One Pot Sequential Synthesis of N -[2-(Phenylsulfinyl)phenyl]acetamides: A Ring Opening Rearrangement Functionalization (RORF)

Novel multitarget directed ligands inspired by riluzole: A serendipitous synthesis of substituted benzo[b][1,4]thiazepines potentially useful as neuroprotective agents

Riluzole, the first clinically approved treatment for amyotrophic lateral sclerosis (ALS), represents a successful example of a drug endowed with a multimodal mechanism of action. In recent years, different series of riluzole-based compounds have been reported, including several agents acting as Multi-Target-Directed Ligands (MTLDs) endowed with neuroprotective effects. Aiming at identical twin structures inspired by riluzole (2a-c), a synthetic procedure was planned, but the reactivity of the system took a different path, leading to the serendipitous isolation of benzo[b][1,4]thiazepines 3a-c and expanded intermediates N-cyano-benzo[b][1,4]thiazepines 4a-c, which were fully characterized. The newly obtained structures 3a-c, bearing riluzole key elements, were initially tested in an in vitro ischemia/reperfusion injury protocol, simulating the cerebral stroke. Results identified compound 3b as the most effective in reverting the injury caused by an ischemia-like condition, and its activity was comparable, or even higher than that of riluzole, exhibiting a concentration-dependent neuroprotective effect. Moreover, derivative 3b completely reverted the release of Lactate Dehydrogenase (LDH), lowering the values to those of the control slices. Based on its very promising pharmacological properties, compound 3b was then selected to assess its effects on voltage-dependent Na+ and K+ currents. The results indicated that derivative 3b induced a multifaceted inhibitory effect on voltage-gated currents in SH-SY5Y differentiated neurons, suggesting its possible applications in epilepsy and stroke management, other than ALS. Accordingly, brain penetration was also measured for 3b, as it represents an elegant example of a MTDL and opens the way to further ex-vivo and/or in-vivo characterization.

Mechanistic Study on Selenium- and Sulfur-Mediated Isomerization of Hydroxamic Acids

An in-depth computational study reveals the intriguing mechanism of the recently reported isomerization of hydroxamic acids into para-aminophenols catalyzed by phenylselenyl bromide under mild conditions. The computations not only align with the reported experimental data, effectively explaining observed phenomena such as para-selectivity but also shed light on crucial aspects of the reaction mechanism that establish limitations on the scope of the studied rearrangement. Additionally, a joint theoretical/experimental study was performed to examine the potency of the phenylsulfenyl bromide to mediate the reaction under the same conditions.

Tandem Copper-Catalyzed Regioselective N-Arylation-Aza-Michael Addition: Synthesis of Tetracyclic 5H-Benzothiazolo[3,2-a]quinazoline Derivatives

A copper-catalyzed tandem process integrating regioselective N-arylation, followed by aza-Michael addition, is disclosed using 2-aminobenzothiazoles and ortho-halo cinnamic acid congeners. This process generated diverse tetracyclic 5H-benzothiazolo[3,2-a]quinazoline derivatives in moderate to good yields. The present tandem reaction appears to proceed through concomitant ring opening of 2-aminobenzothiazole and S-arylation to give the ortho-cyanamide-substituted diaryl thioether intermediate. The thus generated intermediate likely undergoes an unprecedented Truce-Smiles-type rearrangement involving S- to N-aryl migration, followed by reformation of the thiazole ring and intramolecular aza-Michael addition to furnish the title products.

Copper-Catalyzed Three-Component Redox-Neutral Ring Opening of Benzothiazoles to 1-Amino-N-(2-(phenylthio)phenyl)methanimine

Copper-catalyzed three-component redox-neutral ring opening of benzothiazoles with aryl iodides and O-benzoyl hydroxylamines for the synthesis of 1-amino-N-(2-(phenylthio)phenyl)methanimine has been developed. This one-pot reaction undergoes C-S and N-O bond cleavage and new C-S and C-N bond construction. Several control experiments excluded a free radical procedure and also demonstrated the secondary amine as a possible intermediate, which was vital to the catalytic reaction. Meanwhile, the deuteration experiment got rid of the C-H activation dehydroisomerization of the benzothiazole mechanism.