Synthesis and biological evaluation of novel pyrimidines derived from 6-aryl-5-cyano-2-thiouracil

Discovery of pyrimidine-tethered benzothiazole derivatives as novel anti-tubercular agents towards multi- and extensively drug resistant Mycobacterium tuberculosis

In this study, new benzothiazole-pyrimidine hybrids (5a-c, 6, 7a-f, and 8-15) were designed and synthesised. Two different functionalities on the pyrimidine moiety of lead compound 4 were subjected to a variety of chemical changes with the goal of creating various functionalities and cyclisation to further elucidate the target structures. The potency of the new molecules was tested against different tuberculosis (TB) strains. The results indicated that compounds 5c, 5b, 12, and 15 (MIC = 0.24-0.98 µg/mL) are highly active against the first-line drug-sensitive strain of Mycobacterium tuberculosis (ATCC 25177). Thereafter, the anti-tubercular activity was evaluated against the two drug-resistant TB strains; ATCC 35822 and RCMB 2674, where, many compounds exhibited good activity with MIC = 0.98-62.5 3 µg/mL and 3.9-62.5 µg/mL, respectively. Compounds 5c and 15 having the highest anti-tubercular efficiency towards sensitive strain, displayed the best activity for the resistant strains by showing the MIC = 0.98 and 1.95 µg/mL for MDR TB, and showing the MIC = 3.9 and 7.81 µg/mL for XDR TB, consecutively. Finally, molecular docking studies were performed for the two most active compounds 5c and 15 to explore their enzymatic inhibitory activities.

Design, Synthesis, Antiviral Evaluation, and Molecular Dynamics Simulation Studies of New Spirocyclic Thiopyrimidinones as anti HCoV-229E

The current pandemic threat presented by viral pathogens like SARS-CoV-2 (COVID-19) suggests that virus emergence and dissemination are not geographically confined. As a result, the quest for antiviral agents has become critical to control this pandemic. In the current study, we provide a novel family of spirocyclic thiopyrimidinone derivatives whose cytotoxicity and antiviral efficacy were investigated against human coronavirus 229E (HCoV-229E) as a model for the Coronaviridae family. We utilized MTT and cytopathic effect (CPE) inhibitory tests on green monkey kidney (vero-E6) cell line. The new molecules showed varied degrees of antiviral activity against the vero-E6 cell line with minimal cytotoxicity. With a high level of a selective index (SI = 14.8), compound 9 showed outstanding inhibitory ability and could effectively suppress the human coronavirus 229E. Molecular dynamics simulation (MD) studies were performed to measure the interaction and stability of the protein-ligand complex in motion. The MD results for the most active compound 9 explored remarkable interactions with the binding pockets of the main protease (Mpor) of SARS-CoV-2 enzyme confirming the results gained from in vitro experiments. ADMET properties were also predicted for all the tested compounds. All these results demonstrated that the novel spirocyclic thiopyrimidinone derivatives would have the potential to be safe, low-cost chemical compounds that might be used as a novel therapeutic option for Coronaviridae viruses like COVID-19.

Novel cyanothiouracil and cyanothiocytosine derivatives as concentration-dependent selective inhibitors of U87MG glioblastomas: Adenosine receptor binding and potent PDE4 inhibition

Thiouracil and thiocytosine are important heterocyclic pharmacophores having pharmacological diversity. Antitumor and antiviral activity is commonly associated with thiouracil and thiocytosine derivatives, which are well known fragments for adenosine receptor affinity with many associated pharmacological properties. In this respect, 33 novel compounds have been synthesized in two groups: 24 thiouracil derivatives (4a-x) and 9 thiocytosine derivatives (5a-i). Antitumor activity of all the compounds was determined in the U87 MG glioblastoma cell line. Compound 5e showed an anti-proliferative IC₅₀ of 1.56 μM, which is slightly higher activity than cisplatin (1.67 μM). The 11 most active compounds showed no signficant binding to adenosine A₁, A_2A or A_2B receptors at 1 μM. Brain tumors express high amounts of phosphodiesterases. Compounds were tested for PDE4 inhibition, and 5e and 5f showed the best potency (5e: 3.42 μM; 5f: 0.97 μM). Remakably, those compounds were also the most active against U87MG. However, the compounds lacked a cytotoxic effect on the HEK293 healthy cell line, which encourages further investigation.