Synthesis and antimicrobial activity of some new 1,3,4-thiadiazole derivatives

Modeling the structure and reactivity landscapes of a pyrazole-ammonium ionic derivative using wavefunction-dependent characteristics and screening for potential anti-inflammatory activity

Spectroscopic investigations of 1-phenyl -2,3-dimethyl-5-oxo-1,2-dihydro-1H-pyrazol-4-ammonium 2[(2-carboxyphenyl) disulfanyl]benzoate (PACB) reported experimentally and theoretically. NH-O interaction is observed and there is a very large downshift for NH-O stretching frequency. Reactive sites are identified from the chemical and electronic properties. For PACB the maximum repulsion was around H33, H55 and H57 atom. LOL shows red regions between C-C and blue around C atoms are surrounded by a delocalized electron cloud. The red ring is a hallmark of electron density depletion from the NCI plot due to electrostatic repulsion and its existences suggests that coordination sphere for PACB is minimally strained around the central ion. Atomic contact energy values and high score of the docking results obtained propose that, PACB may have inhibitory properties and have a significant function in pharmacological chemistry. Molecular dynamics simulation was performed to validate the stability of the title compound with the Bovine thrombin-activatable fibrinolysis inhibitor protein.Communicated by Ramaswamy H. Sarma.

Synthesis and characterization of new 1,3,4-thiadiazole derivatives: study of their antibacterial activity and CT-DNA binding

1,3,4-Thiadiazole molecules (1-4) were synthesized by the reaction of phenylthiosemicarbazide and methoxy cinnamic acid molecules in the presence of phosphorus oxychloride, and characterized with UV, FT-IR, ¹³C-NMR, and ¹H-NMR methods. DFT calculations (b3lyp/6-311++G(d,p)) were performed to investigate the structures' geometry and physiochemical properties. Their antibacterial activity was screened for various bacteria strains such as Enterobacter aerogenes, Escherichia coli ATCC 13048, Salmonella kentucky, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus and Gram positive such as Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 7644, Enterococcus faecium, Enterococcus durans, Staphylococcus aureus ATCC, Serratia marcescens, Staphylococcus hominis, Staphylococcus epidermidis, alfa Streptococcus haemolyticus, Enterococcus faecium and found to have an inhibitory effect on Klebsiella pneumoniae and Staphylococcus hominis, while molecules 1, 3 and 4 had an inhibitory effect on Staphylococcus epidermidis and alpha Streptococcus haemolyticus. The experimental results were supported by the docking study using the Kinase ThiM from Klebsiella pneumoniae. All the investigated compounds showed an inhibitory effect for the Staphylococcus epidermidis protein. In addition, the mechanism of the 1-4 molecule interaction with calf thymus-DNA (CT-DNA) was investigated by UV-vis spectroscopic methods.

Benzo[4,5]imidazo[1,2-a]pyridines and benzo[4,5]imidazo[1,2-a]pyrimidines: recent advancements in synthesis of two diversely important heterocyclic motifs and their derivatives

Nitrogen heterocycles are some of the most important compounds that are found in nature or synthesized otherwise.

Quantification of a New Antifungal Drug Based on 1,3,4-Thiadiazole by HPLC-ESI/MS: Method Development, Validation and Pharmacokinetic Application

The high sensitive HPLC-ESI/MS method for quantitative determination of a new antifungal drug - 2-[(1Z)-1-(3,5-diphenyl-1,3,4-thiadiazol-2(3Н)-ylidene)methyl]-3,5-diphenyl-1,3,4-thiadiazol-3-ium chloride (TDZ) - was developed and fully validated. TDZ was separated from plasma and urine samples by acetonitrile deproteinization and extraction without time-consuming sample preparation. The reversed-phase high-performance liquid chromatography on Kromasil 100-3.5 C8 column of TDZ in isocratic elution mode using 0.03% trifluoroacetic acid : acetonitrile (65:35, v/v) at a flow rate of 0.2 mL min^-1 was performed. Determination of TDZ was carried out by a positive electrospray ionization in a selected ion monitoring mode for [M⁺]=489 m/z. The method of absolute calibration was used for quantification of TDZ in two concentrations ranges: 100-2500 pg mL^-1 and 2500-30 000 pg mL^-1. The established method showed a good linearity (R=0.999 for both ranges), the limits of determination and quantification were 50 and 100 pg mL^-1, respectively. The Intra- and Inter-day precision values were measured by t-Distribution and Fisher's Exact Test and were in accordance with the regulatory guidance. Low matrix effects and good recovery were found for TDZ. The present method was successfully applied to determine the pharmacokinetic parameters of TDZ by means of intravenous and oral administrations to rats at 5.0 mg kg^-1 and 10.0 mg kg^-1, respectively.

