Wikipedia:Reference desk/Archives/Science/2022 September 7
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September 7
editCan Marker degradation be performed with ozonolysis rather than hexavalent chromium?
editAs a trans person in STEM / going to medical school, the ability of the business decisions of one or two companies to disrupt the hormone supply chain in the US concerns me, so I like to keep abreast of "the state of the art," just in case I have the ability to influence the situation in the distant future. Marker degradation is an old procedure, so I wonder if it's still performed with hexavalent chromium. Maybe I'm searching wrong, but I can't find any new methods that use a substitute for hexavalent chromium, which is environmentally toxic (and just uncool).
What happens if one uses ozonolysis instead of chromic acid to open the cyclic enol ether "furan" ring in the second step of the Marker degradation? The oxidative workup of ozonolysis typically results in carboxylic acids. Can one obtain esters with either the reductive or oxidative workup? The ester group is hydrolyzed in the third and final step of the Marker degradation anyway, with the 16-OH eliminated. Yanping Nora Soong (talk) 17:38, 7 September 2022 (UTC)
- The difference between oxidative and mild reductive workup (dimethyl sulfide) of ozonolysis is whether an alkene carbon that has an H on it becomes an acid as an "over-oxidation" beyond the simple carbonyl (aldehyde). So in the case of the classical Marker degradation, the dihydrofuran ring does not give the opportunity for oxidation beyond the simple carbonyl. There are many alkene-cleavage reactions, several of which are potentially chemoselective for the electron-rich enol alkene rather than other alkenes in the structure. DMacks (talk) 18:29, 7 September 2022 (UTC)
- @Yanping Nora Soong.. Over the years, there have been many process studies to improve the Marker degradation. One 2003 paper doi:10.1021/op0200625 available as a .pdf uses potassium permanganate, for example. Mike Turnbull (talk) 20:20, 7 September 2022 (UTC)