The derivatives are concrete and absolute. The concrete is prepared
in approximately 1.5 to 2.0% yields by solvent extraction (ben zene, petroleum ether) of the freshly cut flowering herb. It is a
dark-green, viscous mass. An absolute is obtained in approxi mately 45% yields by distillation of the concrete with diethylene
glycol.
2-Isopropyl-5-methyl-2-hexenal has a fruity, blueberry odor.
By aldol condensation of isovaleraldehyde
Aroma characteristics at 1.0%: woody, musty, nutshell-like, slightly floral and cooling with a honey and
cocoa creamy nuance.
Taste characteristics at 10 ppm: woody, nutshell, cocoa hulls, thiazole-like creamy nuance and a fresh, fruity
peachlike nuance.
2-Isopropyl-5-methyl-2-hexenal is a volatile aroma constituent of malted barley and roasted coffee beans. It can be formed via Maillard reaction between leucine and 3-methylbutanal.
