Synthesis of chiral zileuton, a potent and selective inhibitor of 5-lipoxygenase

Oxidant- and Catalyst-Free Synthesis of Sulfonated Benzothiophenes via Electrooxidative Tandem Cyclization

A green and practical electrochemical method for the synthesis of C-3-sulfonated benzothiophenes from 2-alkynylthioanisoles and sodium sulfinates was developed under oxidant- and catalyst-free conditions. Moderate to good yields of sulfonated benzothiophenes bearing important and useful functional groups have been achieved at a constant current. Preliminary mechanistic studies indicated a tandem radical addition-cyclization pathway. Moreover, the protocol is easy to scale up and exhibits good reaction efficiency.

Synthesis, X-ray crystal structure, Hirshfeld surface analysis, and molecular docking study of novel inhibitor of hepatitis B: methyl 4-fluoro-3-(morpholinosulfonyl)benzo[b]thiophene-2-carboxylate

A method of 4-fluoro-3-(morpholinosulfonyl)benzo[b]thiophene-2-carboxylate synthesis has been developed and the electronic and spatial structure of a new biologically active molecule has been studied both theoretically and experimentally. The title compound was crystallized from acetonitrile and the single crystal X-ray analysis has revealed that it exists in a monoclinic P2₁/c space group, with one molecule in the asymmetric part of the unit cell. Hirshfeld surface analysis was used to study intermolecular interactions in the crystal. Molecular docking study evaluates the investigated compound as a new potential inhibitor of hepatitis B. Testing for anti-hepatitis B virus activity has shown that this substance demonstrates in vitro nanomolar inhibitory activity against HBV.

Copper-catalyzed synthesis of 2-acylbenzo[b]thiophenes from 3-(2-iodophenyl)-1-arylpropan-1-ones and potassium sulfide under aerobic conditions

A method was developed for the synthesis of 2-acylbenzo[b]thiophenes via a copper-catalyzed sulfuration of 3-(2-iodophenyl)-1-arylpropan-1-ones with K2S under aerobic conditions. Mechanistically, this procedure was proved to involve the formation of a dihydrobenzo[b]thiophene intermediate.

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®.

Unmasking Dipole Character of Acyl Ketene Dithioacetals via a Cascade Reaction with Arynes: Synthesis of Benzo[b]thiophenes

An unusual strategy toward novel substituted benzo[b]thiophenes has been developed. The generation of arynes in the presence of acyl ketene dithioacetals resulted in a cascade reaction involving [3 + 2] cycloaddition, and a dealkylative arylation of a thioether moiety to afford 2,3-disubstuted benzo[b]thiophenes. This route represents an expeditious approach to benzothiophenes that employs acyl ketene dithioacetals as dipoles.

Photoredox-catalyzed cascade annulation of methyl(2-(phenylethynyl)phenyl)sulfanes and methyl(2-(phenylethynyl)phenyl)selanes with sulfonyl chlorides: synthesis of benzothiophenes and benzoselenophenes

A photoredox-catalyzed cascade annulation of methyl(2-(phenylethynyl)phenyl)sulfanes and methyl(2-(phenylethynyl)phenyl)selanes with sulfonyl chlorides was developed.

Three-component 2-aryl substituted benzothiophene formation under transition-metal free conditions

A base-mediated efficient entry for 2-aryl substituted benzothiophene from 2-bromobenzene aldehydes, benzylic esters and elemental sulfur.

One-pot synthesis of 2,3-substituted benzo[b]thiophenes via Cu(i) catalysed intramolecular cyclisation from dithioesters

The novel route involves CuI catalyzed C–S bond formation using dithioesters. This approach is valuable for synthesis of rolaxifene analogues.

Visible light photocatalytic synthesis of benzothiophenes

The photocatalytic reaction of o-methylthio-arenediazonium salts with alkynes yields substituted benzothiophenes regioselectively through a radical annulation process. Green light irradiation of eosin Y initiates the photoredox catalysis. The scope of the reaction was investigated by using various substituted diazonium salts and different alkynes.

CuI/TMEDA-catalyzed annulation of 2-bromo alkynylbenzenes with Na2S: synthesis of benzo[b]thiophenes

A copper-catalyzed thiolation annulation reaction of 2-bromo alkynylbenzenes with sodium sulfide has been developed. In the presence of CuI and TMEDA, a variety of 2-substituted benzo[b]thiophenes were readily prepared in moderate to good yields by the reaction of 2-bromo alkynylbenzenes and Na(2)S·9H(2)O.

From beta-lactams to alpha- and beta-amino acid derived peptides

The potential of beta-lactams as intermediates for the access to alpha- and beta-amino acid-derived peptides is shortly reviewed, with major focus on the technologies developed in our group. The two general strategies lie, on one side, in the oxidative ring expansion of 3-hydroxy beta-lactams to N-carboxy alpha-amino acid anhydrides or Leuch's anhydrides and subsequent coupling with alpha-amino acid esters and, on the other side, in the nucleophilic ring opening of N-Boc-beta-lactams. Both approaches have been successfully applied to the synthesis of alpha,beta-diamino acid, alpha-amino-beta-hydroxy acid, polyhydroxylated alpha-amino acid, alpha,alpha-disubstituted alpha-amino acid, beta-amino acid, beta-amino-alpha-hydroxy acid and beta,beta-disubstituted beta-amino acid derived peptides. Because of the mild reaction conditions needed for the above transformations and the highly stereoselective procedures employed for the construction of the starting beta-lactam ring, the whole process allows the production of optically pure final products.

Effects of zileuton, a new 5-lipoxygenase inhibitor, in experimentally induced colitis in rats

The efficacy of zileuton, a new 5-lipoxygenase inhibitor, was investigated in comparison with sulphasalazine in an experimental model of rat colitis. Under light anaesthesia with ether, male rats were subjected to intracolonic administration of trinitrobenzene sulfonic acid (TNB) in 50% ethanol and were then sacrificed 2, 4 and 7 days after colitis induction. Untreated rats exhibited elevated colonic levels of leukotriene B4 (LTB4) and 6-keto-PGF1 alpha, and an increase in colonic myeloperoxidase (MPO) activity (investigated as an index of leukocyte adhesion and accumulation). Moreover, ulceration and inflammation of the distal colon with formation of granuloma and pathologic connections were observed. Treated rats received zileuton or sulphasalazine (50 mg/kg per os twice a day) 24 h before the induction of colitis until they were sacrificed. Treatment with the specific 5-lipoxygenase inhibitor, zileuton, resulted in significant reductions of colonic leukotriene B4 and 6-keto-PGF1 alpha synthesis, macroscopic and histological colonic damage and colonic inflammation as assessed by the measurement of MPO activity. In contrast, sulphasalazine had a lower effect than zileuton on LTB4 and MPO levels (p < 0.05), while it was able to reduce colonic damage and 6-keto-PGF1 alpha levels as well as zileuton. This study shows, therefore, that zileuton is effective in attenuating the lesions in an experimental model of colitis. Furthermore, the results are consistent with the hypothesis that leukotrienes play an important role in the pathogenesis of intestinal bowel diseases (IBD).