as the dienophile. The dienes were prepared from thiophene in two steps by addition to various ketones, followed by dehydration (40–60% overall yields). Although most dienes were obtained as regioisomeric mixtures, the Diels–Alder‐derived products were easily purified by chromatography. The main cycloaddition pathway was endo Diels–Alder addition followed by exo ene addition of a second molecule of
在我们之前有关
吲哚和
吡咯的研究的扩展中,使用N-苯基马来
酰亚胺作为双亲物,探索了取代的
2-乙烯基噻吩的Diels-Alder
化学。由
噻吩分两步制备二烯,方法是先加入各种酮,然后进行脱
水(总收率为40-60%)。尽管大多数二烯是作为区域异构体混合物获得的,但Diels–Alder衍生的产品很容易通过色谱法纯化。主要的环加成途径是内Diels–Alder加成,随后是外切烯添加第二个亲二烯体分子(产率19-33%)。几种产品用阮内
镍脱
硫(收率48-62%)。不幸的是,没有
噻吩衍生的产品显示出以前报道的
吲哚类似物有希望的
生物活性。