Synthesis and antibacterial activity of 4-benzoyl-1-(4-carboxy-phenyl)-5-phenyl-1H-pyrazole-3-carboxylic acid and derivatives

A new 1H-pyrazole-3-carboxylic acid 2, along with hydrazono-pyridazinone 3, a by-product, and its derivatives 4–7 were synthesized and the structures confirmed by infrared (IR) and ¹H and ¹³C nuclear magnetic resonance (NMR) data. These new compounds were evaluated for their antibacterial activities against Gram-positive and Gram-negative bacteria using the tube dilution method. The minimal inhibitory concentrations (MICs) experiments revealed that most compounds exerted inhibitor effects against Klebsiella pneumonia, Escherichia coli, Bacillus subtilus, and Xanthomonas compestris test microorganisms. Moreover, the results showed that the pyrazolo[3,4-d]pyridazine compounds were the best compounds of the series, exhibiting antibacterial activity against both Gram-positive and Gram-negative bacteria.     

Synthesis and antimicrobial activity of [6′-methyl-4′-methoxy-2-oxo-2H-[1]-benzopyran)-2″,4″-dihydro-[1″, 2″, 4″]-triazol-3″-one and 3″-phenyl-thiazolidin-4″-one-phenoxymethyl derivatives of dipyranoquinoline

A series of bioactive 3H,7H,8H,11H-9-[(5″-(6′-methyl-2-oxo-2H-[1]-4′-benzopyranoxy)-2″,4″-dihydro-[1″,2″,4″]-triazol-3″-one)methyl]-3,8,11-trioxo-dipyrano[2,3-f;2,3-c]quinoline (4) and 3H,7H,8H,11H-9-[(2′-(3″-phenyl-thiazolidin-4″-one)-phenoxymethyl]-3,8,11-trioxo-dipyrano[2,3-f;2,3-c]quinoline (7) analogs of 3H,7H,8H,11H-9-bromomethyl-3,8,11-trioxo-dipyrano[2,3-f;2,3-c]quinoline (1) have been synthesized and evaluated for their antibacterial activity against Gram-positive bacteria (S. aureus) and Gram-negative bacteria (S. typhi and E. coli). Pyranoquinolines with triazole and thiazolidine moieties exhibited promising antibacterial activity. The structures of all synthesised compounds were confirmed on the basis of analytical and spectral data.     

Synthesis and evaluation of in vitro antitubercular activity and antimicrobial activity of some novel 4H-chromeno[2,3-d]pyrimidine via 2-amino-4-phenyl-4H-chromene-3-carbonitriles

Novel 5-phenyl-1,5-dihydro-2H-chromeno[2,3-d]pyrimidine-2,4(3H)-dithiones, 5-phenyl-3,5-dihydro-4H-chromeno[2,3-d]pyrimidin-4-ones, 7-phenyl-7,9-dihydro-8H pyrimido[5′,4′:5,6]pyrano[3,2-h]quinolin-8-ones, and 4-amino-5-phenyl-1,5-dihydro-2H-chromeno[2,3-d]pyrimidine-2-thiones were synthesized form 2-amino-4-phenyl-4H-chromene-3-carbonitrile. The newly synthesized compounds were characterized by IR, ¹H-NMR, ¹³C-NMR, Mass spectra, and Elemental analysis. The compounds were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H ₃₇ Rv and antibacterial activity against Staphylococcus Aureus [ATCC-25923] and Streptococcus pyogenes [MTCC-443] as Gram-positive, Escherichia coli [ATCC-25922], and Pseudomonas aeruginosa [MTCC-441] as Gram-negative bacterial strains and antifungal activity against Aspergillus niger [MTCC-282]. Some of these derivatives exhibited pronounced antitubercular and antimicrobial activities.     

Synthesis of new series of pyrazolo[4,3-d]pyrimidin-7-ones and pyrido[2,3-d]pyrimidin-4-ones for their bacterial and cyclin-dependent kinases (CDKs) inhibitory activities

Two series of pyrazolo[4,3-d]pyrimidin-7-ones and pyrido[2,3-d]pyrimidin-4-ones were designed, synthesised, and evaluated for their antibacterial activities and CDKs inhibitory activities. The pyridazine derivative: 6-phenyl-5-phenylhydrazono-2,3,4,5-tetrahydropyridazine-3,4-dione (3a) revealed activity against Staphylococcus aureus as Gram-positive bacteria while compound 2-(2-Ethoxyphenyl-5-Phenylpiperazinosulfonamido)-3H-pyrido[2,3-d]pyrimidin-4-one (13c) was showing moderate antifungal activity against Candida albicans.     

