A new and efficient N-alkylation procedure for semicarbazides/semicarbazones derivatives

Biological Evaluation of Arylsemicarbazone Derivatives as Potential Anticancer Agents

Fourteen arylsemicarbazone derivatives were synthesized and evaluated in order to find agents with potential anticancer activity. Cytotoxic screening was performed against K562, HL-60, MOLT-4, HEp-2, NCI-H292, HT-29 and MCF-7 tumor cell lines. Compounds 3c and 4a were active against the tested cancer cell lines, being more cytotoxic for the HL-60 cell line with IC₅₀ values of 13.08 μM and 11.38 μM, respectively. Regarding the protein kinase inhibition assay, 3c inhibited seven different kinases and 4a strongly inhibited the CK1δ/ε kinase. The studied kinases are involved in several cellular functions such as proliferation, migration, cell death and cell cycle progression. Additional analysis by flow cytometry revealed that 3c and 4a caused depolarization of the mitochondrial membrane, suggesting apoptosis mediated by the intrinsic pathway. Compound 3c induced arrest in G1 phase of the cell cycle on HL-60 cells, and in the annexin V assay approximately 50% of cells were in apoptosis at the highest concentration tested (26 μM). Compound 4a inhibited cell cycle by accumulation of abnormal postmitotic cells at G1 phase and induced DNA fragmentation at the highest concentration (22 μM).

Design, facile synthesis and anthelmintic activity of new O-substituted 6-methoxybenzothiazole-2-carbamates. Part II

In the framework of pursuing the design and synthesis of a new series of substituted 6-methoxybenzothiazole-2-carbamates as potential anthelmintics, and as a continuation of the expended efforts in part I, we have set out to develop novel compounds with enhanced anthelmintic activity by blocking the 6-position of benzothiazole with side chains of different polarities. Guided by the findings in part I, and reporting the paramphistomicidal activity of oxadiazoline derivatives V and VI, we aimed to synthesize target benzothiazoles designed to comprise some planar heterocyclic ring systems, namely, 1,3,4-oxadiazoles and 1,2,4-triazoles, bearing a variety of hydrophobic and hydrophilic components. The synthesis of the desired compounds was primarily achieved by cyclization of 6-acetohydrazide, 1. The in vitro paramphistomicidal activity of all synthesized carbamates was evaluated. Four synthesized carbamates exhibited notable activity. Compound 24, methyl 6-[(5-(4-bromophenacylsulfanyl)-[1,3,4]-oxadiazol-2-yl)methoxy]benzothiazole-2-carbamate, displayed an equipotent effect to the reference drug oxyclozanide at a concentration of 80 μg mL^-1; compounds 9, 10 and 23 showed high orders of anthelmintic effect. A structural computational study on the polar nature and hydrophilic-lipophilic properties of the synthesized carbamates was undertaken to discuss their structure-activity relationship (SAR). Besides, pharmacophore mapping was performed using eight active compounds as a training set. The generated pharmacophore model revealed five common features and was validated using fenbendazole, triclabendazole and triclabendazole sulfoxide.

A green and efficient method for the synthesis of pyrroles using a deep eutectic solvent ([CholineCl][ZnCl2]3) under solvent-free sonication

A green and efficient method for Paal–Knorr pyrrole synthesis has been developed under mild conditions.

Design, synthesis and biological evaluation of novel unsymmetrical azines as quorum sensing inhibitors

In this report, novel unsymmetrical azines have been designed and synthesised by using one pot approach. Further, they were evaluated as quorum sensing inhibitors.

Reaction parameters for the synthesis of N,N-dimethyl fatty hydrazides from oil

Hydrazide derivatives have been synthesized from methyl esters, hydrazones and vegetable oils. They are important due to their diverse applications in pharmaceutical products, detergents as well as in oil and gas industries. The chemical synthesis of fatty hydrazides is well-established; however, only a few publications described the synthesis of fatty hydrazide derivatives, particularly, when produced from refined, bleached and deodorized palm olein. Here, the synthesis and characterization of N,N-dimethyl fatty hydrazides are reported. The N,N-dimethyl fatty hydrazides was successfully synthesized from fatty hydrazides and dimethyl sulfate in the presence of potassium hydroxide with the molar ratio of 1:1:1, 6 hours reaction time and 80℃ reaction temperature in ethanol. The product yield and purity were 22% and 89%, respectively. The fatty hydrazides used were synthesized from refined, bleached and deodorized palm olein with hydrazine monohydrate at pH 12 by enzymatic route. Fourier transform infrared, gas chromatography and nuclear magnetic resonance (NMR) spectroscopy techniques were used to determine the chemical composition of N,N-dimethyl fatty hydrazides. Proton NMR confirmed the product obtained were N,N-dimethyl fatty hydrazides.

Synthesis, NMR structural characterization and molecular modeling of substituted thiosemicarbazones and semicarbazones using DFT calculations to prove the syn/anti isomer formation

Thiosemicarbazones possessing electron-donating and electron-withdrawing groups were prepared, and their spectral characteristics determined. In all cases, the spectra showed that one isomer was formed, allowing further functionalization to molecules of biological interest. We provide NMR data for some of the thiosemicarbazones and semicarbazones. We also provide evidence that for 2-pyridyl thiosemicarbazone, the syn isomer slowly converts into the anti isomer in dimethyl sulfoxide solvent with first-order kinetics. Molecular modeling and density functional theory calculations confirmed these observations.