Synthesis and Antiviral Activity of Novel 1,4-Pentadien-3-one Derivatives Containing a 1,3,4-Thiadiazole Moiety

1,4-Pentadien-3-one derivatives derived from curcumin possess excellent inhibitory activity against plant viruses. On the basis of this finding, a series of novel 1,4-pentadien-3-one derivatives containing a 1,3,4-thiadiazole moiety were designed and synthesized, and their structures confirmed by IR, ¹H-NMR, and ¹³C-NMR spectroscopy and elemental analysis. The antiviral activities of the title compounds were evaluated against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) in vivo. The assay results showed that most of compounds had remarkable antiviral activities against TMV and CMV, among which compounds 4b, 4h, 4i, 4k, 4o, and 4q exhibited good curative, protection, and inactivation activity against TMV. Compounds 4h, 4i, 4k, 4l, 4o, and 4q exhibited excellent protection activity against TMV, with EC₅₀ values of 105.01, 254.77, 135.38, 297.40, 248.18, and 129.87 μg/mL, respectively, which were superior to that of ribavirin (457.25 µg/mL). In addition, preliminary SARs indicated that small electron-withdrawing groups on the aromatic ring were favorable for anti-TMV activity. This finding suggests that 1,4-pentadien-3-one derivatives containing a 1,3,4-thiadiazole moiety may be considered as potential lead structures for discovering new antiviral agents.

Electrochemical flow injection analysis of hydrazine in an excess of an active pharmaceutical ingredient: achieving pharmaceutical detection limits electrochemically

The quantification of genotoxic impurities (GIs) such as hydrazine (HZ) is of critical importance in the pharmaceutical industry in order to uphold drug safety. HZ is a particularly intractable GI and its detection represents a significant technical challenge. Here, we present, for the first time, the use of electrochemical analysis to achieve the required detection limits by the pharmaceutical industry for the detection of HZ in the presence of a large excess of a common active pharmaceutical ingredient (API), acetaminophen (ACM) which itself is redox active, typical of many APIs. A flow injection analysis approach with electrochemical detection (FIA-EC) is utilized, in conjunction with a coplanar boron doped diamond (BDD) microband electrode, insulated in an insulating diamond platform for durability and integrated into a two piece flow cell. In order to separate the electrochemical signature for HZ such that it is not obscured by that of the ACM (present in excess), the BDD electrode is functionalized with Pt nanoparticles (NPs) to significantly shift the half wave potential for HZ oxidation to less positive potentials. Microstereolithography was used to fabricate flow cells with defined hydrodynamics which minimize dispersion of the analyte and optimize detection sensitivity. Importantly, the Pt NPs were shown to be stable under flow, and a limit of detection of 64.5 nM or 0.274 ppm for HZ with respect to the ACM, present in excess, was achieved. This represents the first electrochemical approach which surpasses the required detection limits set by the pharmaceutical industry for HZ detection in the presence of an API and paves the wave for online analysis and application to other GI and API systems.

One-pot synthesis of benzo[4,5]imidazo[1,2-a]quinazoline derivatives via facile transition-metal-free tandem process

A one-pot transition metal-free method for synthesizing benzo[4,5]imidazo[1,2-a]quinazoline and imidazo[1,2-a]quinazoline derivatives has been developed. The approach is widely applicable to 2-fluoro-, 2-chloro-, 2-bromo- and 2-nitro-substituted aryl aldehyde and ketone substrates. The fluorescence properties of target compounds were studied.

Synthesis of 2-phenylazonaphtho[1,8-ef][1,4]diazepines and 9-(3-arylhydrazono)pyrrolo[1,2-a]perimidines as antitumor agents

Two series of naphtho[1,8-ef][1,4]diazepines and pyrrolo[1,2-a]perimidines were prepared starting from 1,8-diaminonaphthalene and hydrazonoyl chlorides. The structures of the products were determined on the basis of their spectral data and elemental analyses. The mechanism of formation of such products was also discussed. The prepared compounds were screened for their antitumor activity against three cell lines, namely, MCF-7, TK-10 and UACC-62, and some derivatives showed promising activity.