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Support of Synthesis
J. Comb. Chem. 5, 465-471 (2003)
Cellulose Beads: a New Versatile Solid Support for Microwave-Assisted Synthesis. Preparation of Pyrazole and Isoxazole Libraries
Lidia De Luca, Giampaolo Giacomelli, Andrea Porcheddu,* Margherita Salaris, and
Maurizio Taddei
*) Dipartimento di Chimica, UniVersita` degli Studi di Sassari, Via Vienna 2, I-07100 Sassari, Italy
Dipartimento Farmaco Chimico Tecnologico, UniVersita` degli Studi di Siena, Via Aldo Moro,
I-53100 Siena, Italy
Summary
The synthesis of libraries of substituted pyrazoles and isoxazoles has been developed via in situ generation
of polymer-bound enaminones. The synthetic protocol makes use of commercially available aniline
cellulose (IONTOSORB AV), a low-cost and versatile biopolymer, under very mild conditions. This new support allowed us to carry out
reactions in polar solvents under both conventional heating and MW irradiation without degradation of the
polymer. The reaction between cellulose (PERLOZA MT 100)-bound enaminone and hydroxylamine or hydrazines to afford the
target heterocycles in high yields directly in solution is the key step. The support can be conveniently recycled.
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