Investigation of the Diels-Alder cycloadditions of 2(H)-1,4-oxazin-2-ones

Application of 1,4-Oxazinone Precursors to the Construction of Pyridine Derivatives by Tandem Intermolecular Cycloaddition/Cycloreversion

This study reveals a new method for the preparation of 1,4-oxazinone derivatives by Staudinger reductive cyclization of functionalized vinyl azide precursors. The resulting oxazinone derivatives prepared in this manner were intercepted with terminal alkyne substrates through an intermolecular cycloaddition/cycloreversion sequence to afford polysubstituted pyridine products. Alkyne substrates bearing propargyl oxygen substitution showed good regioselectivity in the cycloaddition operation selectively affording 2,4,6-substituted pyridines. Application of this chemistry to the synthesis of an ErbB4 receptor inhibitor is also described.

Synthesis of a pseudo-disaccharide library and its application to the characterisation of the heparanase catalytic site

A novel methodology is described for the efficient and divergent synthesis of pseudodisaccharides, molecules comprising of amino carbasugar analogues linked to natural sugars. The methodology is general and enables the introduction of diversity both at the carbasugar and the natural sugar components of the pseudodisaccharides. Using this approach, a series of pseudodisaccharides are synthesised that mimic the repeating backbone unit of heparan sulfate, and are tested for inhibition of heparanase, a disease-relevant enzyme that hydrolyses heparan sulfate. A new homology model of human heparanase is described based on a family 79 β-glucuronidase. This model is used to postulate a computational rationale for the observed activity of the different pseudodisaccharides and provide valuable information that informs the design of potential inhibitors of this enzyme.

A new, general method for the synthesis of carbasugar-sugar pseudodisaccharides

A general synthetic methodology for the synthesis of sugar-carbasugar pseudodisaccharides is described. The methodology is based on the cycloaddition of pyran-2-ones to vinylated sugars and the subsequent manipulation of the cycloadducts to construct the carbasugar component of the pseudodisaccharide.