Synthesis of the 1.BETA.-hydroxylated bile acids, unusual bile acids in human biological fluids.

Abstract

1β-Hydoxylated lithocholic (10a), deoxycholic (10b), chenodeoxycholic (10c) and cholic (10d) acids were synthesized from the corresponding bile acid methyl esters (1a-d) as starting materials. The Δ1-unsaturated ketones (6a, e-g) were prepard from the 3-oxo bile acid esters (2a-d) via reductive debromination of their 2, 4-dibromides (3a, e-g) with chromous acetate and dehydrobromination with lithium carbonate-lithium bromide, and oxidized with alkaline hydrogen peroxide to give the 1β-2β-epoxyketones (7a, e-g). Reductive cleavage of the epoxides (7a, e-g) and subsequent reduction with sodium borohydride afforded the 1β, 3α-dihydroxy compounds (9a, e-g), which were hydrolyzed to the 1β-hydroxylated bile acids (10a-d). 1β, 3α, 12α-Trihydroxy-5β-cholan-24-oic acid (10b) was identified in the urine of healthy men and patients with kidney disease by gas chrmatography-mass spectrometric analysis. Novel 1β, 3α, 7α-trihydroxy-(10c) and 1β, 3α, -7α, 12α-tetrahydroxy-5β-cholan-24-oic acids (10d) were detected in human meconium.