Isobutyl thiazole

Say iteye-soh-BYOO-til THYE-uh-zohl

Green tomato leaf and vine; pungent, earthy and slightly sulfurous.

What it is: A molecule made in a lab.
Where it comes from: synthetic, natural in tomato leaves
When you smell it: Top notes: the first minutes.
What perfumers do with it: Recreates tomato-leaf and garden-green effects; around 0.1% in a perfume concentrate.
Also called: 2-Isobutylthiazole; tomato thiazole

Not on the label of any of the 232 perfumes read so far.

Sources