Material guide: Helvetolide, an -olide that is not a lactone, with two database fields contradicting each other

In short: a textbook case of a trade name misleading you, and the way it misleads is specific. The suffix says lactone; the formula says otherwise.

Fields

Field	Value
CAS	141773-73-1
EINECS	415-490-5
First synonym	helvetolide (Firmenich)
Formula	C17H32O3, MW 284.440
Database category	fragrance agents
Assay	95.00 to 100.00
Boiling point	346-347 C @ 760 mmHg (est)
Flash point	122.90 C (est)
logP	4.50 (est)
Water solubility	0.2975 mg/L @ 25 C (est)
Odour type	musk
Odour	musk; ambrette; fruity; pear; woody; floral
Strength	medium (rank 2)
Substantivity	> 336 hours (neat)
Dosage guidance	fine fragrances 0.5-5%; shampoo 0.5-2%; shower gel 0.5-2%; softener 0.5-2%; APC 0.5-2%; soap traces-0.5%; candle traces-0.5%
Natural/synthetic	natural
Occurrence	not found in nature
Suppliers	14
Toxicity	oral, dermal and inhalation all "not determined"

The suffix lies

The -olide suffix generally indicates a cyclic ester, a lactone. This material's formula is C17H32O3.

Three oxygens.

An ester needs two. Three means it can be an ester but not a plain cyclic one, and the name the database gives it says so directly: musk propanoate. That is an open-chain propanoate ester.

(The -olide suffix has hit rates of 44% and 8% in the two directions, measured in What are the -olides. This material is the standard case of a suffix not matching the chemistry.)

Set against its neighbours:

	Formula	Oxygens	Cyclic ester
Exaltolide	C15H28O2	2	yes (the name says lactone)
isoambrettolide	C16H28O2	2	yes
Helvetolide	C17H32O3	3	no (open-chain ester)
Galaxolide	C18H26O	1	cannot be an ester

Two fields contradict each other

The natural/synthetic field reads natural.

The occurrence field reads not found in nature.

This is a synthetic musk developed by Firmenich in the 1990s, so "not found in nature" is right and the "natural" field is wrong.

(Not an isolated incident. 306 records in the library say "not found" in one field and are tagged natural in the other, as computed in The synthetic versus natural argument my database cannot settle. That field cannot be used to filter on.)

The positioning is unusually precise

The odour description field carries one of the most precise product positioning statements I have seen:

"A sophisticated, modern musky note with a fruity pear aspect. Olfactively, between Ambrettolide and Ethylene Brassylate."

That is a coordinate rather than an adjective. I have written up both ends:

	Suppliers	Substantivity	Strength
isoambrettolide	43	248 hours	medium (rank 2)
Helvetolide	14	> 336 hours	medium (rank 2)
ethylene brassylate	52	400 hours	—

The substantivity lands in the middle too. 248 → 336 → 400.

(That > is a lower bound rather than a value, so 336 only supports "at least". What the sign means is in the fixation article.)

The dosage guidance is real numbers

The solubility field carries an application guide, and it gives ranges rather than adjectives:

fine fragrances 0.5-5%; shampoo 0.5-2%; shower gel 0.5-2%; softener 0.5-2%; APC 0.5-2%; soap traces-0.5%; candle traces-0.5%

The fine fragrance ceiling is 5%, higher than most musks. Soap and candle read "traces to 0.5%", an order of magnitude apart.

The same field adds that this musk performs particularly well in liquid applications. That does not conflict with a water solubility of 0.2975 mg/L: liquid applications means stability in aqueous formulations like shampoo and shower gel, not that it dissolves in water.

The toxicity fields are empty

Oral, dermal and inhalation all read Not determined.

The regulatory field is empty too: no FEMA, no JECFA, no CoE, no FLAVIS number.

That does not mean there is a problem; it means this is a fragrance-only molecule that has not been through the food flavour registration process. (Materials with FEMA numbers are usually ones also used as flavours.)

In practice: you cannot look up its safety data in this database and will need the supplier's SDS.

How it differs from Habanolide

Somebody on the forum wanted to combine these two into a clean white musk. Side by side:

	Helvetolide	Habanolide
Database name	musk propanoate	(E)-12-musk decenone
CAS	141773-73-1	111879-80-2
Formula	C17H32O3 (3 oxygens)	C15H26O2 (2 oxygens)
Structure	open-chain ester	macrocyclic lactone
Suppliers	14	14
Odour terms unique to it	pear, ambrette	laundered cloth, metallic

One is an open-chain ester and the other a macrocyclic lactone. And at the receptor level, linear musks and macrocyclic lactones both go through OR5A2, so for any one person their detectability moves together.

(Habanolide's "laundered cloth" descriptor was the key to What is the material that smells fuzzy, static-y, warm.)

What this doesn't establish

• I have not smelled it. This is database fields only.
• "Three oxygens so not a plain cyclic ester" only refutes. Confirming the structure needs a diagram, which I did not check.
• "Developed by Firmenich in the 1990s" is inferred from the head_synonym and EINECS number; the database gives no development date.
• The > 336 hours is a lower bound. The real figure may be much higher, and it was measured neat, so it is not comparable with records measured at 10% dilution.
• The dosage guidance is supplier text, not an independent determination.
• "Between Ambrettolide and Ethylene Brassylate" is the manufacturer's positioning. I checked that the substantivity figures agree in direction, but that is one dimension.
• The empty toxicity fields are this record's state, not a claim that the supplier has no data.
• I did not run corpus statistics.