by zinc catalysis in aqueous solution. The obtained compound 4a was screened for antifungal activity and presented inhibitory property against seven fungal strains. This protocol is an efficient method to produce new selenium–nitrogen compounds with antifungal activity.     

Total synthesis and structure–activity relationships of caspofungin-like macrocyclic antifungal lipopeptides

The echinocandins represent a well-known class of macrocyclic antifungal lipopeptides that can be used for treatment of invasive fungal infections. Due to their complex chemical structures and synthetic difficulties, the structure–activity relationships (SARs) of them are still limited. A total synthetic approach was developed to synthesize structurally diverse caspofungin-like antifungal cyclic lipopeptides, allowing for systemically investigating their SARs. Most of the designed cyclic lipopeptides showed potent antifungal activities with broad spectrum. In particular, several compounds (e.g., 30a, 30e–h, 31a–d, 32c, and 33a,b) were more active in vitro against Candida albicans or Aspergillus fumigatus than caspofungin. The findings in this work indicated that the ‘left’ tripeptide segment of cyclic lipopeptide scaffold might be suitable for a hydrophilic structural motif, whereas the ‘right’ lipotripeptide segment was preferred as a hydrophobic core. The alkoxy-naphthoyl was found to be optimal side chain and alkyl length could affect the SARs of alkoxy-aroyl side chains.     

Synthesis,characterization and microbiocidal studies of novel ionic liquid tagged Schiff bases

The synthesis of novel imidazolium ionic liquid, tagged Schiff, has been described. The synthesis was achieved in three steps from 2,4-dihydroxybenzaldehyde by selective alkylation with 1,3-dibromopropane, followed by reaction with 1-methylimidazole and Schiff base formation with aromatic amines. The compounds were evaluated for antibacterial and antifungal activities. The ionic liquid tagged Schiff base 4a showed the inhibition of both Gram positive and Gram negative bacteria. It also showed broad spectrum antifungal activity against all four tested fungi; however, 4f showed highest antifungal activity against A. niger.     

Synthesis and antimicrobial activities of some novel 1,2,4-triazole derivatives

In the present investigation, a series of new Schiff bases 4a–f were synthesized by the condensation of N-[(4-amino-5-sulfanyl-4H-1,2,4-triazol-3-yl)methyl]-4-substituted-benzamides 3a–b with various substituted aromatic aldehydes in ethanol–dioxane mixture using catalytic amount of sulfuric acid. The starting materials 3a–b were in turn synthesized by the fusion of benzoyl glycine/substituted benzoylglycine with thiocarbohydrazide. Newly synthesized compounds were characterized by IR, NMR, mass spectra and elemental analyses. All the compounds were evaluated for their antibacterial and antifungal activity using the Minimum Inhibition Concentration (MIC) method by serial dilution technique. Few of the compounds were found to be biologically active.     

Synthesis and biological activity of some fluorinated arylhydrazotriazoles

Potential biologically active derivatives of arylhydrazotriazole (3a–l) were prepared by the condensation reaction of diazonium salts using various aromatic amines (1a–l) and 1-(2,4-difluorophenyl)-2-(1H-1,2,4-triazol-1-yl) ethanones (2). The synthesized products were obtained in 75–85% yield. All the synthesized products were having good-excellent antifungal activity as compared with standard (Fluconazole and Ketoconazole) drugs.     

Synthesis of water-soluble nucleotide-calixarene conjugates and preliminary investigation of their in vitro DNA replication inhibitory activity

Calix[4]arenes bearing four thymine or adenine 2′-deoxynucleotide moieties have been synthesized and characterized by NMR and ESI-MS analysis. Due to their amphiphilic nature, the conjugates (2a and 2b) obtained tend to self-assemble in aqueous medium by stacking interactions. Their good water solubility makes 2a and 2b promising candidates for bioorganic applications. A preliminary study has provided evidence of their inhibitory activity toward the replication of a Penicillium digitatum DNA fragment via PCR (polymerase chain reaction).     

