Olfactory Chemistry: Lactones- Peaches and Cream

“I’ll take cream in that” is a common phrase when talking about the way you like your coffee or tea. When a perfumer wants to add creaminess to a perfume they are composing they mostly turn to one class of compounds called lactones. The names of these compounds are derived from the Latin phrase for milk, lac lactis.

esterlactone

Lactones were discovered in the early 1900’s as chemists found a way to cyclize esters. A beneficial side effect of this cyclization was it took esters that couldn’t be used for perfumery because they were so short lasting because of their volatility. The cyclic form could last on skin for hours, even days in some cases. The very simple case is shown above as methyl propionate is the ester on the left and when it is cyclized it is called gamma-Butyrolactone. Lactones are also found naturally, most prominently in tuberose. There are so many lactones in tuberose new ones have been discovered as recently as 2004.

peach coconut lactone

Almost from the moment they were discovered the lactones became key components of perfumes. One of the most influential, in perfumery, is one called Peach Lactone. Chemically you can see it is an analog of the gamma-lactone with a long carbon chain attached to it and is called gamma-Undecalactone. For no reason I have ever been able to understand it is also called Aldehyde C-14 because it is not an aldehyde, it doesn’t even decompose to an aldehyde. The nomenclature craziness continues as a smaller lactone, gamma-Nonalactone, is called Aldehyde C-18 and also called Coconut Lactone. This kind of confusing way of referring to the molecules drives the chemist crazy. Don’t even get me started on Aldehyde C-16 which is neither lactone or aldehyde nor structurally similar to the two above.

Peach Lactone is the key ingredient in one of the best perfumes of all time, Jacques Fath Iris Gris. Dawn Spencer Hurwitz used it as a key component of her reconstruction of this fragrance for her recent Scent of Hope. Peach Lactone forms a gauzy fruity layer carrying smooth creamy components. Peach Lactone is also found as the source of that fruit in Guerlain Mitsouko. In almost every great case I can think of if you smell peach in a perfume this is probably the chemical behind it.

massoia lactone

One of the most amazing uses of lactones has come recently in 2011’s Hermes Hermessence Santal Massoia by perfumer Jean-Claude Ellena. M. Ellena takes Massoia Lactone and uses it to bridge the natural creamy qualities of fig and sandalwood. Massoia Lactone besides the creaminess also has a rich caramel aspect and it is this which creates a dulce de leche accord in the middle of Santal Massoia.

If you smell fruit and cream in your perfume it is lactones which are probably responsible.

Mark Behnke

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