This MedLibrary.org supplementary page on Umbelliferone is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
| Umbelliferone | |
|---|---|
 |
|
| IUPAC name | 7-hydroxycoumarin |
| Identifiers | |
| CAS number | 93-35-6 |
| SMILES |
|
| Properties | |
| Molecular formula | C9H6O3 |
| Molar mass | 162.14 g/mol |
| Melting point |
230 °C (decomposes) |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
|
Umbelliferone or 7-hydroxycoumarin is a widespread natural product of the coumarin family. It occurs in many familiar plants from the Apiaceae (Umbelliferae) family such as carrot, coriander and garden angelica, as well plants from other families such as the mouse-ear hawkweed. It is a yellowish-white crystalline solid which has a slight solubility in hot water, but high solubility in ethanol. It absorbs ultraviolet light strongly at several wavelengths. Despite several indications that this chemical is photomutagenic it is used in sunscreens.1
Contents |
Chemical synthesis
Umbelliferone is traditionally synthesized using the Pechmann condensation, from resorcinol and formylacetic acid (generated from malic acid in situ).
A newer synthesis uses methyl propiolate and a palladium catalyst.
Ultraviolet fluorescence
Umbelliferone absorbs strongly at 300, 305 and 325 nm, with log ε values of 3.9, 3.95 and 4.15 respectively, and it fluoresces blue in both ultraviolet and visible light. The powerful absorption at three different wavelengths, coupled with the fact that the energy is dissipated safely as visible light, make umbelliferone a useful sunscreen agent. The absorption changes in alkaline solution, since the phenolic hydroxyl group is deprotonated (pKa = 7.7).
Uses
The ultraviolet activity of umbelliferone lead to its use as a sunscreen agent, and an optical brightener for textiles. It has also been used as a gain medium for dye lasers. Umbelliferone can be used as a fluorescence indicator for metal ions such as copper and calcium. It acts as a pH indicator in the range 6.5-8.9.
Derivatives of umbelliferone
Umbelliferone is the parent compound for a large number of natural products. Herniarin or 7-O-methylumbelliferone (7-methoxycoumarin) occurs in the leaves of water hemp (Eupatorium ayapana) and rupturewort. O-glycosylated derivatives such as skimmin (7-O-β-D-glucopyranosylumbelliferone) occur naturally and are used for the fluorimetric determination of glycoside hydrolase enzymes. Isoprenylated derivatives are also widespread, such as marmin (found in grapefruit skin and in the bark of the Bael tree) and furocoumarins such as marmesin, angelicin and psoralen.
External links
References
 |
This article's citation style may be unclear. The references used may be clearer with a different or consistent style of citation, footnoting, or external linking. (September 2007) |
- F. M. Dean Naturally Occurring Oxygen Ring Compounds, Butterworths, London, 1963.
- J. A. Joule, K. Mills Heterocyclic Chemistry, 4th edition, Blackwell Science, Oxford, UK, 2000.
- Comprehensive Natural Products Chemistry, Volume 2, p 677, D. H. R. Barton, K. Nakanishi, O. Meth-Cohn, editors, Elsevier, Oxford, UK, 1999.
|
|||||
See also
Wikipedia content modification information:
- This page was last modified on 2 September 2008, at 03:14.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Umbelliferone".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.