Development of a Chemical Toolkit for the Modulation of Cellular Formaldehyde

Formaldehyde (HCHO) is a reactive carbonyl species generated by a plethora of biological processes, such as histone demethylation, cellular oxidation, and metabolism. At low concentrations, HCHO has been reported to play important roles in epigenetic regulation and the 1-C cycle, but dysregulation of HCHO is linked with pathology and disease. Hence, it is essential to develop methods for detecting and modulating cellular HCHO to elucidate the true “friend or foe” nature of biological HCHO. This thesis describes the development of a four-pronged approach to quantify and modulate HCHO in aqueous solutions, using a variety of chemical and analytical techniques.

A library of small molecule 2-aza-Cope HCHO scavengers were synthesised to investigate the effects of synthetic modification to either the 2-aza-Cope trigger or the benzyl scaffold on scavenging ability through NMR spectroscopy. Substitution on the homoallylamine trigger was found to increase rate of reaction but was also associated with a critical loss of selectivity. Installation of trifluoromethyl and nitro groups on the benzyl scaffolds elicited a decrease in scavenging rate, while methoxy and hydroxyl substituents improved reaction times. Interestingly, all probes synthesised demonstrated comparable reactivity with glyoxylic acid as with HCHO, revealing a key opportunity to repurpose these probes as glyoxylate scavengers. The synthesised probes were then used to develop a HCHO detection method using headspace and immersive solid-phase microextraction gas chromatography/mass spectrometry. Scavenging of HCHO and glyoxylic acid by the 2-aza-Cope was also confirmed by fluorescence assays using a synthesised coumarin-based sensor.

A first generation HCHO donor bearing a light-sensitive trigger was also synthesised and validated as a HCHO releaser by ¹H NMR spectroscopy. The mechanism of HCHO release was also proposed.