Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A Fragrance That Breaks the Rules

07.12.2012
Synthesis of a Spirocyclic Seco Structure of the Principal Vetiver Odorant Khusimone

Approximately one third of all fragrances on the market contain vetiver oil as a key ingredient, for which no synthetic odorant is commercially available. Instead it has to be distilled from the dried roots of vetiver grass.

To find out about the structural requirements of vetiver odorants, researchers in Switzerland devised a synthesis to a 7,8-seco-khusimone, which still contained all the structural features held responsible for the vetiver odour. As they report in the European Journal of Organic Chemistry, however, the final product displayed none of the expected olfactory characteristics, thus proving the vetiver rule wrong.

Vetiver oil has a distinct and characteristic suave and sweet woody-earthy odour with additional green grapefruit and rhubarb-type facets. In perfumery it is often used to provide the woody base note in combination with rather inexpensive bergamot oil, or its synthetic counterparts, which provides a fresh citrus component.

Currently, there is no synthetic vetiver perfumery material available commercially. This lack of availability is partially due to the complex sesquiterpene nature of its constituents, and partially due to the lack of consensus as to which constituents contribute to its characteristic odour. One component for which there is consensus is (¨C)-khusimone, which forms only up to 2% of the essential oil, but does present a typical vetiver odour and is, so far, the only genuine natural lead structure.

Syntheses of related structures led to the development of a vetiver rule, which postulates that the woody odour of vetiver is a result of the presence of an ¦Á-branched carbonyl osmophore at a specific distance from a bulky group, with an overall dimension of 13¨C15 carbon atoms. Philip Kraft and Natacha Denizot (Givaudan, Switzerland) thus decided to apply this vetiver rule to the genuine lead structure khusimone itself in order to design a new vetiver odorant with even improved olfactory properties, and in addition an easier synthetic access.

The target structure, 7,8-seco-khusimone, was obtained as a mixture of diastereomers in a 10-step sequence starting from commercially available allyl alcohol and isovaleric acid. A key advantage of the sequence is that it fairly easily allows further modifications of the target structure. Although the desired compound was synthesised successfully it was 10 times less intense than (¨C)-khusimone and displayed a floral, rosy, green, germanium-like odour with no woody or vetiver character. Kraft and Denizot, therefore, conclude that the vetiver rule has been proved wrong, or at least that the structural requirements are more complex than first suggested.
Author: Philip Kraft, Givaudan Schweiz AG, D¨¹bendorf (Switzerland), mailto:philip.kraft@givaudan.com
Title: Synthesis of a Spirocyclic Seco Structure of the Principal Vetiver Odorant Khusimone

European Journal of Organic Chemistry , 2013, No. 1, Permalink to the article: http://dx.doi.org/10.1002/ejoc.201201318

Philip Kraft | Wiley-VCH
Further information:
http://www.wiley-vch.de

More articles from Life Sciences:

nachricht How to become a T follicular helper cell
31.07.2015 | La Jolla Institute for Allergy and Immunology

nachricht Heating and cooling with light leads to ultrafast DNA diagnostics
31.07.2015 | University of California - Berkeley

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum Matter Stuck in Unrest

Using ultracold atoms trapped in light crystals, scientists from the MPQ, LMU, and the Weizmann Institute observe a novel state of matter that never thermalizes.

What happens if one mixes cold and hot water? After some initial dynamics, one is left with lukewarm water—the system has thermalized to a new thermal...

Im Focus: On the crest of the wave: Electronics on a time scale shorter than a cycle of light

Physicists from Regensburg and Marburg, Germany have succeeded in taking a slow-motion movie of speeding electrons in a solid driven by a strong light wave. In the process, they have unraveled a novel quantum phenomenon, which will be reported in the forthcoming edition of Nature.

The advent of ever faster electronics featuring clock rates up to the multiple-gigahertz range has revolutionized our day-to-day life. Researchers and...

Im Focus: Superfast fluorescence sets new speed record

Plasmonic device has speed and efficiency to serve optical computers

Researchers have developed an ultrafast light-emitting device that can flip on and off 90 billion times a second and could form the basis of optical computing.

Im Focus: Unlocking the rice immune system

Joint BioEnergy Institute study identifies bacterial protein that is key to protecting rice against bacterial blight

A bacterial signal that when recognized by rice plants enables the plants to resist a devastating blight disease has been identified by a multi-national team...

Im Focus: Smarter window materials can control light and energy

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Euro Bio-inspired - International Conference and Exhibition on Bio-inspired Materials

23.07.2015 | Event News

Clash of Realities – International Conference on the Art, Technology and Theory of Digital Games

10.07.2015 | Event News

World Conference on Regenerative Medicine in Leipzig: Last chance to submit abstracts until 2 July

25.06.2015 | Event News

 
Latest News

Tool making and additive technology exhibition: Fraunhofer IPT at Formnext

31.07.2015 | Trade Fair News

First Siemens-built Thameslink train arrives in London

31.07.2015 | Transportation and Logistics

California 'rain debt' equal to average full year of precipitation

31.07.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>