Chemical protection of pheromones containing an internal conjugated diene system from isomerization and oxidation.

Conjugated diene systems are common in natural products, including pheromones. The systems are sensitive to heat, light, and oxygen, among other things. They can be protected by antioxidants and UV absorbers, which slow downcis-trans isomerization and oxidation. Three sex pheromones (one as an analog) containingZ,E, E,Z, andE,E units were studied: (Z,E)-9,11-C14OAc, (E,Z)-7,9-C12OAc, and (E,E)-10,12-C16OAc. The UV absorber 2-hydroxy-4-methoxybenzophenone and the antioxidants BHT and BHA were found to be effective in solution. The protective effect of the UV absorber against photoisomerization on paper carriers was not as good as that in solution. Preliminary studies on the utilization of formulations containing these compounds and (Z,E)-9,11-C14OAc in the mass trapping of Egyptian cotton leafworm male in cotton fields showed the new combinations to be as good as a previously used formulation with UOP 688, a compound which is unpleasant to handle.