Convenient Michael addition/β-elimination approach to the synthesis of 4-benzyl- and 4-aryl-selenyl coumarins using diselenides as selenium sources

4-(Phenylselanyl)-2H-chromen-2-one-Loaded Nanocapsule Suspension-A Promising Breakthrough in Pain Management: Comprehensive Molecular Docking, Formulation Design, and Toxicological and Pharmacological Assessments in Mice

Therapies for the treatment of pain and inflammation continue to pose a global challenge, emphasizing the significant impact of pain on patients' quality of life. Therefore, this study aimed to investigate the effects of 4-(Phenylselanyl)-2H-chromen-2-one (4-PSCO) on pain-associated proteins through computational molecular docking tests. A new pharmaceutical formulation based on polymeric nanocapsules was developed and characterized. The potential toxicity of 4-PSCO was assessed using Caenorhabditis elegans and Swiss mice, and its pharmacological actions through acute nociception and inflammation tests were also assessed. Our results demonstrated that 4-PSCO, in its free form, exhibited high affinity for the selected receptors, including p38 MAP kinase, peptidyl arginine deiminase type 4, phosphoinositide 3-kinase, Janus kinase 2, toll-like receptor 4, and nuclear factor-kappa β. Both free and nanoencapsulated 4-PSCO showed no toxicity in nematodes and mice. Parameters related to oxidative stress and plasma markers showed no significant change. Both treatments demonstrated antinociceptive and anti-edematogenic effects in the glutamate and hot plate tests. The nanoencapsulated form exhibited a more prolonged effect, reducing mechanical hypersensitivity in an inflammatory pain model. These findings underscore the promising potential of 4-PSCO as an alternative for the development of more effective and safer drugs for the treatment of pain and inflammation.

Pd-Catalyzed Alkyne and Aryne Annulations: Synthesis and Photophysical Properties of π-Extended Coumarins

A Pd-catalyzed alkyne and aryne annulation strategy via C-H activation has been implemented for the synthesis of π-extended coumarins. This synthetic strategy provides a wide range of π-extended coumarins in moderate to good yields with good functional group compatibility. Photophysical properties of the synthesized π-extended coumarins have been evaluated, and some of them show interesting fluorescent properties. Three of the synthesized coumarins have been unambiguously established by a single-crystal XRD study.

Sinapic Acid Esters: Octinoxate Substitutes Combining Suitable UV Protection and Antioxidant Activity

In 2021, Hawaii will permanently ban the use and sale of octinoxate-based sunscreens as studies have shown serious impacts of such UV filters on the coral reef. This ban, which could be generalized to other countries, highlights the extreme need to offer alternative UV filters that are not only effective in terms of sun protection, but also healthy with regards to human health and the environment. In this context, a wide library of p-hydroxycinnamic esters deriving from naturally occurring sinapic acid has been synthesized using a Knoevenagel–Doebner condensation. The UV filtering activities as well as the antioxidant properties of these sinapic acid esters were then investigated. The results showed promising UVB protection and antioxidant efficacy. A Structure–Activity Relationship (SAR) study on the sinapic acid esters highlighted the need of a free phenol to, as expected, observe antioxidant activity, but also to obtain a higher intensity of protection. Moreover, the nature of the ester moiety also proved to be a key structural feature for the UV absorbance, as higher steric hindrance on the ester moiety leads to more active compounds. The judicious structural design of sinapic esters thus provides promising compounds combining UV protection and antioxidant activity.

A pyrazole-containing selenium compound modulates neuroendocrine, oxidative stress, and behavioral responses to acute restraint stress in mice

