Synthesis of 6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles by azomethine imine-alkyne cycloadditions using immobilized Cu(II)-catalysts

Štanfel, Urša (author), Slapšak, Dejan (author), Grošelj, Uroš (author), Požgan, Franc (author), Štefane, Bogdan (author), Svete, Jurij (author)

A series of 12 silica gel-bound enaminones and their Cu(II) complexes were prepared and tested for their suitability as heterogeneous catalysts in azomethine imine-alkyne cycloadditions (CuAIAC). Immobilized Cu(II)–enaminone complexes showed promising catalytic activity in the CuAIAC reaction, but these new catalysts suffered from poor reusability. This was not due to the decoordination of copper ions, as the use of enaminone ligands with additional complexation sites resulted in negligible improvement. On the other hand, reusability was improved by the use of 4-aminobenzoic acid linker, attached to 3-aminopropyl silica gel via an amide bond to the enaminone over the more hydrolytically stable N-arylenamine C-N bond. The study showed that silica gelbound Cu(II)–enaminone complexes are readily available and suitable heterogeneous catalysts for the synthesis of 6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazoles.

• Language: English
• Keywords: 1, 3-dipolar cycloadditions, 2, 3-dihydropyrazolo[1, 2-a]pyrazoles, copper-catalyzed azomethine imine-alkyne cycloaddition (CuAIAC), azomethine imines, ynones
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 18 str.
• Numbering: Vol. 26, iss. 2, art. 400
• PID: 20.500.12556/RUL-134926
• UDC: 547.78
• ISSN on article: 1420-3049
• DOI: 10.3390/molecules26020400
• COBISS.SI-ID: 46951171
• Publication date in RUL: 11.02.2022

Record is a part of a journal

• Title: Molecules
• Shortened title: Molecules
• Publisher: MDPI
• ISSN: 1420-3049
• COBISS.SI-ID: 18462981

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 13.01.2021

Secondary language

• Language: Slovenian
• Keywords: 1, 3-dipolarne cikloadicije, 2, 3-dihidropirazolo[1, 2-a]pirazoli, z bakrom katalizirane cikloadicije, CuAIAC, azometin imini, inoni, alkini

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0179
• Name: Napredna organska sinteza in kataliza