Evaluation of the Binding Relationship of the RdRp Enzyme to Novel Thiazole/Acid Hydrazone Hybrids Obtainable through Green Synthetic Procedure

The viral RNA-dependent RNA polymerase (RdRp) complex is used by SARS-CoV-2 for genome replication and transcription, making RdRp an interesting target for developing the antiviral treatment. Hence the current work is concerned with the green synthesis, characterization and docking study with the RdRp enzyme of the series of novel and diverse hydrazones and pyrazoles. 4-Methyl-2-(2-(1-phenylethylidene)hydrazineyl)thiazole-5-carbohydrazide was prepared and then condensed with different carbonyl compounds (aldehydes and ketones either carbocyclic aromatic or heterocyclic) afforded the corresponding hydrazide-hydrazones. The combination of the acid hydrazide with bifunctional reagents such as acetylacetone, β-ketoesters (ethyl acetoacetate and ethyl benzoylacetate) resulted in the formation of pyrazole derivatives. The synthesized compounds were all obtained through grinding method using drops of AcOH. Various analytical and spectral analyses were used to determine the structures of the prepared compounds. Molecular Operating Environment (MOE^®) version 2014.09 was used to estimate interactions between the prepared thiazole/hydrazone hybrids and RdRp obtained from the protein data bank (PDB: 7bv2) using enzyme-ligand docking for all synthesized derivatives and Remdesivir as a reference. Docking results with the RdRp enzyme revealed that the majority of the investigated drugs bind well to the enzyme via various types of interactions in comparison with the reference drug.

Heterocyclisation of 2,5-diacetyl-3,4-disubstituted-thieno[2,3-b]Thiophene Bis-Thiosemicarbazones Leading to Bis-Thiazoles and Bis-1,3,4-thiadiazoles as Anti-breast Cancer Agents

In this paper, the synthesis of bis-thiazoles and bis-1,3,4-thiadiazoles linked to a thienothiophene nucleus is described. The synthesis was achieved through interaction between 2,5-diacetylthieno[2,3-b]thiophene bis-thiosemicarbazones with a variety of hydrazonyl halides in a basic medium. All the synthesised compounds were characterised by IR, 1H NMR, 13C NMR and mass spectroscopic analyses. The newly synthesised compounds represent a variety of novel polyheteroatomic moieties containing nitrogen and sulfur. Most of the synthesised compounds were evaluated for their antitumour activity against the breast cancer MCF-7 cell line. The results revealed that four compounds are equipotent to tamoxifen (IC50 = 8.04 μg mL−1) with IC50 = 8.23, 8.26, 8.68 and 9.12 μg mL−1 respectively.

Design and Synthesis of Imidazopyrazolopyridines as Novel Selective COX-2 Inhibitors

The usefulness of non-steroidal anti-inflammatory drugs (NSAIDs) is hampered by their gastrointestinal side effects. Non-selective cyclooxygenases inhibitors interfere with both COX-1 and COX-2 isozymes. Since COX-1 mediates cytoprotection of gastric mucosa, its inhibition leads to the undesirable side effects. On the other hand, COX-2 is undetectable in normal tissues and selectively induced by inflammatory stimuli. Therefore, it is strongly believed that the therapeutic benefits derive from inhibition of COX-2 only. The presence of a strong connection between reported COX-2 inhibitors and cardiac toxicity encourages medicinal chemists to explore new scaffolds. In the present study, we introduced imidazopyrazolopyridines as new potent and selective COX-2 inhibitors that lack the standard pharmacophoric binding features to hERG. Starting from our lead compound 5a, structure-based drug-design was conducted and more potent analogues were obtained with high COX-2 selectivity and almost full edema protection, in carrageenan-induced edema assay, in case of compound 5e. Increased bulkiness around imidazopyrazolopyridines by adding a substituted phenyl ring(s) afforded less active compounds.

Novel 4-heteroaryl-antipyrines as DPP-IV inhibitors

Type 2 diabetes mellitus is a vast growing progressive disease that almost affects one person among every twelve globally. Regardless the availability of wide variety of oral hypoglycemics, only one-third of patients achieves proper glycemic control. With the advantage of the low risk of hypoglycemia, DPP-IV attracted the attention of medicinal chemists as a new target for oral hypoglycemics. In this report, a lead compound 1, with antipyrine scaffold, was obtained, and its binding mode was calculated. Several derivatives with bridged nitrogenous heterocycles have been synthesized via multicomponent reaction under controlled microwave heating conditions. The antidiabetic activity versus DPP-IV protein was evaluated and compared with sitagliptin. Compounds with smaller- or medium-sized nitrogenous bridges were comparable with sitagliptin in terms of DPP-IV inhibitory activity, potentially via targeting Glu203 and Glu204. The oral hypoglycemic activities of compounds with submicromolar IC50 values were further evaluated using diabetic mouse model.

Novel anti-HIV-1 NNRTIs based on a pyrazolo[4,3-d]isoxazole backbone scaffold: design, synthesis and insights into the molecular basis of action

Design and synthesis of novel anti-HIV-1 NNRTIs based on a pyrazolo[4,3-d]isoxazole backbone scaffold.

A Convenient Synthesis of Some New Thiazole and Pyrimidine Derivatives Incorporating a Naphthalene Moiety

The reaction of 2-[1-(naphthalen-2-yl)ethylidene]hydrazinecarbothioamide with hydrazonoyl halides afforded new thiazole derivatives, whilst reaction with compounds containing an activated double bond such as ethoxymethylene-malononitrile and benzylidenemalononitrile yielded the respective pyrimidine derivatives. A 4-thiazolidin-4-one was obtained by reaction of the hydrazinecarbothioamide with ethyl bromoacetate. Subsequent condensation of the thia-zolidinone with aromatic aldehydes afforded the corresponding arylidene derivatives. Treatment of the hydrazinecarbothioamide with dimethyl acetylenedicarboxylate resulted in the formation of a (methoxycarbonylmethylidene) thiazolinone. Reaction of the hydrazinecarbothioamide with 2-chloro-1,3-dicarbonyl compounds gave the respective thiazole derivatives. The structures of the newly synthesised compounds were confirmed by their elemental analysis and spectral data.