The Diels-Alder reaction between isoprene and methyl acrylate over several zeolites was thoroughly investigated. ZSM-5 zeolites provided the highest productivity in methyl 4-methylcyclohex-3-enecarboxylate isomer, achieving 0.219 mmol product per mmol H in 1 hour. In addition, this study highlights the influence of ZSM-5 zeolite's Brønsted acidity and crystal size on its performance in the Diels-Alder reaction. An optimal configuration between the two reactants within the medium-pore-sized ZSM-5 framework is obtained, thus suggesting the presence of a confinement effect.
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http://dx.doi.org/10.1002/cplu.201300157 | DOI Listing |
Bioorg Chem
January 2025
N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Lavrentyev Avenue 9, Novosibirsk 630090, Russia. Electronic address:
Eudesmane-type sesquiterpene lactone isoalantolactone 1 is of great interest due to its availability, biological activity and synthetic application. Respective series of original spirocyclic (11S,5') (1,2,3-triazoline-eudesma-4,15-enolides) and (11S)-aziridine-eudesma-4,15-enolides were efficiently synthesized via a chemoselective 1,3-dipolar cycloaddition reaction of organic azides to the exocyclic double bond of the lactone ring of isoalantolactone or 13E-(aryl)isoalantolactones by heating in DMF or toluene. The thermal reactions of isoalantolactone with benzyl azide, 2-azidoethanol, or n-butyl azide in 2-methoxyethanol afforded 13-(alkyamino)isoalantolactones formed as a mixture of (Z) and (E)-isomers.
View Article and Find Full Text PDFBioorg Chem
January 2025
Department of Chemistry, Faculty of Science, Taibah University, Al-Madinah Al-Munawarah 30002 Saudi Arabia. Electronic address:
The discovery of novel anti-cancer drugs motivated us to synthesize a new series of triple 1,2,3-triazole-based arm scaffolds featuring distinct un functionalized alkyl and/or aryl side chains with possible anti-cancer action using the click chemistry approach under both conventional and green microwave irradiation (MWI) methods. The Cu(I) catalyzed cycloaddition reaction of targeted tris-alkyne with un functionalized aliphatic and aromatic azides has been adopted as an efficient approach for synthesizing the desired click adducts. Microwave irradiation improved the synthetic processes, resulting in higher yields and faster reaction times.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
Despite tremendous progress of dienamine catalysis along with its application in enantioselective synthesis over nearly two decades, certain limitations, especially with respect to the regioselectivity in the dienamine generation step, continue to persist. To overcome these shortcomings of classical dienamine catalysis, we now introduce the concept of alkoxy-directed dienamine catalysis and apply it to the enantioselective arene construction by desymmetrizing -enediones through [4 + 2]-cycloaddition. Catalyzed by a diphenylprolinol silyl ether, this reaction utilizes γ-alkoxy α,β-unsaturated aldehydes as the substrate and proceeds in a highly regioselective fashion through the intermediacy of δ-alkoxy dienamine.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Materials Research Institute, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico.
Since its conceptualization, click chemistry in all its variants has proven to be a superior synthesis protocol, compared to conventional methods, for forming new covalent bonds under mild conditions, orthogonally, and with high yields. If a term like reactive resilience could be established, click reactions would be good examples, as they perform better under increasingly challenging conditions. Particularly, highly hindered couplings that perform poorly with conventional chemistry protocols-such as those used to conjugate biomacromolecules (e.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Institute of Chemistry, Federal University of Uberlândia, Uberlândia 38400-902, Brazil.
Cellulose tosylate (MCC-Tos) is a key derivative for surface modification and a crucial precursor for cellulose compatibilization in click reactions, enabling its functionalization for advanced applications. Replacing tosyl groups with alkyne groups broadens cellulose's potential in biocompatible reactions, such as thiol-yne click chemistry and protein/enzyme immobilization. To achieve this, we optimized the heterogeneous synthesis of MCC-Tos using a Doehlert matrix statistical design, evaluating the influence and interaction of the reaction conditions.
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