Synthetics
(e)-tiglic acid has no known odor.
Mosciano, Gerard P&F 17, No. 5, 127, (1992): Pungent acidic, with a brown, ripe and fruity nuance
Luebke, William tgsc, (1995): Sweet dry spicy woody caramel
Prodasynth: Warm,leather,animal,spicy
Bedoukian Research: Spicy, cake-like, caramel, woody character
For bready caramel notes in fragrances.