18-substituted steroids--9[1]. Studies on the stability of aldosterone in dilute alkali.

In the presence of dilute alkali at room temperature aldosterone undergoes rearrangement to form an isomeric compound identified as 11 beta, 18;18,21-diepoxy-20,21-dihydroxypregn-4-en-3-one. The presence of dissolved oxygen causes simultaneous degradation to form 11 beta, 18-epoxy-18-hydroxy-3-oxo-17(beta H)-androst-4-ene-17 alpha-carboxylic acid. Under similar alkaline conditions at reflux temperature in aqueous methanol aldosterone undergoes rearrangement to form (20S)-20,21-dihydroxy-3-oxo-pregn-4-eno-18,11 beta-lactone accompanied by an intramolecular aldol type condensation to form 11 beta, 21-dihydroxy-18,21-cyclopregna-4,18(21)-diene-3,20-dione. Identical products were formed from 17-isoaldosterone. The mechanisms of these reactions are discussed.