Bicalutamide, a therapeutically important anti-androgen used in the treatment of hormone-sensitive cancers, may be synthesised from the appropriate halohydrin or epoxide. We report here studies aimed at demonstrating unambiguously that preparation of bicalutamide and its thioether analogue from the chlorohydrin under basic conditions proceeds via opening of an intermediate epoxide by the appropriate sulfinate or thiolate nucleophile, that the analogous anionic sulfur nucleophiles react under the same conditions and that the SN2 pathway involving direct displacement of chloride by the nucleophile does not operate. The proposed mechanism is confirmed by the quantitative fitting of sequential reaction kinetics, taking into account the competing dimerisation of the thiolate nucleophile that occurs under basic conditions. The O-methyl analogue of the chlorohydrin is unreactive towards thiolate under the same conditions, although a slower cyclisation to the β-lactam was observed. The implications of these observations for the analogous preparation of thioethers and sulfones are discussed.
比卡鲁胺是一种在治疗激素敏感癌症中具有重要疗效的抗雄激素,可能由适当的卤醇或
环氧化物合成。我们在此报告了研究,旨在明确表明在碱性条件下,从
氯醇制备
比卡鲁胺及其
硫醚类似物的过程是通过适当的亚
磺酸盐或
硫醇核烯开环中间
环氧化物进行的,类似的阴离子
硫核烯在相同条件下也会发生反应,并且涉及核烯直接取代
氯离子的SN2途径并不适用。所提机制通过考虑在碱性条件下发生的竞争性
硫醇核烯二聚化的量化反应动力学拟合得到确认。在相同条件下,
氯醇的O-甲基类似物对
硫醇核烯不反应,尽管观察到了较慢的环化反应生成β-内酰胺。这些观察对
硫醚和磺酮的类似制备的影响进行了讨论。