Compounds Related to Juvenile Hormone. II2

Abstract

We recently reported (Braun et al. 1968) 2 convenient synthetic pathways leading to methyl 10,11-epoxy-7-ethyl- 3,11-dimethyl-2,6-tridecadienoate (I) (see Fig. 1), the insect juvenile hormone isolated by Roller et al. (1967) from adult male cecropia moths, Hyalophora cecropia (L.), and later identified by the same group (Dahm et al. 1967). Even though compound I, I-a, when it is prepared by our methods, is presumably a mixture of all 16 possible isomers, it displayed very high juvenile hormone activity when it was assayed with pupae of the yellow mealworm, Tenebrio molitor L., by the method of Bowers and Thompson (1963). Compound I-a was about ⅓ as active as the natural juvenile hormone (Roller et al. 1965) and twice as active as methyl 10,11-epoxy-3,7,11-trimethyl-2,6- dodecadienoate (II) (Bowers et al. 1965), one of the most active synthetic compounds to date. Subsequent preparation of additional quantities of I by reaction scheme B outlined in our earlier publication (Braun et al. 1968) and the more convenient epoxidation procedure using m -chloroperbenzoic acid led to a product (I-b) with activity about ⅓ that of our product (I-a), which was prepared using the epoxidation method of van Tamelen and Sharpless (1967). This loss of activity is not surprising, since peracid epoxidation is known to be much less selective (leading to a mixture of 10,11 and 6,7 epoxides) than the van Tamelen procedure, which yields terminal epoxides almost exclusively.