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DOI: 10.1055/a-2359-8813
Selective Synthesis of Deuterated cis- and trans-Isohumulones and trans-Isohumulinones
We gratefully thank Merck & Co, Inc, Process Research & Development, Rahway, NJ, USA for financial support.


Abstract
Deuterated isohumulones can be prepared directly from humulones by an acyloin ring contraction under either magnesium-catalyzed basic conditions or by photochemical-induced reactions in deuterated solvents. Reactions of humulones with biphasic methylene chloride/aqueous NaOD and MgSO4 in D2O leads to stereoselective formation of cis-d 3-isohumulones (cis/trans ratio of 82:18) as the magnesium salts in yields of 71–83%. Greater than 95% incorporation of three deuterons is observed at the C5 position of the pentenone ring and the methylene position of the C4 acyl group. Photochemical isomerization with a 400 nm blue LED source enables stereospecific formation of deuterated trans-isohumulones in 36–82% yield with greater than 95% incorporation of deuterium at the C5 ring position. Oxidation of humulones with cumene hydroperoxide in basic D2O gives isohumulinones with partial 55–73% incorporation of deuterium due to keto–enol isomerization of the methylene substituent of the C4 acyl group. The structural identities of the deuterated products are determined by a combination of negative-mode electrospray mass spectrometry (MS-ESI–) and 2D heteronuclear proton–carbon HMQC NMR analysis.
Key words
humulone - isohumulone - humulinone - deuteration - hydrogen–deuterium exchange - isotopic labeling - heteronuclear proton–carbon NMRSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/a-2359-8813
- Supporting Information
Publikationsverlauf
Eingereicht: 16. Februar 2024
Angenommen nach Revision: 03. Juli 2024
Accepted Manuscript online:
03. Juli 2024
Artikel online veröffentlicht:
22. Juli 2024
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