Synthesis of 5-phenyl-3-(10H-phenothiazinyl)-Δ2-cyclohexen-1-ones by conventional and microwave-assisted methods and their antifungal activity

A series of 5-phenyl-3-(10H-phenothiazinyl)-Δ²-cyclohexen-1-ones were prepared using conventional and microwave-assisted methods. The condensation between 3-phenyl-1-(10H-phenothiazinyl) prop-2-en-1-one derivatives (3a–g) and acetyl acetone yielded 5-phenyl-3-(10H-phenothiazinyl)-Δ²-cyclohexen-1-one derivatives (7a–g). The products were characterized by UV, IR, ¹H NMR, ¹³C NMR, 2D-NMR, MS, and elemental analysis. In vitro antifungal activity was carried out by zone of inhibition method against four species, namely Aspergillus niger, Candida albicans, Microsporum gypseum, and Aspergillus flavus. Compounds 7a and 7d showed good antifungal activity with zones of inhibition of 17 and 18 mm, respectively, and comparable with the standard substance, Bavinston, with 20 mm.     

Cleavage and some modifications of the 7-amide group of the cephamycins

The cleavage and some modifications of the 7-amide group of cephamycins are described. Cephamycin derivatives 16b, c which were synthesized from the naturally occurring cephamycin C (16a) were converted to the corresponding oxamic acid derivatives 17a, e respectively by the reaction with oxalyl chloride and successive treatment with water. The reaction of the oxamic acid 17a with diphenylcarbodiimide gave 7-aminocephamycinoic acid (7-ACMA) benzhydryl ester (21a) which was further converted to cefoxitin (21c). These compounds 17a, b, c, d, e, f thus obtained from cephamycin C appear to be favorable intermediates for the syntheses of cephamycin analogues such as cefmetazole (28c).     

Synthesis,crystal structure and 3D-QSAR studies of antifungal (bis-)1,2,4-triazole Mannich bases containing furyl and substituted piperazine moieties

This article exhibited the synthesis, crystal structure and 3D-QSAR studies of antifungal furyl- and piperazine- containing (bis-)1,2,4-triazole Mannich bases.     

Synthesis and antimicrobial activity of Schiff bases and 2-azetidinones derived from quinazolin-4(3H)-one

A series of 2-oxo-azetidinyl-quinazolin-4(3H)-ones 5a–k have been synthesized from Schiff bases 4a–k. Schiff bases were synthesized by the condensation reaction of compound 3 with substituted aromatic aldehydes. The benzoxazinone 2 was prepared by the cyclization reaction of acid chloride 1 with 5-bromo anthranilic acid. Further reaction of benzoxazinone 2 with hydrazine hydrate yielded compound 3. The structures of the synthesized compounds were elucidated on the basis of elemental analyses as well as IR and NMR spectral data. Schiff bases 4a–k and 2-azetidinones 5a–k were screened for antibacterial and antifungal activities in vitro. Compounds having chloro and methoxy groups exhibited good antimicrobial activity.     

Synthesis, characterization and antimicrobial activity of some new 1-(fluorobenzoyl)-3-(fluorophenyl)thioureas

Synthesis of a variety of new 1-(isomeric fluorobenzoyl)-3-(isomeric fluorophenyl)thioureas (1a-t) was accomplished in two steps. The synthetic route involves the reaction of equimolar quantities of isomeric fluorobenzoyl chlorides with potassium thiocyanate in anhydrous acetone to afford the corresponding isothiocyantes in situ, followed by treatment with equimolar quantities of isomeric fluoroanilines. All of the synthesized compounds (1a-t) were screened for their in vitro antibacterial activity using Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli, Pseudomonas aureginosa). The minimum inhibitory concentration (MIC) was also determined for the most active compounds. In vitro antifungal activity was also determined against the five fungal species (Rhizopus oryzae, Aspergillus tereus, Fusarium oxysporum, Aspergillus niger, Aspergillus fumigatus). In general, the antifungal activity of compounds was better than their antibacterial activity.     

