Rotundon

Structural formula
General
Surname	Rotundon
other names	(3 S , 5 R , 8 S ) -3,4,5,6,7,8-hexahydro-3 α , 8 α -dimethyl-5 α - (1-methylethenyl) azulen-1 (2 H ) -one
Molecular formula	C 15 H 22 O
External identifiers / databases
CAS number 18374-76-0 PubChem 5321003 Wikidata Q15424773
properties
Molar mass	218.33 g mol −1
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Rotundon is an oxygen-containing bicyclic sesquiterpene ketone from the family of Guajane . It is an important flavoring of the Syrah grape variety.

Occurrence

• 

  Syrah grapes

• 

  pepper

• 

  rosemary

• 

  basil

• 

  oregano

• 

  thyme

• 

  marjoram

In addition to wine , rotundon also occurs as a flavoring in pepper . Rotundon is also the key compound for the aroma in black and white pepper. In addition, rotundon is also found in the spices basil , thyme , oregano , rosemary and marjoram .

Rotundon content in various natural products
White pepper	2025 µg kg −1	Syrah grapes	0.62 µg kg −1
Black pepper	1200 µg kg −1	marjoram	208 µg kg −1
Wine ( shiraz )	0.15 µg kg −1	oregano	1 µg kg −1
Geraniums	25 µg kg −1	Atriplex cinerea	37 µg kg −1
Tuberous Zypergrass	920 µg kg −1	basil	4 µg kg −1
rosemary	86 µg kg −1	thyme	5 µg kg −1

properties

The peppery note of the rotundon has an odor threshold of 16 ng · l ⁻¹ in red wine and 8 ng · l ⁻¹ in water. The rotundon content is determined analytically by gas chromatography and mass spectrometry . In some cases, olfactometry is also used.

synthesis

The basis is guaiacol , which is obtained from the oil of the guaiac tree . The guaiacol is first acetylated. This is followed by an allyl oxidation. Finally, the rotundon is obtained by acetate pyrolysis and can then be purified by column chromatography.

Individual evidence

1. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
2. ↑ ^{a b} Entry on Rotundon. In: Römpp Online . Georg Thieme Verlag, accessed on February 9, 2018.
3. ^ Fischer, Markus, Glomb, Marcus A .: Modern food chemistry . 1st edition. Behr's, Hamburg 2015, ISBN 978-3-89947-864-8 .
4. ↑ ^{a b c d} Claudia Wood, Tracey E. Siebert, Mango Parker, Dimitra L. Capone, Gordon M. Elsey: From Wine to Pepper: Rotundone, an Obscure Sesquiterpene, Is a Potent Spicy Aroma Compound . In: Journal of Agricultural and Food Chemistry . tape 56 , no. 10 , May 1, 2008, ISSN  0021-8561 , p. 3738-3744 , doi : 10.1021 / jf800183k .
5. ↑ Schore, Neil Eric, 1948-: Organic chemistry: structure and function . Seventh ed. New York, NY 2014, ISBN 978-1-4641-2027-5 .