Investigations in combinatorial and solid phase organic chemistry

Abstract

The insecticide industry faces increasing challenges from insect resistance to growing concerns over environmental issues. Synthesis of analogues of the insect moulting hormone, 20-hydroxyecdysone by solid phase methods was targeted as potential entry into new insecticide chemistry. The synthetic route utilised readily available 20-hydroxyecdysone that was converted by oxidative cleavage into poststerone that underwent solid phase attachment and either reductive amination or hydrazone formation. In the course of the reductive amination, a stereoselective reduction of the C²⁰ ketone was used to generate dihydropoststerone. Synthesis of acetals on the 2,3 A-ring diol was carried out. Little biological activity over the native poststerone was identified.

Intermolecular radical additions to arenes are generally inefficient due to the large number of side products generated. Synthesis of three precursors for intramolecular radical addition of aryl radicals to arenes was accomplished. Two precursors were protected as model benzyl ethers and the third was immobilised on polystyrene resin. Each precursor underwent radical cyclisation and the results showed that solid phase immobilisation favoured intramolecular cyclisation over radical quench.

The use of high resolution Magic Angle Spinning (MAS) NMR to follow solid phase reactions was demonstrated. The preparation of resins loaded with the Wang linker and a short resin-based synthesis of alkenes was monitored by NMR.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata