Cycloaddition of Acyclic Nitrones with Phenyl Isocyanate: Synthesis and Ring‐Opening Reactions of 1,2,4‐Oxadiazolidin‐5‐ones
作者:Necdet Coşkun、Aydın Parlar
DOI:10.1080/00397910500501466
日期:2006.5
unsubstituted or electron‐donating substituents on the C‐phenyl 1a,c,f with phenyl isocyanate proceeds smoothly for a short time with high yields to give the corresponding 1,2,4‐oxadiazolidinone 2, and 1b,d,e with electron‐withdrawing substituents gave the corresponding oxadiazolidinone in moderate yields after prolonged heating. Oxadiazolidinones 2a,c,f undergo diethylamine‐induced fragmentation for a short
摘要 C-苯基 1a,c,f 上带有未取代或给电子取代基的硝酮与异氰酸苯酯在短时间内顺利进行环加成反应,得到相应的 1,2,4-恶二唑烷酮 2 和 1b,带有吸电子取代基的 d,e 在长时间加热后以中等产率得到相应的恶二唑烷酮。恶二唑烷酮 2a,c,f 会在短时间内经历二乙胺诱导的碎裂,得到相应的席夫碱,而恶二唑烷酮 2b,d,e 在这些条件下保持不变。在二乙胺存在下长时间加热 2d,e 导致复杂的混合物。在 2b 的情况下,相应的脒是反应的主要产物。