Through an optimised Pd/Cu-catalysed cross-coupling reaction of 4-iodopyrazoles with 2-propyn-1-ol, followed by Mitsunobu transformation with N-hydroxyphthalimide and subsequent hydrazinolysis, O-[(pyrazol-4-yl)-prop-2-ynyl]-hydroxylamines were obtained in good yields. Their usefulness as intermediates in the synthesis of pharmaceuticals is exemplified by the first reported intramolecular cyclization of O-(2-propynyl)-hydroxylamines to yield 4,5-dihydro-isoxazoles.
通过优化Pd/Cu催化的
4-碘吡唑与
2-丙炔-1-醇的交叉耦合反应,随后进行 Mitsunobu 转化与 N-羟基邻苯二甲
酰亚胺反应,并经后续
肼解,以良好产率得到了O-[(
吡唑-4-基)-丙-2-炔基]-
羟胺。这些化合物作为药物合成中间体的实用性,通过首次报道的 O-(2-
丙炔基)-
羟胺的分子内环化反应生成4,5-二氢
异噁唑得以体现。