Petuniasterones, novel ergostane-type steroids of Petunia hybridia Vilm. (Solanaceae) having insect-inhibitory activity. X-Ray molecular structure of the 22,24,25-[(methoxycarbonyl)orthoacetate] of 7α,22,24,25-tetrahydroxy ergosta-1,4-dien-3-one and of 1α-acetoxy-24,25-epoxy-7α-hydroxy-22-(methylthiocarbonyl)acetoxyergost-4-en-3-one

Three new types of ergostanoids with unusual functionalities were isolated from leaves and stems of Petunia hybrids. These include the [(methylthio)carbonyl]orthoacetate of (22R,24R)-7α,22,24,25-tetrahydroxyergosta-1,4-dien-3-one (1) and the respective [(methylthio)carbonyl]acetates, acetates, and free 22-alcohols derived from (22R,24S)-1α-acetoxy-24,25-epoxy-7α,22-dihydroxyergosta-4-en-3-one [(3), (4), and (5)] and (22R,24S)-24,25-epoxy-7α,22-dihydroxyergosta-1,4-dien-3-one [(6), (7), and (8)]. Structures of compounds (2) and (3) were determined by X-ray crystallography. Compound (1) reduced the growth of Heliothis zea larvae to 50% of control values at ca. 40 p.p.m. in artificial diets.