Aliphatic and aromatic trifluoromethyl ketones have been evaluated in
the laboratory and in the field as inhibitors of the pheromone respons
e of the processionary moth Thaumetopoea pityocampa males. Among them,
two compounds, (Z)-1,1,1-trifluoro-15-octadecen-13-yn-2-one and (Z)-1
,1,1-trifluoro-16-nonadecen-14-yn-2-one, are closely related analogs o
f the natural pheromone (Z)-13-hexadecen-11-ynyl acetate. In the labor
atory experiments, carried out by pre-exposure of males to vapors of t
he chemicals, or-naphthyl trifluoromethyl ketone, beta-naphthyl triflu
oromethyl ketone, 1,1,1-trifluorotetradecan-2-one and (Z)-16-nonadecen
-14-yn-2-one displayed notable blockage of the pheromone detection on
EAG. The activity of 1,1,1-trifluorotetradecan-2-one is postulated to
be due to the inhibition of the pheromone-degrading esterase. In gener
al, the compounds have shown low specificity for the substrate and exh
ibited only a modest or null EAG intrinsic activity. In the field, ben
zyl trifluoromethyl ketone, trifluoroacetophenone, (Z)-1,1,1-trifluoro
-15-ociadecen-13-yn-2-one, (Z)-1,1,1-trifluoro-16-nonadecen-14-yn-2-on
e and beta-naphthyl trifluoroacetate showed a remarkable disruptant ef
fect when mixed with the pheromone in 1:0.1, 1:1 and 1:10 ratio. (Z)-1
6-Nonadecen-14-yn-2-one has been found to be a modest agonist of the n
atural pheromone, exhibiting an attractant activity threefold lower th
an the parent molecule.