Synthesis of deuterium labeled cholesterol and steroids and their use for metabolic studies

Abstract

A simple method is described for the preparation of [6,7,7(-2)H3] sterols and steroids. The synthesis starts with a Δ(5)-sterol or steroid and involves preparation of the 6-oxo-3α,5α-cyclosteroid, base exchange in the presence of deuterium oxide to introduce two deuteriums at the C-7 position and sodium borodeuteride reduction of the 6-oxo group to introduce the third deuterium atom at C-6. Rearrangement of the [6,7,7(-2)H3]6α-hydroxy-3α,5α-cyclosteroid then gives the desired [6,7,7(-2)H3]-Δ(5) sterol or steroid. [6,7,7(-2)H3]Cholesterol, [6,7,7(-2)H3]pregnenolone and [6,7,7(-2)H3]3β-hydroxyandrost-5-en-17-one were synthesized in this fashion and [6,7,7(-2)H3]progesterone was prepared from the [6,7,7(-2)H3]pregnenolone. Three examples of the use of these deuchromatography-mass spectrometry. The chrysophyte alga,Ochromonas malhamensis, was shown to be capable of introducing an extra methyl or ethyl group at C-24 of the side chain of [6,7,7(-2)H3]cholesterol to yield brassicasterol and poriferasterol, respectively. The ovary of the echinoderm,Asterias rubens, was demonstrated to metabolize [6,7,7(-2)H3]progesterone to yield mainly the 5α-isomers of pregnane-3,20-dione and 3β-hydroxypregnan-20-one. However, the 5β-isomers of these compounds were also detected as minor products for the first time as progesterone metabolites in this animal. Isolated oocytes of the frog,Xenopus laevis, produced a number of metabolites of [6,7,7(-2)H3]progesterone. In this report, two of them were shown to be 17α-hydroxy-pregn-4-en-3,20-dione and 20α-hydroxypregn-4-en-3-one.

Cholesterol Orientation and Dynamics in Dimyristoylphosphatidylcholine Bilayers: A Solid State Deuterium NMR Analysis

“…The ⌬ 5 -[6,7,7-2 H 3 ]cholesten-3␤-ol was prepared according to the method of Goad et al (1982), starting from 3␣,5␣-cyclocholestan-6-one whose synthesis is detailed in the publication of Palmer et al (1978). The ⌬ 5 -[6,7,7-2 H 3 ]cholesten-3-ol was characterized by electron impact mass spectrometry m/z as follows: 303, 275, 246; and by 1 H NMR(CDCl 3 ) as follows: ␦ 0.72 (s, H-18), 0.89 (d, H-26 and H-27), 0.92 (d, H-21), 1.2 (s, H-19), 3.7 (m, H-3␣).…”

The biosynthesis of triterpenoids and steroids

“…The highly stereospecific labelling of poriferasteroi in this experiment suggests that a 24-ethylidenesteroid, of defined configuration, is the natural precursor.366 It has been confirmed that 0. malhamensis is capable of introducing a methyl or ethyl group at C-24 of cholesterol to furnish brassicasterol (1 71) and poriferasterol, respectively. 367 The biosynthesis of the fascinating steroid dinosterol (1 72a) in the marine dinoflagellate Crypthecodinium cohnii has been Feeding experiments with [Me-'H,]rnethionine furnished deuteriated dinosterol that was shown by mass spectrometry to contain the 'H2-, ?H3-, and 'H,-labelled species (1 72b-d).…”