Chitosan supported ionic liquid, a multifaceted catalyst for streamlined and efficient synthesis of carboxylic, amino acid and carbohydrate esters

This work presents a sustainable approach for synthesizing esters from carboxylic acids, amino acids and carbohydrates using a robust and eco-friendly chitosan-incorporated ionic liquid under solvent-free conditions. Ionic liquids with carbon chain lengths ranging from 3 to 8 were integrated into the chitosan molecule, resulting in a heterogeneous catalyst optimized for esterification reactions. Among these, the 6-carbon chain ionic liquid demonstrated superior catalytic activity and substrate tolerance. The catalyst's effectiveness was confirmed using advanced analytical techniques. The acidity of the ionic liquid was assessed by observing the interaction between the synthesized IL6 (1,4-bis(5-carboxypentyl)pyrazine-1,4-diium ([BCPPD][Br])) and p-nitroaniline via UV-Vis studies. Chitosan-IL6, an ionic liquid supported on chitosan, functions as a heterogeneous catalytic system that can be easily removed from reaction mixtures through simple filtration. It also exhibits excellent reusability, maintaining high catalytic activity and structural integrity over 10 catalytic cycles. Moreover, the methodology was successfully scaled up for the gram-scale synthesis of key compounds such as diisopropyl azodicarboxylate, methyl nicotinate, methyl cysteinate, and glucose pentaacetate, highlighting its practical viability.

I2-catalyzed one-pot oxidative condensation of thiourea, methyl ketones, and aryl thiols into 5-sulfenylated 2-amino-1,3-thiazoles by DMSO

A one-pot, efficient oxidative-condensation process for constructing both 4-alkyl and 4-aryl-5-(arylthio) thiazol-2-amines using DMSO/I2 is introduced. In this procedure, methyl ketones, thiourea, DMSO, and thiols are reacted together in the presence of molecular I2 at 80 °C simply to produce 4-alkyl or aryl-5-(arylthio)thiazol-2-amines due to formation of a C-S bond between thiourea and methyl carbon linked to carbonyl group and the another C-S bond formation between thiol and thiazol ring. Under reaction conditions, both aryl and alkyl methyl ketones including acetophenone and substituted acetophenones also, 2-alkanones such as acetone, 2-butanone, 2-pentanone, and 2-heptanone yield those products successfully.

Design of a new method for one-pot synthesis of 2-amino thiazoles using trichloroisocyanuric acid in the presence of a novel multi-functional and magnetically catalytic nanosystem: Ca/4-MePy-IL@ZY-Fe3O4

In this study, an effective approach was developed to synthesize a novel, multifunctional ionic liquid nanocatalyst based on zeolite-Y with 4-methylpyridinium chloride (4-MePy-Cl) and calcium ions (Ca/4-MePy-IL@ZY). Then, Fe₃O₄ nanoparticles were produced inside the zeolite pores with the use of ultrasonic waves. XRD, FESEM, FT-IR, EDX-Map, TGA-DTA, VSM, BET, and atomic absorption techniques were used to identify the structure of the magnetic nanocomposite. Then, its catalytic activity in the one-pot synthesis of 2-aminothiazoles using trichloroisocyanuric acid (TCCA) as a green supplier of halogen ions for intermediates was studied. To provide ideal conditions for the preparation of pure products, first, the one-pot reaction of acetophenone and thiourea in various solvents, different temperatures, and the presence of different amounts of nanocatalysts and the molar amount of TCCA was used. Next, the reaction was investigated in the one-pot preparation of 2-aminothiazole derivatives under optimal conditions. This method replaces iodine (I₂), a toxic reagent, for the first time with TCCA, a safe and sustainable source of halogen. The use of non-toxic solvent and a cheap, safe, recyclable nanocatalyst, quick reaction times, high efficiency, and ease of nanocatalyst separation with the aid of a magnet are additional benefits of this method. This has led to this procedure being classified as "green chemistry".

Synthesis of novel calcium channel blockers with ACE2 inhibition and dual antihypertensive/anti-inflammatory effects: A possible therapeutic tool for COVID-19

Hypertension has been recognized as one of the most frequent comorbidities and risk factors for the seriousness and adverse consequences in COVID-19 patients. 3,4-dihydropyrimidin-2(1H) ones have attracted researchers to be synthesized via Beginilli reaction and evaluate their antihypertensive activities as bioisosteres of nifedipine a well-known calcium channel blocker. In this study, we report synthesis of some bioisosteres of pyrimidines as novel CCBs with potential ACE2 inhibitory effect as antihypertensive agents with protective effect against COVID-19 infection by suppression of ACE2 binding to SARS-CoV-2 Spike RBD. All compounds were evaluated for their antihypertensive and calcium channel blocking activities using nifedipine as a reference standard. Furthermore, they were screened for their ACE2 inhibition potential in addition to their anti‐inflammatory effects on LPS-stimulated THP‐1 cells. Most of the tested compounds exhibited significant antihypertensive activity, where compounds 7a, 8a and 9a exhibited the highest activity compared to nifedipine. Moreover, compounds 4a,b, 5a,b, 7a,b, 8a,c and 9a showed promising ACE2:SARS-CoV-2 Spike RBD inhibitory effect. Finally, compounds 5a, 7b and 9a exerted a promising anti-inflammatory effect by inhibition of CRP and IL-6 production. Ultimately, compound 9a may be a promising antihypertensive candidate with anti-inflammatory and potential efficacy against COVID-19 via ACE2 receptor inhibition.

Synthesis and photoelectric properties of IrIII complexes using fluorobenzylimidazole[2,1-b]thiazole derivatives as primary ligands

Twelve novel phosphorescent IrIII complexes based on fluorobenzimidazole[2,1-b]thiazole derivatives as primary ligands with luminescent nearly full colors.