Microwave-assisted synthesis of some new tetrazolo[1,5-a]quinoline-based benzimidazoles catalyzed by p-TsOH and investigation of their antimicrobial activity

Keeping the objective to build up a new structural class of potent antimicrobials, a series of some new 4-Benzimidazol-2-yl tetrazolo[1,5-a]quinoline derivatives has been synthesized by reaction of tetrazolo[1,5-a]quinoline-4-carbaldehyde and o-phenylenediamine in the presence of an organocatalyst p-TsOH under the influence of microwave irradiation. The identity of all the compounds has been established by ¹H NMR, ¹³C NMR, FTIR, and elemental analysis. The synthesized compounds were subjected to in vitro antimicrobial screening against a representative panel of pathogenic strains including three Gram-positive bacteria (Bacillus subtilis, Clostridium tetani, and Streptococcus pneumoniae) and three Gram-negative bacteria (Escherichia coli, Salmonella typhi, and Vibrio cholerae) as well as two fungal organisms (Aspergillus fumigatus and Candida albicans) by employing broth microdilution method. Of the compounds studied, compound 5e demonstrated significant activity against a Gram-positive bacteria Bacillus subtilis.     

Synthesis and antiviral activity of new 4-(phenylamino)/4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acids derivatives

The synthesis of new 4-(phenylamino)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (3a-l) derivatives and the new 4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acid (5a–c) derivatives was achieved with an efficient synthetic route. Ethyl 4-chloro-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate (1) on fusion with appropriate substituted anilines or aminopicolines gave the required new ethyl 4-(phenylamino)-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylates (2a–l) (52–82%) or new ethyl 4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylates (4a–c) (50–60%), respectively. Subsequent hydrolysis of the esters afforded the corresponding carboxylic acids (3a–l) (86–93%) and (5a–c) in high yield (80–93%). Inhibitory effects of 4-(phenylamino)/4-[(methylpyridin-2-yl)amino]-1-phenyl-1H-pyrazolo[3,4-b]pyridine-4-carboxylic acids. Derivatives on Herpes simplex virus type 1 (HSV-1), Mayaro virus (MAY) and vesicular stomatitis virus (VSV) were investigated. Compounds 2d, 3f, 3a, and 3c exhibited antiviral activity against HSV-1, MAY, and VSV virus with EC₅₀ values of 6.8, 2.2, 4.8, 0.52, 2.5, and 1.0. None of these compounds showed toxicity for Vero cells.     

A novel and eco-friendly procedure for the synthesis of some pyrazolo-thiadiazolo-pyrimidinones and its in vitro anti-bacterial activity

A novel series of 2-substituted-aminomethyl-8-phenyl-pyrazolo[3,4-d][1,3,4]thiadiazolo[3,2-a]pyrimidin-4(1H)-ones have been synthesized by treating 2-chloromethyl-8-phenyl-pyrazolo[3,4-d][1,3,4]thiadiazolo[3,2-a]pyrimidin-4(1H)-one with various nucleophiles. The chloromethyl derivative was prepared by treating 2-amino-3-mercapto pyrazolo[3,4-d]pyrimidine with one carbon donor, chloroacetic acid. The intermediate 2-amino-3-mercapto pyrazolo[3,4-d]pyrimidine was prepared by a novel, eco-friendly route starting from 2-amino-3-carbethoxy-1-phenyl-pyrazole. The target compounds exhibited broad-spectrum antibacterial activity (Kirby Bauer’s Method).     

Synthesis characterization and biological evaluation of some alkoxyphthalimide derivatives of 3-(4-substituted phenyl)-6,6-diphenyl-3,3a-dihydro-2H-imidazo[2,1-b]pyrazolo[3,4-d][1,3]thiazol-7(6H)-one

A series of 2-N-ethoxyphthalimido 3-(4-substitutedphenyl)-6,6-diphenyl-3,3a-dihydro-2H-imidazo[2,1-b]pyrazolo[3,4-d][1,3]thiazol-7(6H)-one(7a–e) and 4-(4-substituted phenyl)-2-(N-ethoxyphthalimido amino)-7,7-diphenylimidazo[2′,1′:2,3][1,3]thiazolo[4,5-d] pyrimidin-8(7H)-one (9a–e) have been designed and synthesized starting from thiohydentoin (1). The structure of all synthesized compounds has been established by IR, ¹H NMR, ¹³C NMR and mass studies. These compounds have been screened for antimicrobial activities in order to evaluate the possibility of the derivatives to be used as potential chemotherapeutic agents.     

