30122-70-4Relevant academic research and scientific papers
Reaction of androst-5-en-17-one with hypobromous acid and its use for synthesis of 19-oxygenated 5-ene and 4-en-6-one steroids
Numazawa, Mitsuteru,Yamada, Keiko
, p. 62 - 69 (1998)
Reaction of androst-5-en-17-one (1) with hypobromous acid using a short reaction time (30 min) along with a careful isolation procedure gave, for the first time, the addition product, 5α-bromo-6β-hydroxyandrostan-17-one (3), in 43% yield. This bromohydrin was much more reactive than 5α-bromo-3β- acetoxy-6β-hydroxyandrostan-17-one (4) towards KHCO3 and HClO4. The high reactivity of compound 3 was found to be a principal reason for the difficulty in isolating this compound by the addition reaction so far. 19- Hydroxyandrost-5-en-17-one (16) and androst-5-ene-17,19-dione (18), as well as 19-hydroxyandrost-4-ene-6,17-dione (28) and androst-4-ene-6,17,19-trione (29), were synthesized through hypoiodite reaction of the bromohydrin 3 as a key reaction.
The Westphalen rearrangement of 5α, 6α-epoxy-3β- methanesulfonyloxyandrostan-17-one
Knights, Steve G.,Hanson, James R.
, p. 830 - 831 (2007/10/03)
5α,6α-Epoxy-3β-methanesulfonyloxyandrostan-17-one undergoes a Westphalen backbone rearrangement rather than an aromatisation in acetic acid: acetic anhydride containing sulfuric acid catalyst, suggesting that under these conditions the formation of a 5α-sulfate from the epoxide and its ionisation takes precedence over the elimination of the 3β-methanesulfonate.
Competing pathway involved in allylic acetoxylation of androst-5-en-17-one, and oxidation of allylic alcohols with chromium oxides
Numazawa, Mitsuteru,Tachibana, Mii,Kamiza, Miyako
, p. 569 - 575 (2007/10/03)
Allylic acetoxylation of androst-5-en-17-one (1) with bromine and silver acetate gave 6α- and 6β-acetoxyandrost-4-en-17-ones and 5α-bromo-6β-acetoxy steroid 8 (4percent) along with the expected product 4β-acetoxy derivative 2 (45percent).Treatment of 5α,6β-bromide 12, an intermediate of the acetoxylation reaction, with silver acetate also produced the acetates 2,4,5,and 8 in relative yields similar to those above.These results indicate that the 6=acetates 4 and 5 are produced through a competing pathway involving formation of a bridged carbonium ion 13 followed by attack of an acetate anion.Oxidation of the axial allylic alcohol, 5-en-4β-ol 3, with Jones reagent yielded no trace of the previously reported androst-5-ene-4,17-dione (18) but instead gave a 1:4 mixture of 5β,6β-epoxy-4-one 16 and 4β,5β-epoxy-6-one 17 in high yield.In contrast, a 1:4 mixture of androst-4-ene-6,17-dione (10) and compound 18 was obtained upon treatment with chromium trioxide in pyridine.Similar results were also found with the oxidation of another axial allylic alcohol, 4-en-6β-ol 7. (Steroid 60:499-505, 1995)
Studies Directed towards a Mechanistic Evaluation of Aromatase Inhibition with 4-Androstene-3,6,17-trione: Its Reactions with Thiols
Numazawa, Mitsuteru,Tsuji, Masachika,Osada, Ryoko
, p. 718 - 734 (2007/10/02)
Reactions of 4-androstene-3,6,17-trione (1) with thiols under various conditions are described.Treatment of (1) with ethanedithiol in MeOH in the presence or absence of BF3*Et2O gave principally a 3,3-dithioacetal (2) or a 3α,4α-ethylenedithio adduct (5), respectively.The reaction of (1) with EtSH in MeOH gave a 5α-reduced compound (9), a 3,3-diethyldithioacetal (10), a 6-methoxy-4,6-diene-3,17-dione (11), and a 4α-ethylthio adduct (12).Under p-TsOH-acidic conditions, (10) and (11) were obtained in modest yields.In contrast, (12) was isolated as the sole product under NaHCO3-basic conditions.Furthermore, (1) reacted with N-acetyl-L-cysteine uner basic conditions to yield a 1,4-adduct, sodium N-acetyl-S-(3,6,17-trioxo-5α-androstan-4α-yl)-L-cysteinate (17) along with (9).
