Intermolecular and Intramolecular Diels−Alder Cycloadditions of 3-Ylidenepiperazine-2,5-diones and 5-Acyloxy-2(1<i>H</i>)-pyrazinones
作者:Shangde Jin、Pablo Wessig、Jürgen Liebscher
DOI:10.1021/jo0100897
日期:2001.6.1
Diels-Alder reactions of alkenes and alkynes to the piperazine ring, under acidic conditions or in the presence of acetyl chloride, to afford tricyclic piperazine-2,5-diones 19, 20, 23-25, 27, 44, and 45. Intramolecular cycloadditions occur if 3-ylidenepiperazine-2,5-diones 30 and 32 are used as the starting materials. This procedure is a convenient path to bridged bicyclo[2.2.2]diazaoctane ring systems such
3-亚烷基哌嗪-2,5-二酮16和39和5-酰氧基-2(1H)-吡嗪酮17可以用作烯烃和炔烃在酸性条件下或在酸性条件下Diels-Alder反应的原料。存在乙酰氯,得到三环哌嗪-2,5-二酮19、20、23-25、27、44和45。如果使用3-亚苯基哌嗪-2,5-二酮30和32作为分子,则发生分子内环加成。起始材料。此程序是连接双环[2.2.2]二氮辛烷环系统(例如31和33)的便捷途径,前者存在于具有生物活性的二次霉菌代谢产物中,例如VM55599(1)或brevianamide A(5)。从各种真菌中分离出来。吲哚化合物31的合成为拟议的以Diels-Alder反应为关键步骤的生化途径提供了证据。