1,1,6-Trimethyl-1,2-dihydronaphthalene (TDN) is an aroma compound present in wine, particularly aged Rieslings. Chemically, it is classified as a 13C-norisoprenoid, as it has thirteen carbon atoms, and is derived from an isoprenoid by the loss of methylene groups.
In wines, TDN is generally considered to contribute to a desirable aroma in low concentrations, but an undesirable aroma in higher concentrations. The aroma is commonly described as a petrol note or by the French term goût de pétrole.
TDN is believed to be a degradation product of ò-carotene and lutein. TDN can also by synthesized in the laboratory from either of the ionones, ñ-ionone or ò-ionone.