I. The structures of the Phytoecdysones The structure of the following phytoecdysones are discussed. As all ecdysones are polyols, the dibenzoate chirality rule or its extention provide a very convenient method for configurational and conformational studies of such compounds. a) Ajugasterone C (2). The dibenzoate chirality rule, as applied to (6) and the model compound (8), indicates that it can be extended to 1,2,6-triols and establishes the 11-OH configuration to be a. b) Ajugasterone D. Preliminary data show this to be structurally isomeric to ajugasterone B (9) at C_<24>-C_<29>. c) Ponasterone C (15). The previous structure, 24-hydroxy-(10) has been revised to (15). Optical and nmr (NOE) data of other 5-hydroxy-7-en -6-one have been measured in conjunction with structural studies. Ponasterone B ((10) and (14)), the structure of which has been reconfirmed, is thus the only ecdysone having 2α and 3α hydroxy groups. d) Stachysterone A (24), B (25), C (28) and D (29). Stachysterone A is the first ecdysone to have a rearranged skeleton. e) Ajugalactone (30). The activity of this compound possessing a 14β-OH appears to be quite unusual. II. Stereochemistry of the side-chain The configuration at C-22 in the majority of ecdysones has been established as being R. The C-20 configuration will be discussed. III. Metabolism of choesterol and ecdysones in B. mori Bioorganic studies (injection or feeding) employing fifth instar larvae of Bombyx mori, 23,24-^3H-a-ecdysone and 4-^<14>C-cholesterol enables one to propose Scheme 1. It is to be noted, besides other results, that α- and β-ecdysones are biosynthesized from cholesterol in the posterior half of the insect which does not contain the prothoracic gland.
