The efficient catalytic action of polyphosphoric acid, when used in the presence of alkylmercaptans as nucleophiles, of normal ring opening of 17β-acetoxy-4, 5-epoxyandrostan-3-one (VII), was reported. With ethanethiol in PPA-dioxane at room temperature, VII afforded 4-ethylthio-17β-acetoxyandrost-4-en-3-one(VIII), and a further product, 17β-acetoxy-3, 4-bis(ethylthio)androsta-3, 5-diene (IX), accompanied by the third product with a transparent ultraviolet spectrum, the structure of which was tentatively assigned as 4β-ethylthio-5α-hydroxy-17β-acetoxy-5α-androstan-3-one (X). Ethanedithiol and 2-mercaptoethanol also reacted with VII, as expected, affording 17β-acetoxyandrosta 3, 5-dieno [3, 4-b]dithiane (XI) and its oxathiane (XII) derivative respectively. Unique ultraviolet absorption data of the dithiane (XI) and oxathiane (XII) was referred to in connection with the suggestion of presence of some unique conjugation in the -S-C3=C4-S- and -O-C3=C4-S- systems in these compounds.
据报道,在有烷基
硫醇作为亲核物的情况下,聚
磷酸可高效催化 17β-acetoxy-4, 5-epoxyandrostan-3-one (VII) 的正常开环。室温下,在
PPA-
二氧六环中加入
乙硫醇,VII 得到 4-乙
硫基-17β-乙酰氧基
雄甾烷-4-烯-3-酮(VIII)和另一种产物 17β-乙酰氧基-3,4-双(乙
硫基)雄甾-3,5-二烯(IX),同时还得到第三种具有透明紫外光谱的产物,其结构暂定为 4β-乙
硫基-5α-羟基-17β-乙酰氧基-5α-
雄甾烷-3-酮(X)。乙二
硫醇和
2-巯基乙醇也如预期那样与 VII 发生反应,分别生成 17β-乙酰氧基
雄甾烷-3,5-二烯并[3,4-b]二噻烷(XI)及其氧
硫烷烃(XII)衍
生物。二噻烷(XI)和氧
硫杂
环己烷(XII)独特的紫外吸收数据被认为与这些化合物中 -S-C3=C4-S- 和 -O-C3=C4-S- 系统中存在的某些独特共轭有关。