Alan B. Turner

A Review on Synthetic and Natural Steroid Dimers: 1997-2006

Since the publication of the review by Li and Dias in 1997, which covered almost all steroid dimers known to us until the early part of 1997, there have been significant amounts of work carried out on steroid dimers, and another review on this topic has long been overdue. Thus, this review presents a comprehensive review of literature published over the last decade on various aspects of steroid dimers, including synthesis and applications. Steroid dimers that were published before 1997 but were not covered within the previous review have also been included.

Synthesis, X-ray structure and molecular mechanics studies of the boar taint steroid (5α-androst-16-en-3-one)

Abstract 5α-Androst-16-en-3-one has been prepared from 5α-androstan-3β-ol-17-one in an overall yield of 34% by the vinyl iodide route. Accurate molecular dimensions have been determined by X-ray crystal structure analysis and by molecular mechanics calculations. There is significant twisting of the angular methyl groups in the molecule.

Synthesis of ester-linked lithocholic acid dimers.

Four lithocholic acid dimers were synthesised via esterification. The ester-linked dimer, 3-oxo-5beta-cholan-24-oic acid (cholan-24-oic acid methyl ester)-3-yl ester, (3alpha,5beta), was obtained by condensation of methyl lithocholate with 3-oxo-5beta-cholan-24-oic acid. Borohydride reduction of this ester-linked dimer gave 3alpha-hydroxy-5beta-cholan-24-oic acid (cholan-24-oic acid methyl ester)-3-yl ester, (3alpha,5beta), which was acetylated to 3alpha-acetoxy-5beta-cholan-24-oic acid (cholan-24-oic acid methyl ester)-3-yl ester, (3alpha,5beta). Reaction of methyl lithocholate with oxalyl chloride yielded the oxalate dimer, bis(5beta-cholan-24-oic acid methyl ester)-3alpha-yl oxalate.

Convenient synthesis of new pregnenolone oximinyl oxalate dimers

Three new symmetrical pregnenolone oxyminyl oxalate dimers (8–10) were synthesized from the corresponding pregnenolone oximes (3, 5, and 7) at room temperature. All dimers were characterised by spectroscopic means, notably HRFABMS and comprehensive NMR spectroscopic data analyses.

Facile synthesis of new oxalate dimers of naturally occurring 3-hydroxysteroids

Several symmetrical steroidal oxalate dimers were synthesised from naturally occurring 3-hydroxysteroids, namely, estrone (1), DHEA (3), pregnenolone (5), cholesterol (7), 5D-cholestane (9), and stigmasterol (11), using oxalyl chloride. Full spectroscopic data for all the new compounds are presented.

Synthesis of dinorcholane and 5ß-cholane derivatives

The convenient synthesis of seven dinorcholane and 5β-cholane derivatives, 3β-acetoxy-23,24-dinorchol-5-en-22-oyl methoxy anhydride (2), 3β-acetoxy-23,24-dinorchol-5-en-22-oyl chloride (3), 3β-acetoxy-23,24-dinorchol-5-en-22-ol (4), 3α-acetoxy-5β-cholan-24-oic acid (6), 3α-acetoxy-5β-cholan-24-oic acid ethyl ester (7), 3-oxo-5β-cholan-24-oic acid (8) and 3-oxo-5β-cholan-24-oic acid ethyl ester (9) have been described. Full spectroscopic data for these compounds are presented.

Synthesis and X-ray crystal structure of 5β-cholan-24-yl chloride

5β-cholan-24-yl chloride (5) was prepared from lithocholic acid (1) in four steps, and following spectral investigations its crystal and molecular structure was determined by X-ray crystallography.

Synthesis and preliminary odour evaluation of the 14β-epimer of the boar taint steroid☆

Abstract 5α,14β-Androst-16-en-3-one (14- epi -androstenone) has been prepared from 3β-hydroxy-5α, 14β-androstant-17-one, by the vinyl iodide route in an overall yield of 35%. Its odour is similar to, but significantly less intense than, that of the naturally occurring 14α-epimer.

Synthesis of New Estrone Derivatives Using Excess Oxalyl Chloride

The synthesis and structure elucidation of three new estrone derivatives chloro-oxo-acetic acid (estra-1,3,5(10)-trien-17-on-3-yl methyl) ester (2), oxalic acid mono (estra-1,3,5(10)-trien-17-on-3-yl methyl) ester (3), and ethyl (3-methoxyestra-1,3,5(10)-trien)-17β-yl oxalate (5) have been described.

Synthesis and preliminary odour evaluation of 5α-androst-16-en-7-one: a new androstenone analogue

Abstract 5α-Androst-16-en-3-one has been prepared from 5α-androstane-7,17-dione in a five-step sequence, via selective ketalisation at C-7 with bis-trimethylsilyloxyethane and trimethylsilyl triflate as the key step, followed by introduction of the Δ 16 bond by reaction of the 17-hydrazone with iodine to give the vinyl iodide, and deiodination with sodium in ethanol, with acid-catalysed deprotection of the 7-oxo group as the final step. The compound has a mild sandalwood odour.