Chromone and flavanone derivatives were prepared by condensation of the corresponding 2-hydroxyacetophenones (with diethyl oxalate or the appropriate aromatic aldehyde respectively) and cyclisation of the condensation products. Saeyer-Villiger rearrangement of these flavanones, with MCPBA, resulted in expansion of the C-ring. Spectroscopic techniques have been used to establish the regioselectivity of the rearrangement and hence, the identity of the rearranged products as 1,5-benzodioxepan-4-ones. The 1,5-benzodioxepan-4-ones were subjected to detailed ¹H and ¹³C n.m.r. analysis and a combination of low and high resolution mass spectrometry has been used to study the mass fragmentation pathways of these ring-expanded products.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:rhodes/vital:4423 |
| Date | January 1991 |
| Creators | Gelebe, Aifheli Carlson |
| Publisher | Rhodes University, Faculty of Science, Chemistry |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MSc |
| Format | 111 p., pdf |
| Rights | Gelebe, Aifheli Carlson |
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