Synlett

Solid-phase synthesis of dihydropyrimidones via N-acyliminium ion-based α-ureidoalkylations

MG Valverde, D Dallinger, CO Kappe

Index: Valverde, Maria Garcia; Dallinger, Doris; Kappe, C. Oliver Synlett, 2001 , # 6 p. 741 - 744

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Citation Number: 29

Abstract

Abstract: The synthesis of 4-aryl-2-(thioxo) oxo-3, 4-dihydropyrimidine-5-carboxylic acids is reported using two orthogonal solidphase variations of the Biginelli condensation. In the first method, polymer-bound b-ketoesters are treated with aromatic aldehydes and urea under acidic conditions. The transient N-acyliminium ion that is initially formed from the aldehyde and urea precursors, is then intercepted by the resin-bound b-ketoesters. In an alternative ...