Synthesis and biological evaluation of 4-thiazolidinone derivatives as antitubercular and antimicrobial agents

New series of N-[2-{2-(substitutedphenyl)-4-oxo-5-(substitutedbenzylidene)-1,3-thiazolidine}-iminoethyl]-2-amino-5-nitrothiazole, 5(a–m) have been synthesized from 2-amino-5-nitrothiazole as a starting material by conventional as well as microwave methods. All the synthesized compounds 4(a–m) were screened for their antibacterial and antifungal activities against some selected bacteria and fungi and antitubercular activity screened against Mycobacterium tuberculosis. The structure of all the synthesized compounds were confirmed by chemical and spectral analyses such as IR, ¹H NMR, ¹³C NMR and FAB-Mass.     

Substituent effect of fluorine atoms in the 2,4-difluorophenyl group on antifungal activity of CS-758

CS-758 is a novel triazole antifungal agent. To ascertain the effect of the fluorine atoms in the 2,4-difluorophenyl group, a series of compounds, 12a–12d, which have fluorine atom(s) in different positions on the benzene ring, were synthesized, and the minimum inhibitory concentrations (MICs) of this series of compounds were determined. All the compounds, including CS-758, exhibited excellent MICs against Candida, Aspergillus, and Cryptococcus species. Among them, the compounds having a fluorine atom in the 2-position on the benzene ring (12a, 12c, 12d, and CS-758) showed stronger antifungal activity particularly against Aspergillus species. The MICs of these compounds surpassed those of fluconazole and itraconazole against Candida, Aspergillus, and Cryptococcus species.     

Novel indan-1,3-dione derivatives: Design,green synthesis,effect against tomato damping-off disease caused by Fusarium oxysporum and in silico molecular docking study

An effective method for synthesizing series of twenty-two new compounds 1, 2a,b, 3, 4a,b, 5a-e, 7, 8, 9, 10, 12, 13a-d, 15a,b was performed starting from reaction of 1,2,3-indenetrione thiourea, and ethyl cyanoacetate under microwave irradiation and / or 2-(1,3-dioxo-1H-inden-2(3H)-ylidene) hydrazine carbothioamide with acetic anhydride. Chemical structure of the obtained products has been established by spectroscopic techniques including FTIR, ¹H NMR, ¹³C NMR, DEPT-135, and mass spectroscopy. The designed new compounds have been successfully examined in-vitro for their antifungal activities. The relation between the structure of the synthesized compounds and their activity against tomato damping-off disease caused by Fusarium oxysporum fungi was studied and favourable results were obtained. The antifungal studies indicated that compounds 1, 7, 4a and 5a-d exerted the highest antifungal activities, while 3 and 4b recorded the lowest effect. The obtained results confirmed the possibility of the application of ethyl 6′-amino-1,3-dioxo-2′-thioxo-1,2′,3,3′-tetrahydro-1′H-spiro[indene-2,4′-pyrimidine]-5′-carboxylate 1 as a new effective regulator of the vegetative growth of tomatoes. The molecular docking analysis was performed within succinate dehydrogenase (SDH) as a target enzyme in order to rationalize the promising findings obtained for the active compounds 1, 2a,b, 5a-d, 7, 8, 9, 10, 12, and 13a.     

Steroide—XL: 16,17-azido- und 16,17-aminoalkohole des östra-1,3,5(10)-trien-3-methyläthers

The four epimeric azido alcohols of estra-1,3,5(10)-trien-3-methyl ether with nitrogen at C-16 and oxygen at C-17 were prepared by the following reactions: cleavage of the 16α,17α-epoxide 1 with sodium azide affords the 16β,17α-azido alcohol 2a. The analogous reaction of the 16β,17β-epoxide 4 gives the 17α,16β-azido alcohol 5a and the desired 16α,17β-azido alcohol 6a in low yield. 6a is obtained in a smooth reaction by substitution of the 16β,17β-bromohydrine 8 with sodium azide. Sodium borohydride reduction of the 16β-azido-17-ketone 9 yields the 16β,17β-azido alcohol 10a, reduction of 16α-azido-17-ketone 13 with lithium borohydride gives the 16α,17α-azido alcohol 14a. From the azido alcohols the corresponding amino alcohols 3a, 7a, 11a and 15a are prepared with hydrazine hydrate/Raney nickel. The amino alcohols give the acetic anhydride the corresponding acetylamino alcohols. The cis-amino alcohols 11a and 15a react with acetone to the corresponding oxazolidines 12 and 16.     

