J. B. Stothers

Synthesis of the allylic gonadal steroids, 3α-hydroxy-4-pregnen-20-one and 3α-hydroxy-4-androsten-17-one, and of 3α-hydroxy-5α-pregnan-20-one

Abstract A method for the convenient synthesis of the recently isolated allylic gonadal steroids, 3 α -hydroxy-4-pregnen-20-one (3 α -dihydroprogesterone; 3 α -DHP) and 3 α -hydroxy-4-androsten-17-one (3 α -HA), was developed using 4-pregnene-3,20-dione (progesterone) and 4-androstene-3,17-dione as substrates and potassium trisiamylborohydride (KS-Selectride) as reducing agent. Similar reactions were also used for the reduction of 5 α -pregnane-3,20-dione to 3 α -hydroxy-5 α -pregnan-20-one (3 α -HP). The yields were about 15%, 50%, and >90% for 3 α -DHP, 3 α -HA and 3 α -HP, respectively. Structures of the products, including the 3 β -isomers and the 17 α -epimer, formed in these reactions were determined by NMR and mass spectroscopic methods.

The Structures of some Stress Metabolites from Solanummelongena

The structures of the acyclic sesquiterpenes 1–5 and the bicyclic sesquiterpenes 6 and 7, all isolated from eggplant fruit inoculated with fungi, were elucidated with the aid of 1H and 13C n.m.r. studies. Trienone 1 was found to be identical to 9-oxonerolidol from camphor leaf oil while 2 and 3 are isomeric alcohols derived from 1. Compounds 4 and 5 are probably artifacts. The hydroxyaldehyde 6 is identical with the potato phytoalexin lubimin, originally represented by a structure shown here to be incorrect. Enone 7 is a novel eudesmane. The stereochemistries of these compounds are discussed.

Metabolites of part V. Biosynthesis of altersolanol A and incorporation of altersolanol A-13Cx into altersolanol B and macrosporin ☆

Abstract The biosynthesis of the tetrahydroanthraquinone, altersolanol A ( 1 ), by Alternaria solani has been established by the incorporation of [1,2-13C2]-acetate. A blocked culture of A. solani was utilized to reveal that 1 is metabolized to altersolanol B and macrosporin.

Synthesis and characteristics of allylic 4-pregnene-3,20-diols found in gonadal and breast tissues

Recently several allylic steroids have been found in gonadal and breast tissues. In order to establish their presence and identity in tissues and determine the possible biological properties, a method for the synthesis of 4-pregnene-3 alpha,20 alpha-diol, 4-pregnene-3 alpha, 20 beta-diol, 4-pregnene-3 beta,20 alpha-diol, and 4-pregnene-3 beta,20 beta-diol was developed using 4-pregnene-3,20-dione (progesterone) as substrate and freshly-prepared aluminum isopropoxide in isopropyl alcohol as reducing agent. The yields were about 19%, 30%, 13%, and 38% for the 3 alpha,20 alpha-, 3 alpha,20 beta-, 3 beta,20 alpha-, and 3 beta,20 beta-diols, respectively. The structures and stereochemistry of these diols were established using proton and carbon NMR spectroscopy and infrared and mass spectrometry.