A solution of 70% perchloric acid (60 ml) in water (280 ml) was added to a
stirred solution of 5α-androst-2-en-17-one (200.0 g) in ether (1.15 l) at 15°C
followed by portionwise addition of N-bromacetamide (112.0 g) over 10 min.
After stirring for 1 h the precipitated white crystalline solid was filtered off,
washed neutral with ether and water and crystallised to give 2β-hydroxy-3α-
bromo-5α-androstan-17-one (172.0 g). The ether layer of the filtrate was
washed neutral, dried (Na2SO4) and concentrated to give a second crop (28.0
g). The two crops (200.0 g) were suspended in methanol (1 L), 10 N aqueous
potassium hydroxide solution (100 ml) added and the mixture slowly distilled
over 45 min. Addition of water precipitated the product as a white solid which was filtered off, washed with water, dried and 88.0 g of 2β,3β-epoxy-5α-
androstan-17-one were obtained (crystallisation from ether:light petrol).
A solution of the 2β,3β-epoxy-5α-androstan-17-one (30.0 g) in ethanol (130
ml), water (15 ml) and liquid ammonia was heated in an autoclave at 150°C
for 6 h and the resultant crystalline suspension evaporated to dryness. Water
(35 ml) and acetic acid (36 ml) were added and the solution kept at 90°C for
1 h, cooled and excess water added. The precipitated material was filtered off
and the filtrate made alkaline with aqueous 10 N potassium hydroxide solution
to precipitate a white solid which was filtered off, washed neutral with water,
dissolved in methylene chloride, the solution dried (Na2SO4) concentrated and
ether added to give 2β-hydroxy-3α-amino-5α-androstan-17-one (14.3 g),
melting point l92°-195°C.
In practice it is usually used as hydrochloride.