The contribution of oxidative stress has been described in numerous studies as one of the main pathways involved in the pathophysiology of anxiety and its comorbidities, such as chronic pain. Therefore, in this study, we investigated the anxiolytic-like, antiallodynic, and anti-hyperalgesic effects of 3,5-dimethyl-1-phenyl-4-(phenylselanyl)-1H-pyrazole (SePy) in response to acute restraint stress (ARS) in mice through the modulation of oxidative stress and neuroendocrine responses. Mice were restrained for 2 h followed by SePy (1 or 10 mg/kg, intragastrically) treatment. Behavioral, and biochemical tests were performed after further 30 min. The treatment with SePy reversed (i) the decreased time spent and the number of entries in the open arms of the elevated plus-maze apparatus, (ii) the decreased time spent in the central zone of the open field test and the increased number of grooming, (iii) the increased number of marbles buried, (iv) the increased response frequency of Von Frey Hair stimulation, and (v) the decreased latency time to nociceptive response in the hot plate test stress induced by ARS. Biochemically, SePy reversed ARS-induced increased levels of plasma corticosterone, and reversed the ARS-induced alterations in the levels of reactive species, lipid peroxidation, and superoxide dismutase and catalase activities in the prefrontal cortices and hippocampi of mice. Moreover, a molecular docking approach suggested that SePy may interact with the active site of the glucocorticoid receptor. Altogether, these results indicate that SePy attenuated anxiolytic-like behavior, hyperalgesia, and mechanical allodynia while modulating oxidative stress and neuroendocrine responses in stressed mice.

Efficient synthesis of 4-sulfanylcoumarins from 3-bromo-coumarins via a highly selective DABCO-mediated one-pot thia-Michael addition/elimination process

A facile and efficient protocol for the highly selective direct sulfanylation of 3-bromocoumarins under DABCO promotion, was developed. The transformation took place with aromatic and aliphatic thiols as well as with α,ω-dithiols, affording the expected products in very good to excellent yields. Simple and convenient ways to access 4-((ω-mercaptoalkyl) thio)coumarins and the dimeric 4,4′-(alkane-1,4-diylbis(sulfanediyl))bis(coumarins) were also devised with the use of α,ω-alkanedithiols in different ratios with regards to the starting 3-bromocoumarin. The transformation seems to proceed through the DABCO-mediated thia-Michael stereoselective addition of the thiolate anion to the α,β-unsaturated carbonyl system of the coumarin, followed by a DABCO-assisted stereoselective dehydrobromination of the resulting α-bromo carbonyl intermediate.

A facile, simple and metal-free protocol for the 4-sulfanylation of 3-bromocoumarins was developed. It involves a thia-Michael addition and a dehydrobromination under DABCO assistance.

Metal and Oxidant-Free Brønsted Acid-Mediated Cascade Reaction to Substituted Benzofurans

Substituted hydroxy-benzofurans are easily accessible by treatment of resorcinols and 1,2-diaza-1,3-dienes (DDs) under acidic conditions. The reaction happens through an uncommon Michael reaction between aromatic derivatives as aromatic C(sp²)-H nucleophiles and DDs as acceptors. Also, the behavior of different phenols and 2-naphthol was investigated.

Microwave assisted synthesis of coumarin-purine derivatives: An approach to in vitro anti-oxidant, DNA cleavage, crystal structure, DFT studies and Hirshfeld surface analysis

An easy and efficient microwave-assisted protocol has been developed for the synthesis of coumarin-purine hybrids (3a-3j). The newly constructed 1,3-dimethyl-7-((substituted)-2-oxo-2H-chromen-4-yl)methyl)-1H-purine-2,6(3H,7H)-dione derivatives were evaluated for their in vitro antioxidant activity by DPPH free radical-scavenging ability assay and DNA cleavage by using calf thymus. The compound 3i, shows the most excellent DPPH scavenging activity with a –OH substitution at C7 of coumarin ring. In addition, the structure of compound 3f, has been elucidated using single crystal X-ray diffraction technique. Theoretical calculations (DFT) were carried out using Gaussian09 program package and B3LYP correlation function. Full geometry optimization were carried out using 6-311G++(d, p) basis set and the frontier orbital energy were presented. Hirshfeld surface analysis was used for the intermolecular interactions in the crystal structure. The experimental result of the compound 3f has been compared with the theoretical results and it was found that the experimental data are in a good agreement with the calculated values.

Synthesis of 2,3-bis-organochalcogenyl-benzo[b]chalcogenophenes promoted by Oxone®

We report here an alternative and tunable metal-free synthesis of benzo[b]chalcogenophenes via the electrophilic cyclization of 2-functionalized chalcogenoalkynes promoted by Oxone®.

3-Selenocyanate-indoles as new agents for the treatment of superficial and mucocutaneous infections

The development of resistance to the current antifungal agents is an alarming problem.