Synthesis of hydrazone derivatives of benzofuran and their antibacterial and antifungal activity

A series of benzofuran hydrazones 6a–6n were synthesized from benzofuran aldehyde and substituted aromatic hydrazides 5a–5n. Structures of all compounds were confimed by IR, ¹H and ¹³C NMR, and Mass spectral data. These compounds were evaluated for their antibacterial activity against gram-negative bacteria (Escherichia coli, –ve), gram-positive bacteria (Bacillus Subtillis, +ve), and antifungal activity against Candida albicans. All compounds demonstrated considerable activity against bacteria and fungi.     

Synthesis of new water-soluble phosphonate calixazacrowns and their use as drug solubilizing agents

This study presents the selective chloromethylation of calix[4](aza)crown ethers 2a–c, using chloromethyl n-octyl ether and SnCl₄ in chloroform at room temperature in good yield for the first time. Chloromethylated products 2a–c are used as key intermediates to synthesize new water-soluble p-phosphonato calix[4](aza)crown ethers 5a–c. Liquid–liquid phase extraction and phase solubility studies with poor water soluble drug molecules such as nifedipine, niclosamide and furosemide are performed to evaluate their binding properties. Among the studied drugs, furosemide was the most effectively dissolved drug by p-phosphonato calix[4](aza)crown ethers 5a–c in water.     

Synthesis, characterization, and derivatization of some novel types of fluorinated mono- and bis-imidazolidineiminothiones with antitumor, antiviral, antibacterial, and antifungal activities

A series of thirty eight novel imidazolidineiminothiones (6a-g, 10a-h, 13a,b, 15a-d, and 16a), 5-thioxoimidazolidine-2,4-diones (7a-d, 11a-e, 14a,b, and 16b), and bis-imidazolidineiminothiones (17-20) with various fluorinated aromatic substituents at N-(1) and N-(3) were prepared in 75-85% yields. The imidazolidineiminothiones were synthesized from fluorinated N-arylcyanothioformanilides and substituted aromatic isocyanates, and by the reactions of fluorinated aromatic isocyanates with fluorinated and non-fluorinated aromatic N-arylcyanothioformanilides. Subsequent hydrolysis of selected products produced the corresponding 5-thioxoimidazolidine-2,4-diones. Preliminary screening of several compounds against Ehrlich ascites carcinoma (EAC) cells indicated that 6f and 16a were the most active (90% and 80% inhibition, respectively). Further evaluation for cytotoxicity against other tumor cell lines gave IC₅₀ values ranging from 0.67 to 3.83 μg/mL, where compounds 15a and 16a were markedly active against all cell lines. This highlights the synergistic effect of the suitably positioned fluorinated substituents on N-(1) and N-(3) of the imidazolidineiminothiones. Compounds 6a,e-g, 10a-c, 13b, 15a-d, and 17-20 were tested against microbial organisms (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typhi, and Sarcina lutea), and fungal strains (Candida albicans, Aspergillus niger, and Aspergillus flavus). Whereas compound 6a exhibited the highest antibacterial activity against Gram positive and Gram negative bacteria, 13b displayed the strongest antifungal activity against all fungal strains, reaching as high as 30 mm. Finally, 15a,b,d were subjected to in vitro testing of antiviral activity against hepatitis A virus (HAV), human herpes simplex virus 1 (HSV1), and Coxsackie B4 (COxB4) viral strain, where 15b was the most effective, reducing virus plaque count of HSV1 and COxB4 by 50% and 60%, respectively.