Synthesis of the 1.BETA.-hydroxylated bile acids, unusual bile acids in human biological fluids.
作者:MASAHIKO TOHMA、REIJIRO MAHARA、HIROMI TAKESHITA、TAKAO KUROSAWA、SHIGEO IKEGAWA
DOI:10.1248/cpb.34.2890
日期:——
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.
1β-羟基胆酸(10a)、脱氧胆酸(10b)、鹅去氧胆酸(10c)和胆酸(10d)是从相应的胆酸甲酯(1a-d)作为起始原料合成的。Δ1-不饱和酮(6a、e-g)是通过用乙酸铬还原脱除其2,4-二溴化物(3a、e-g)的溴,并用碳酸锂-溴化锂脱氢,然后用碱性过氧化氢氧化,得到1β-2β-环氧酮(7a、e-g)。环氧物(7a、e-g)的还原裂解和随后的硼氢化钠还原反应得到1β,3α-二羟基化合物(9a、e-g),后者被水解为1β-羟基胆酸(10a-d)。通过气相色谱-质谱分析,在健康男性和肾脏疾病患者的尿液中鉴定出1β,3α,12α-三羟基-5β-胆烷-24-酸(10b)。在人类胎粪中检测到新的1β,3α,7α-三羟基-(10c)和1β,3α,7α,12α-