A new ionic, water-soluble scavenger for acyl chlorides, 1-(2-aminoethyl)pyridinium bromide (1), has been investigated. Compound 1 was used for the rapid and simple purification of a series of benzamides and sulfonamides (Table) obtained by solution-phase synthesis from the corresponding amines (Scheme). The inexpensive scavenger, which can be prepared on large scale, was shown to readily 'eliminate' excess acyl chlorides (reagent) by simple aqueous extraction. The amides purified in this way were obtained in excellent yields and purities (Table), which makes 1 a versatile new reagent, especially for the combinatorial solution-phase synthesis of amide libraries.Introduction. -Solution-phase combinatorial chemistry for library generation has been receiving increased attention as a powerful tool for lead discovery and optimization in drug development [1]. Solution-phase synthetic techniques offer many advantages over solid-phase approaches such as unlimited scale, simple manipulation, and cost effectiveness. However, with solution-phase syntheses, the rapid purification or isolation of desired compound from a reaction mixture is difficult, and represents the 'bottleneck' in the synthetic process.Recently, polymer-supported scavengers have been developed for compound purification in solution-phase combinatorial chemistry [2]. These scavengers allow the removal of excess reagents and side products by simple filtration, but low loading capacity and high costs have, so far, limited their application for large-scale library preparation. Although several high-loading solid scavenger reagents have been developed, they suffer from slow exchange at the solid -liquid interface [3]. An efficient solution to these problems is replacement of the polymer-supported scavenger with smallmolecule reagents such as Girard's reagent T [4], N-methyltris(2-aminoethyl)amine [5], N-Boc-iminodiacetic anhydride [6], and potassium sarcosinate [7] to generate water-soluble byproducts, which can be separated, together with the excess scavengers, from the products by liquid -liquid extraction.Recently, Song and co-workers [8] reported an amino-functionalized ionic liquid, i.e., 1-aminoethyl-3-methylimidazolium hexafluorophosphate ([2-aemim] [PF 6 ]), as an electrophile scavenger for solution-phase synthesis; the scavenging products were separated by extraction with the ionic liquid [bmim] [PF 6 ].Herein, we describe the application of the practical, ionic, water-soluble scavenger 1-(2-aminoethyl)pyridinium bromide (1) for the solution-phase synthesis of libraries of amides and sulfonamides.