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This review discusses recent progress in the most significant synthetic approaches involving transformations under the Mitsunobu reaction. The Mitsunobu reaction entails the \"redox\" condensation of an acidic pronucleophile ‘Nu-H’ and an electrophilic primary or secondary alcohol, facilitated by stoichiometric amounts of phosphines and azodicarboxylate reagents. Widely utilized for dehydrative oxidation–reduction condensation, this reaction shows synthetic utility through its tolerance of a broad range of acidic pronucleophiles, including carboxylic acids, pro-imides, hydroxamates, phenols, thiols, fluorinated alcohols, oximes, thioamides, pyridinium and imidazolium salts, pyrimidine bases, α-ketoesters, and trimethylmethane tricarboxylate, thereby yielding a variety of functional and potentially biologically active compounds. The purpose of this review is to focus on recent advances and applications of Mitsunobu reaction chemistry, particularly from 2010 to 2024. In addition to discussing newer reagents that facilitate purification, we will describe contemporary applications of this chemistry, especially concerning the synthesis of potential biological compounds and their precursors. This focus review of the Mitsunobu reaction summarizes its origins, the current understanding of its mechanism, and recent improvements and applications. We aim for this work to serve as a useful resource for scientists working in this research domain.

Thiopyrimidines represent one of the most active classes of compounds, possessing a wide spectrum of biological activities. Herein, we report the synthesis of 2-(heptylthio)pyrimidine-4,6-diamine (HPDA) via S-alkylation. The structure of HPDA was elucidated using 1H and 13C nuclear magnetic resonance (NMR), heteronuclear multiple bond correlation (HMBC), high resolution mass (HRMS), and infrared (IR) spectroscopies.

Heterocyclic systems such as 1,2,4-triazoles and piperazines play an important role in modern medicinal chemistry due to their structural diversity and broad spectrum of biological activities. In this Short Note, we report the synthesis and spectroscopic characterization of a new hybrid molecule combining both pharmacophoric fragments: 1-[4-(4-chlorophenyl)piperazin-1-yl]-2-[(4-phenyl-4H-1,2,4-triazol-3-yl)sulfanyl]ethan-1-one (compound 3). The compound was obtained in 70% yield via S-alkylation of 4-phenyl-1,2,4-triazole-3-thione with a chloroacetyl derivative of 4-chlorophenylpiperazine under alkaline conditions. The structure of 3 was confirmed by 1H and 13C NMR spectroscopy, DEPT-135, 2D NMR (COSY, NOESY, HSQC, HMBC), FT-IR, and elemental analysis. These results support the utility of combining triazole and piperazine fragments in the design of new heterocyclic frameworks with potential biological relevance.

Bromination of N -acyl-2,2,4-trimethyl-1,2-dihydroquinolines with N -bromosuccinimide (NBS) in CCl 4 in the presence of Bz 2 O 2 proceeded at the 4-positioned methyl group. In a DMF solution, the direction of the reaction was determined by the nature of substituent at the nitrogen atom: the reaction with one equivalent of NBS can proceed either as described above, or at position 3 with the allylic rearrangement-type migration of the multiple bond. The use of two equimoles of NBS in DMF led to 3-bromo-4-bromometh-ylene-2,2-dimethyl-3,4-dihydroquinolines. The N- and S-alkylation reactions of 3- and 4-brominated isomers resulted in the same 4- N - and 4- S -methyl derivatives.

Simple synthesis of modafinil derivatives and their biological activity are described. The key synthetic strategies involve substitution and coupling reactions. We determined the anti-inflammatory effects of modafinil derivatives in cultured BV2 cells by measuring the inhibition of nitrite production and expression of iNOS and COX-2 after LPS stimulation. It was found that for sulfide analogues introduction of aliphatic groups on the amide part (compounds 11a–d) resulted in lower anti-inflammatory activity compared with cyclic or aromatic moieties (compounds 11e–k). However, for the sulfoxide analogues, introduction of aliphatic moieties (compounds 12a–d) showed higher anti-inflammatory activity than cyclic or aromatic fragments (compounds 12e–k) in BV-2 microglia cells.

A new triazol-3-one resulted unexpectedly from the reduction reaction of a heterocyclic thioketone using sodium borohydride in pyridine containing a small amount of water. The structure of the new compound was characterised using FT-IR, 1D and 2D NMR, and HRMS spectroscopic methods.

Chemoselective domino ring opening and selective O/S-alkylation of ethers/thioethers over enol C/O alkylation has been observed. Various 2-aryl chromanones/thiochromanones with alkyl/allyl bromides were smoothly converted into the corresponding highly functionalized ethers and thioethers in excellent yields with high selectivity.Graphic abstractAn unusual, chemoselective domino ring opening and selective ether/thioether O/S-alkylation over. An unusual, chemoselective domino ring opening and selective ether/thioether O/S alkylation over enol C/O alkylation has been observed.

The scope of the current work was to synthesize an S-alkylated 1,2,4-triazole-3-thiol derivative. Synthesis was carried out in two steps: in the first step, 4,5-diphenyl-4H-1,2,4-triazole-3-thiol was S-alkylated using a halogenated acetal and cesium carbonate. In the second step, several acetal deprotection procedures were tested, and the aldehyde obtained was isolated as a bisulfite adduct. The structures of the new compounds were characterized by FT-IR, 1D, and 2D NMR spectroscopic methods.

The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.

The novel racemic secondary alcohol (±)-2-{[4-(4-bromophenyl)-5-phenyl-4H-1,2,4-triazol-3-yl]sulfanyl}-1-phenyl-1-ethanol (12) has been successfully synthesized through S-alkylation of 4-(4-bromophenyl)-5-phenyl-4H-1,2,4-triazole-3-thiol (10) in alkaline medium with 2-bromo-1-phenylethanone followed by reduction of the corresponding ketone 11. All the synthesized compounds were characterized by IR, 1D (1H, 13C, DEPT135) and 2D (1H-1H, 1H-13C and 1H-15N) NMR spectroscopy, elemental analysis and HRMS spectrometry.