Is there a reaction pathway from chlorophyll a to chlorophyll b in ethanol?
Sigma Aldrich says the following on the product information page for their chlorophyll a - **"**Since this product is sensitive to light, solutions will be unstable when exposed to light. In ethanol solutions, this product is converted to chlorophyll B quickly (approximately 30% decomposition after 30 minutes by HPLC analysis)"
The difference between chlorophyll a and b is a methyl group vs aldehyde on the chlorin ring structure, I don't see a pathway in which this methyl group would be converted to an aldehyde in ethanol?
Am I missing something or is the statement from the product information page incorrect? I understand from reading around chlorophyll-a converts to pheophyton-a, chlorophylide-a and pheophorbide-a quite easily but can't find a pathway to chlorophyll-b.
Thanks for any help.
Link to product information page: https://www.sigmaaldrich.com/deepweb/assets/sigmaaldrich/product/documents/161/075/c5753pis.pdf