Collect. Czech. Chem. Commun.
2007, 72, 1319-1330
https://doi.org/10.1135/cccc20071319
Methyl Steroids. Studies on the Synthesis of 4-Methyl- and 4,4-Dimethyl-25-hydroxycholestan-3-one Derivatives
Iwona Skiera and Zdzisław Paryzek*
Faculty of Chemistry, A. Mickiewicz University, 60-780 Poznań, Poland
Abstract
The synthetic routes to 25-hydroxy derivatives of 4-methylcholest-4-ene and 4,4-dimethylcholest-5-ene from methyl lithocholate and methyl 3β-acetoxy-24-homochol-5-en-25-oate (6) have been investigated. The cholest-5-ene-3β,25-diol (7), readily available from 6, was transformed in a few steps into the title compounds. It was also found that bromination of 24-acetoxy-5β-cholan-3-one (1) and of its enol acetate followed by dehydrobromination is not a regioselective reaction. Formation of mixtures of 2β-bromo-3-oxo and 4β-bromo-3-oxo compounds, which gave mixtures of 24-acetoxychol-4-en-3-one (4) and 24-acetoxy-5β-chol-1-en-3-one (5) of similar polarity was observed. 4-Methyl-25-hydroxycholest-4-en-3-one (14) and 4-methyl-25-hydroxycholesta-1,4-dien-3-one (16) are potential substrates for the preparation of 4-methyl analogs of vitamin D3.
Keywords: 25-Hydroxy steroids; 4-Methyl steroids; Alkylation; Methylation; Bromination; Cholestane.
References: 40 live references.