Synthesis,Anti-Inflammatory,and Ulcerogenicity Studies of Novel Substituted and Fused Pyrazolo[3,4-d]pyrimidin-4-ones

In the present investigation, some new pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives (7–12) as well as fused pyrazolo[3′,4′:4,5]pyrimido[1,2-b]pyridazin-4(1H)-one (14–16) and 7,8,9,10-tetrahydropyrazolo[3′,4′:4,5]pyrimido[1,2-b]-cinnolin-4(1H)-one (17) ring systems were synthesized using the starting compound 5-amino-6-methyl-1-phenyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one (5). The structures of the newly synthesized compounds were elucidated by IR, ¹H NMR, ¹³C NMR, mass spectroscopy, and elemental analysis. The theoretical calculation of their lipophilicity as C log P was performed. The anti-inflammatory activity of all newly synthesized compounds was evaluated using the carrageenan-induced paw edema test in rats using indomethacin as the reference drug. Ulcer indices for the most active compounds were calculated. Seven compounds (10b, 11a–f) showed consistently good anti-inflammatory activity. In particular, 5-{[4-(4-bromophenyl)-3-(4-chlorophenyl)-1,3-thiazol-2(3H)-ylidene]amino}-6-methyl-1-phenyl-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one (11e) and its 3,4-bis(4-chlorophenyl) analog (11f) were found to be the most effective among the other derivatives, showing activity comparable to that of indomethacin with minimal ulcerogenic effects. Correlation of the biological data of the active compounds with their theoretically calculated C log P values revealed that lipophilicity influences the biological response.     

Synthesis and in?vitro antimicrobial activity of benzo[b][1,4]thiazin-3(4H)-ones via smiles rearrangement

New benzo[b][1,4]thiazin-3(4H)-one derivatives (compounds 12a–p) were synthesized via Smiles rearrangement and assayed in vitro for their antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. The antimicrobial activity of the benzo[b][1,4]thiazin-3(4H)-ones showed, on the whole, potent toward all tested Gram-positive and Gram-negative microorganism (minimal inhibitory concentration ranging from 16 to 64 μg/ml), whereas weak effectiveness was exhibited against fungi. Data obtained suggested that 12g, 12i, and 12o exerted the best antibacterial activity against Gram-positive bacteria and compound 12b demonstrated the best inhibition of Gram-negative bacteria. These observations provide some predictions to design further antimicrobial active compounds prior to their synthesis following with molecular modeling studies.     

Heterocyclen via Mannichbasen, 7. Mitt. Synthese von Pyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-9(4H)-onen

Heterocycles via Mannich Bases, VII: Synthesis of Pyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-9(4H)-ones The title compounds 4 are synthesised from 5-amino-3-methylpyrazolo[1,5-a]pyrimidin-7(4H)-one (2) and ketone Mannich bases or dehydro Mannich bases.     

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.     

Chemical Constituents of Pseudopterogorgia Species of the Indian Ocean

Abstract

A new ceramide, (2S,3R,4E)-1,3-dihydroxy-2-[(hexadecanoyl)amino]-nonadeca-4-ene (1), cholest-5-en-3β,7β,19-triol (2), identified as its, peracetyl derivative (3), and batyl alcohol (4) were isolated from Pseudopterogorgia species. 1 exhibited antibacterial activity against Gram-positive and Gram-negative bacteria.     

Pyrido[3,4-d]pyrimidin-4(3H)-one metabolism mediated by aldehyde oxidase is blocked by C2-substitution

1.?We have previously described C8-substituted pyrido[3,4-d]pyrimidin-4(3H)-one derivatives as cell permeable inhibitors of the KDM4 and KDM5 subfamilies of JmjC histone lysine demethylases.

2.?Although exemplar compound 1 exhibited moderate clearance in mouse liver microsomes, it was highly cleared in vivo due to metabolism by aldehyde oxidase (AO). Similar human and mouse AO-mediated metabolism was observed with the pyrido[3,4-d]pyrimidin-4(3H)-one scaffold and other C8-substituted derivatives.

