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 CDCI 3 , DMSO‐ d 6 , CD 3 OD and D 2 O. 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.