Synthesis of Deuterium-labelled Estriol, 16α-Hydroxyestrone and Estriol 16-Glucuronide via 2, 4, 16α-Tribromoestrone as Internal Standards for Mass Fragmentography

Synthesis of 1, 3, 5 (10)-estratriene-3, 16α, 17β-triol-d6 and -d7 (4), 3, 16α-dihydroxy-1, 3, 5 (10)-estratrien-17-one-d5 (5) and sodium 3, 17β-dihydroxy-1, 3, 5 (10)-estratrien-16α-yl-β-D-glucopyranosuronate-d6 (8) is described. Treatment of 2, 4, 16α-tribromo-3-hydroxy-1, 3, 5 (10)-estratrien-17-one (1) with sodium hydroxide-OD in deuterium oxide-pyridine under controlled conditions gave the [16β-2H] 16α-hydroxy-17-one (2). The ketol 2 was converted into the triol-d6 (4) via sodium borodeuteride reduction in the presence of palladium chloride. Similar treatment of the 17-ethyleneacetal of 2 followed by acid hydrolysis gave compound 5-d5. Reaction of 2 with methyl 1-bromo-1-deoxy-2, 3, 4-tri-O-acetyl-α-D-glucopyranosuronate using silver carbonate as a catalyst yielded the 16-monoglucuronide acetate methyl ester (6). The reductive removal of the bromines of 6 and subsequent alkaline hydrolysis gave the glucuronide-d6 (8). Mass spectrometric analysis showed compounds 4, 5, and 8 to have good isotopic purity.