3.?We identified the C2-position as the oxidation site by LC-MS and ¹H-NMR and showed that C2-substituted derivatives are no longer AO substrates.

4.?In addition to the experimental data, these observations are supported by molecular modelling studies in the human AO protein crystal structure.     

Biological evaluation of novel 1,4-dithiine derivatives as potential antimicrobial agents

The preparation of twelve aminoalkanol derivatives of 2,3-dihydro-5H-[1,4]dithiino[2,3-c]pyrrole-5,7(6H)-dione was described. Newly obtained compounds, as well as their propyl and butyl analogues, were evaluated in vitro against selected viruses. Selected derivatives were tested for their antibacterial and antifungal activity. Compounds 3h, 3j, 4b and 5a–d showed moderate to significant protections against CVB-2, HSV-1 and YFV viruses. The molecular structures of 4a, 5c and 5g were determined by an X-ray analysis.     

Diuretika, 3. Mitt. 1-Carbocyclisch und heterocyclisch substituierte 4-Aminopyrazolo[3,4-d]pyrimidine

Diuretics, III: 4-Aminopyrazolo[3,4-d]pyrimidines with Carbocyclic or Heterocyclic Substituents at N-1 As analogues of the diuretically active 4,6-diamino-1-(2-pyridyl)-1H-pyrazolo[3,4-d]pyrimidine, the 4-aminopyrazolo[3,4-d]pyrimidines 3a–g were prepared by condensation of the 5-amino-4-cyanopyrazoles 1a–g with formamide (2) .     

Synthesis and antibacterial evaluation of typharin analog: 6,8-dihydroxy-7-methyl-3-styryl-3,4-dihydroisocoumarin

Synthesis of the 6-hydroxy-7-methyl analog of typharin (8-dihydroxy-3-styryl-3,4-dihydroisocoumarin) isolated from the rhizomes of Typha capensis has been described. Direct condensation of 3,5-dimethoxy-4-methylhomophthalic acid (1) with cinnamoyl chloride at elevated temperature under inert conditions afforded 6,8-dihydroxy-7-methyl-3-styrylisocoumarin (2). Hydrolysis of isocoumarin to keto acid (3) followed by reduction and cyclodehydration of hydroxy acid analog (4) afforded ( ± )-6,8-dimethoxy-3-(4-methoxyphenyl)-3,4-dihydroisocoumarin (5). Demethylation of the latter using anhydrous aluminum chloride/ethane thiol furnished the title isocoumarin (6). Compounds (1–6) were screened for in vitro antibacterial activity against a representative panel of Gram-positive and Gram-negative bacteria using levofloxacin as the reference drug.     

Studies on 3,5-Diaminopyrazoles: Synthesis of New Polyfunctionally Substituted Pyrazoloazines and Pyrazoloazoles

New aminopyrazolo[1,5-a]pyrimidines, pyrazolo[3,4-d]pyrimidines and imidazo[1,2-b]pyrazoles were synthesised from ethyl 3,5-diaminopyrazole-4-carboxylate (1) .     

Novel Pirfenidone Analogs as Antifibrotic Agents: Synthesis and Antifibrotic Evaluation of 2-Pyridones and Fused Pyridones

A new series of substituted 1-(2-ethylphenyl)-2-oxo-1,2-dihydropyridine-3-carbonitriles have been synthesized. Moreover, substituted bicyclic derivatives e.g. thieno[3,4-c]pyridone, pyrido[3,4-c]pyridone, benzo[c]pyridone, and tricyclic derivatives, chromeno[3,4-c]pyridones have been prepared and evaluated for their antifibrotic activity. Among the tested compounds, compounds 4d and 5a exhibited potent antifibrotic activity without harmful side effects on liver and kidney functions. Detailed synthesis, spectroscopic and biological data are reported.     

New phenolic glycosides from the seeds of Cucurbita moschata

Two new phenolic glycosides were isolated from the seeds of Cucurbita moschata. Their structures were elucidated as (2-hydroxy)phenylcarbinyl 5-O-benzoyl-β-d-apiofuranosyl(1 → 2)-β-d-glucopyranoside (1) and 4-β-d-(glucopyranosyl hydroxymethyl)phenyl 5-O-benzoyl-β-d-apiofuranosyl(1 → 2)-β-d-glucopyranoside (2) on the basis of spectroscopic analysis and chemical evidence.