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Tetrasubstituted furans and their derivatives represent a versatile class of important heterocyclic frameworks widely distributed in natural products. These scaffolds also demonstrate significant potential in pharmaceutical chemistry, materials science, and organic synthesis methodologies. In this study, we successfully established a synergistic catalytic system utilizing benzoylacetonitriles, aldehydes, and benzoyl chlorides as substrates, facilitated by tributylphosphine and immobilized lipase (Novozym 435), to achieve efficient synthesis of cyano-containing tetrasubstituted furans. Under optimized conditions, we obtained a series of target products exhibiting exceptional substrate tolerance with good to excellent isolated yields ranging from 80% to 94%. Additionally, we proposed a reasonable reaction mechanism and verified it through controlled experiments. This methodology not only expands the synthetic utility of lipase in non-natural transformations but also establishes a paradigm of green chemistry for the construction of tetrasubstituted furans.

Asymmetric synthesis of chiral hydroxysulfones, key pharmaceutical intermediates, is challenging. We report an efficient synthesis from readily available materials via a one-pot photo-biocatalytic cascade reaction in aqueous conditions, utilizing visible light as an energy source. This sustainable process achieves up to 84% yields and 99% ee. Engineered ketoreductase produces R-configured products with high conversion and enantioselectivity across diverse substrates. Molecular dynamics (MD) simulations explored enzyme–substrate interactions and their influence on reaction activity and stereoselectivity.

An intriguing DABCO-catalyzed and DBU-promoted one-pot synthesis of an important class of (2-hydroxyaryl)pyridine derivatives bearing a carboxylate or a nitrile group suitably placed at C3 position of the aza-ring has been achieved in acceptable chemical yields with a broad functional group tolerance. This sequential C–C/C–N bond making process proceeds through a regioselective allylic alkylation/aza-Michael reaction between MBH carbonates derived from an acrylate/acrylonitrile and N -sulfonyl ketimines as C,N-binucleophiles catalyzed by DABCO, followed by elimination of SO 2 under the influence of base and subsequent aromatization in an open atmosphere.

Diaryl urea-based compounds have attracted the attention of many researchers due to their potential as anticancer agents. Following our previous study on a series of diaryl urea compounds and implementation of the obtained structure activity relationship (SAR) analysis, a new set of derivatives were designed and synthesized. The synthesized compounds were subjected to evaluation for their in vitro antiproliferative activities against A549 and HT-29 cell lines. Among all, 6a emerged as the most potent antiproliferative agent with an IC 50 value of 15.28 and 2.566 µM against HT-29 and A549 cells, respectively. Comparing the activity of the newly designed and synthesized diaryl urea compounds 4a-b and 6a-e with those for the previously reported compounds 8a-b and 9a-f confirmed the importance of the substitution of amide groups instead of ester between the central and distal benzene rings of diaryl urea scaffold. The results of current study revealed that the substitution of proximal and distal benzene rings with chlorine and methyl groups, alongside the linear extension of molecules through the introduction of a methylene spacer group could enhance antiproliferative activity, which is in agreement with previously reported SAR analysis. Molecular docking simulations demonstrated that all designed compounds exhibit binding affinity to VEGFR-2 similar to that observed experimentally for sorafenib. The findings of this study may offer valuable insights for the further development of diaryl urea-based anticancer agents. Graphical Abstract

Herein, we describe a novel approach for the practical synthesis of tetrasubstituted thiophenes 8 . The developed method was particularly used for the facile preparation of thienyl heterocycles 8 . The mechanism for this reaction is based on the formation of a sulfur ylide-like intermediate. It was clearly suggested by (i) the intramolecular cyclization of ketene N,S -acetals 7 to the corresponding thiophenes 8 , (ii) 1 H NMR studies of Meldrum’s acid-substituted aminothioacetals 9 , and (iii) substitution studies of the methoxy group on Meldrum’s acid containing N,S -acetals 9b . Notably, in terms of structural effects on the reactivity and stability of sulfur ylide-like intermediates, 2-pyridyl substituted compound 7a exhibited superior properties over those of others.

1-Ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][OTf]) is an efficient co-solvent and co-promoter for one-pot sequential glycosylation with the combined use of thioglycosides and trichloroacetimidates (or N-phenyltrifluoroacetimidates) donors at room temperature. One-pot glycosylation is efficient for the synthesis of triterpenoid saponins with the combined use of N-phenyltrifluoroacetimidate donors and 2-methyl-5-tert-butylphenyl (Mbp) thioglycoside donors in [emim][OTf].

This chapter contains sections titled: Introduction New Catalytic Systems Biomass Conversions Summary References

This chapter contains sections titled: Introduction Development of Heterogeneous Catalysts for PKR Transition Metal Nanoparticle Catalyst Bimetallic Nanoparticle Catalysts Sequential Action of Two Different Catalysts in One‐Pot Reactions Conclusion References

The direct formation of (hetero)biaryls from readily available (hetero)aryl halides under mild reaction conditions can be efficiently achieved through the Masuda borylation–Suzuki coupling (MBSC) sequence. The MBSC sequence catenates Pd-catalyzed Masuda borylation and Suzuki coupling into a one-pot process, giving access to diverse symmetrically and unsymmetrically substituted scaffolds. (Hetero)biaryls are ubiquitous structural motifs that appear in natural products, pharmaceutically relevant scaffolds, functional dyes, and several other structures. This review summarizes the development of the MBSC sequence and its improvements over the past two decades.

Repeats of the disaccharide unit N-acetyllactosamine (LacNAc) occur as type 1 (Galβ1, 3GlcNAc) and type 2 (Galβ1, 4GlcNAc) glycosylation motifs on glycoproteins and glycolipids. The LacNAc motif acts as binding ligand for lectins and is involved in many biological recognition events. To the best of our knowledge, we present, for the first time, the synthesis of LacNAc type 1 oligomers using recombinant β1,3-galactosyltransferase from Escherichia coli and β1,3-N-acetylglucosaminyltranferase from Helicobacter pylori. Tetrasaccharide glycans presenting LacNAc type 1 repeats or LacNAc type 1 at the reducing or non-reducing end, respectively, were conjugated to bovine serum albumin as a protein scaffold by squarate linker chemistry. The resulting multivalent LacNAc type 1 presenting neo-glycoproteins were further studied for specific binding of the tumor-associated human galectin 3 (Gal-3) and its truncated counterpart Gal-3∆ in an enzyme-linked lectin assay (ELLA). We observed a significantly increased affinity of Gal-3∆ towards the multivalent neo-glycoprotein presenting LacNAc type 1 repeating units. This is the first evidence for differences in glycan selectivity of Gal-3∆ and Gal-3 and may be further utilized for tracing Gal-3∆ during tumor progression and therapy.