Synthesis of deuterium-labelled 17α-hydroxypregnenolone for use as internal standard in stable isotope dilution/mass spectrometry

Abstract

Using a 4‐step scheme, we have synthesized deuterium‐labelled 17α‐hydroxypregnenolone for use as internal standard for an isotope dilution/mass spectrometry plasma assay. 17α‐Hydroxyprogesterone served as starting material. Its 17α‐hydroxygroup was protected by tetrahydropyranylation. Introduction of deuterium by base‐catalyzed enolization and protection of the 3‐hydroxygroup by acetate formation yielded [2,2,4,21,21,21‐2H6]3β,17α‐dihydroxypregna‐3,5‐diene‐20‐one 3‐acetate 17‐tetrahydro‐pyranyl ether. After reductive deuteration of the 3‐ene and removal of the protecting groups [2,2,4,4,21,21,21‐2H7] 17α‐hydroxypregnenolone was obtained. © 1998 John Wiley & Sons, Ltd.

Synthesis of [3α‐3H] 17α‐Hydroxy pregnenolone and [3α‐3H] Pregnenolone

“…All products were fully characterized by detailed analytical data. With the help of T-NMR and Chiral PAK AD HPLC, the existence of (7) and its transformation to (6) that had not been reported by previous publications were revealed. The [3β-3 H] isomer of 17α-hydroxy pregnenolone, which was not mentioned in previous publications was discovered, then isolated giving a pure product (1).…”

“…Although the synthesis was unsuccessful, the results we obtained provided interesting information on the conversion from (7) to (6). The analytical methods we developed were useful later for separation and characterization of the desired products.…”

“…We initially attempted to synthesize [3α-3 H] 17α-hydroxy pregnenolone (1) by utilizing 3,5-pregnadien-3,17-diol-20-one-3-methyl ether (3), a commercially available precursor via reduction of the 3-keto group (Scheme 1). Instead of the desired [3-3 H] product (1), a mixture of [20α-3 H] 4-pregnen-17α,20betadiol-3-one (6) and [20α-3 H] 5-pregnen-17α,20 beta-diol-3-one (7) were isolated (Scheme 1). After RP-HPLC purification, the (6)/(7) mixture showed a single peak with 99.7% RCP by RP-HPLC.…”

“…Deuterium-labeled 17αhydroxypregnenolone, such as [21-2 H3] and [2,2,4,4,21,21,21-2 H7] 17α-hydroxypregnenolone, was prepared, respectively, by Muhammad Akhtar 5 and C. Solleder. 6,7 No publication was found reporting the synthesis of [3α-3 H] 17α-hydroxy pregnenolone. However, George E. Joannou 8 reported a multiple step procedure to prepare unlabeled 17α-hydroxy pregnenolone.…”

“…In addition, Weinman reported the synthesis of [16‐ 3 H] 17 α ‐hydroxypregnenolone. Deuterium‐labeled 17 α ‐hydroxypregnenolone, such as [21‐ 2 H3] and [2,2,4,4,21,21,21‐ 2 H7]17 α ‐hydroxypregnenolone, was prepared, respectively, by Muhammad Akhtar and C. Solleder . No publication was found reporting the synthesis of [3 α ‐ 3 H] 17 α ‐hydroxy pregnenolone.…”