Scavenger reagents

An important breakthrough in that respect was the use of soHd-phase organic synthesis (SPOS) where the attachment of the substrate to an insoluble support allowed for easy workup (filtration) and for rapid generation of products via split-mix procedures [1,2]. An important subsequent development consisted of the immobihzation of reagents, scavengers and catalysts. This technique, coined polymer-assisted solution phase chemistry (PASP), allowed solution phase synthesis of compoimds, yet still enjoying the bene-... 

Recently, a novel method for the synthesis of a library of substituted prolines with microwave technology [95] has been described. In the first step, 1 equivalent of an amine is added to 1.1 equivalents of an aldehyde in 1,2-dichloroethane (DCE), with subsequent irradiation at 180 °C for 2 min. In the second step, 0.85 equivalents of the maleimide are added and the resulting solution is heated at 180 °C for an additional 5 min. This methodology allowed the production of a solution-phase library of 800 compounds with a crude purity between 65 and 82% (Scheme 9.45). The compounds were purified by solid-supported reagent scavenging to afford the final products with a purity between 90 and 98% and in 79-85 % yield [96]. 

Baxendale IR, Ley SV, Smith CD, Tranmer GK (2006d) A flow reactor process for the synthesis of peptides utilizing immobilized reagents, scavengers and catch and release protocols. J Chem Soc Chem Commun 4835-4837... 

Bhattacharyya SJ (2004) New developments in polymer-supported reagents, scavengers and catalysts for organic synthesis. Curr Opin Drug Discov De-vel 7 752-764... 

Possible use of supported reagents-scavenger Simultaneous reaction and filtration Byproducts are retained on the solid phase ... 

An increasing number of groups are generating libraries in which parallel reactions occur in solution. Until very recently, solution-based syntheses were primarily utilized for the preparation of simple structures. However, the introduction of resin-bound reagents, scavenger resins, and parallel purification schemes is allowing more complex chemistries to be performed in parallel solution format. 

Use Oxidizing agent, depolarizer in dry cell batteries (African and synthetic types only), pyrotechnics, matches, etc., catalyst, laboratory reagent, scavenger and decolorizer, textile dyeing, source of metallic manganese (as pyrolusite). 

In this chapter we have described the multistep application of supported reagents, scavengers, and catch-and-release techniques to the construction of various natural products and natural product-like libraries of compounds. These methods of immobilization can aid considerably the rapid optimization of complex chemical transformations. They avoid or minimize the need for more time-intensive skill-based workup procedures, such as chromatography, distillation, and crystallization, and are therefore valuable new tools to add to the repertoire of the synthesis chemist. 

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