Title: flavans
Long Title: IUPAC Gold Book - flavans
DOI: 10.1351/goldbook.09967
Status: current

Definition
Flavans are compounds with a 2-phenyl-3,4-dihydro-2\(H\)-1-benzopyran skeleton (1 in flavonoids), that may be substituted, and include flavan-3-ols (compounds derived from 2-phenyl-3,4-dihydro-2\(H\)-1-benzopyran-3-ol skeleton 2) and flavan-4-ones (compounds derived from 2-phenyl-2,3-dihydro-4\(H\)-1-benzopyran-4-one skeleton 3), which are generically designated as flavanols and flavanones, respectively. Compounds derived from 2-phenyl-3,4-dihydro-2\(H\)-1-benzopyran-3,4-diol skeleton 4 are flavan-3,4-diols, designated leukoanthocyanidins because these colourless compounds have their structure derived from that of an anthocyanidin, specifically they are dehydronated 3,4-dihydroxy-1,2,3,4-tetrahydroanthocyanidins.

Source
- PAC, 2018, 90, 1429. 'Nomenclature of flavonoids (IUPAC Recommendations 2017)' on page 1432 (https://doi.org/10.1515/pac-2013-0919)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/09967/html
- json: https://goldbook.iupac.org/terms/view/09967/json
- xml: https://goldbook.iupac.org/terms/view/09967/xml

Citation: Citation: 'flavans' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.09967
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Accessed: 2026-06-13T13:07:20+00:00