Juvabione and its analogues. II. Isolation, identification, and occurrence of juvabiol and its epimer isojuvabiol from the whole wood of Abies balsamea

Epimeric mixtures of juvabiol (3a) and isojuvabiol (4a) have been detected in six North American Abies balsamea (L.) Mill. trees and isolated from the whole-wood extract of three. These juvabione related alcohols are insect juvenile hormone analogues with selective action typical of juvabione (1) and Δ4′-dehydrojuvabione (2). The widespread occurrence of these alcohols indicates that the original 'paper factor' was not due to 1 alone, nor was it due to a mixture of 1 and 2. In addition a fifth IJHA with selective action, Δ3′-dehydrojuvabi-5′-ol (5), was detected in the hot ethanol extract of four trees and isolated from one tree. It is shown that 5 is an allylic rearrangement product of the Δ4′-dehydrojuvabiols 6a and 7a. Mixtures of campesterol and sitosterol are the major crystalline components present in all the petroleum ether soluble extracts.