The proton magnetic resonance spectra of d-aldosterone and its acetylated derivatives

PMR spectra of d-aldosterone, its acetylated derivatives and related compounds were studied using 60 and 100 MHz spectrometers at various temperatures, in CDCI₃, DMSO-d₆, CD₃OD and D₂O. The aldehyde form ( 1 ) was not found. The solutions of d-aldosterone and aldosterone-21 acetate contain a mixture of the cyclic forms with one (11–18) hemi-ketal bridge ( 2 ) and two (11–18, 18–20) hemi-ketal bridges ( 3 ). Preliminary results concerning modifications of the relative concentration of 2 and 3 obtained by varying solvents and temperature are given. Aldosterone-diacetate exists in only one form, most likely form 2 . There is restricted rotation of the group at C-21 in d-aldosterone and in form 3 of aldosterone 21-acetate. One molecule of water is probably bound to d-aldosterone.