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The trimethylundecane unsaturated aldehydes are mostly floral aliphatic aldehydes, having rather related olfactory properties and similarity in the molecular structure, suggesting a possible SOR (structure-odor-relationship).
2,6,10-Trimethyl-9-undecenal is a fresh, aldehydic, marine, powerful, floral ingredient. 2,6,10-Trimethyl- 9-undecenal blends extremely well with floral notes such as lily of the valley and cyclamen, as well as with fruity and woody compositions. It can also be seen as having a typical fresh linen odor which makes it very useful for detergent perfumes. 2,6,10-Trimethyl-9-undecenal has a natural, ozonic aspect and due to its high j value it must be used carefully.
2-Methyl-4-(2,6,6-trimethyl-2(1)-cyclohexen-1-yl) butanal (CAS# 65405-84-7, cetonal) is another aliphatic unsaturated aldehyde; having an orris, woody, powerful odor, it is an elegant ingredient used in woody, orris accords as well as with leather, tobacco and animal notes where it acts as an excellent blending agent and adds to the harmony of a fragrance.