CONFORMATIONAL BEHAVIOR OF INSECT PHEROMONES AND ANALOGS .2.

The conformational potential energy surface paths of the sex pheromone, Ipsenol, to the Bark Beetle, Ips typographus, and of a series of analogues have been elucidated using the program DAISY. The following structures were calculated: 2-methyl-6-methylene-7-octen-4-ol (Ipsenol, (II)), 2-methyl-6-methylene-2,7-octadiene-4-ol acetate (III), 2-methyl-6-methylene-3,7-octadien-2-ol (IV), 2-methyl-6-methylene-1,7-octadien-3-ol (V), 5-(3-furanyl)-2-methyl-1-penten-3-ol (VI) and 1-(3-furanyl)-4-methyl-3-penten-2-ol (VII). As a measure of the conformational flexibility of the molecules the flexibility coefficients, f, were determined. The f values for the molecules were determined to be: II, 0.145; III, 0.144; IV, 1.240; V, 0.133; VI, 0.825; and VII, 0.451. The molecular mechanics method was used for energy calculations in conjunction with DAISY. Low-energy conformations (conformational channels) together with energy barriers for conformational changes are presented.