Trans,cis-2,6-Nonadienal
trans,''cis''-2,6-Nonadienal is an organic compound that is classified as a doubly unsaturated derivative of nonanal. The molecule consists of a α,β-unsaturated aldehyde with an isolated alkene group. The compound has attracted attention as the essence of cucumbers, but it is also found in bread crust and freshly cut watermelon.