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Paul E Brennan

Publications and source records attributed to Paul E Brennan.

4 recordsLinked to original sources

Synthesis of carbohydrate derivatives using solid-phase work-up and scavenging techniques.

Methods to allow the clean preparation of oligosaccharides were investigated using techniques that do not require conventional column chromatography or an aqueous work-up. The route was designed to provide rapid access to oligosaccharides and is suitable for automation and parallel library formation. The research has focused on the glycosidations of a range of glycosyl acceptors with various selenophenyl glycosyl donors using iodine as an activator in the presence of DTBMP, a hindered organic base. Hydroxyl-containing contaminants were removed by scavenging with polymer-supported tosyl chloride.

Carbohydrate Sequence↗

Combinatorial synthetic design. Solution and polymer-supported synthesis of heterocycles via intramolecular aza Diels-Alder and imino alcohol cyclizations.

A flexible synthetic strategy for combinatorial chemical applications has been developed on the basis of an aldehyde-bridge-alkene motif as the key component in several intramolecular cycloaddition reactions. This strategy was explored most extensively with the formal aza Diels-Alder cyclization, which affords a series of configurationally and functionally diverse heterocyclic compounds. The substrates included substituted salicylaldehydes, glyoxylic esters and amides, and N-acyl-alpha-aminoaldehydes; all reacted with a variety of anilines to yield different tetrahydroquinoline products. The cyclization of the aminoaldehydes was also translated from solution and optimized for solid phase. The stepwise mechanism of this cycloaddition suggested that the cationic intermediate from initial ring closure could be trapped by a variety of nucleophiles. This suggestion was confirmed by cyclization of amino alcohols and related compounds.

Alcohols↗