18,19-Dihydroxydeoxycorticosterone, a new metabolite produced from 18-hydroxydeoxycorticosterone by cytochrome P-450(11) beta. Chemical synthesis and structural analysis by 1H NMR

A new metabolite was produced from 18-hydroxydeoxycorticosterone by the cytochrome P-450(11) beta linked hydroxylase system purified from bovine adrenocortical mitochondria. It was identified as 18,19-dihydroxydeoxycorticosterone by chemical synthesis on the basis of high-performance liquid chromatography, gas chromatography-mass spectrometry, and proton nuclear magnetic resonance (1H NMR) spectroscopy, and detailed structural analysis of it was performed by 1H NMR spectroscopy. The methylene protons at the C-19 position of the steroid were nonequivalent and coupled with each other, having a coupling constant of 10.6 Hz. These protons had different coupling constants, 6.7 and 3.4 Hz, for the hydroxy proton at the C-19 position. Due to these couplings, the signals of the methylene protons were observed around 3.9 ppm as two double doublets. The methylene protons at the C-21 position were also nonequivalent, having a coupling constant of 11.1 Hz. Coupling constants between these methylene protons and the hydroxy proton at the C-21 position were 8.2 and 4.2 Hz, respectively. These results indicate that both hydroxymethyl groups at the C-19 and C-21 positions do not freely rotate in chloroform solution. The signals of hydroxy protons at the C-19 and C-21 positions were found at 1.25 and 1.87 ppm, respectively, by means of decoupling of the corresponding methylene protons. The hydroxy proton at the C-18 position was found to scarcely couple with any proton. This fact suggests that this hydroxy group is linked to the C-20 position, making a hemiketal bridge between the C-18 and the C-20.