Acid-promoted reactions in 1-hydroxy, 1-dimethylaminomethyl and 1-methylene-4-arylmethyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-diones
作者:Marı́a Luisa Heredia、Elena de la Cuesta、Carmen Avendaño
DOI:10.1016/s0040-4020(02)00619-1
日期:2002.7
The 1-dimethylaminomethyl or 1-methylene group of the title compounds was introduced through a Mannich or a tandem of Mannich–Hofmann reactions as the final step of a protocol that is shorter than other previously described for these precursors of N-acyliminium species. In these compounds, the acid-promoted intramolecular cyclizations of Pictet–Spengler-type were restricted to the N(2)-unsubstituted
通过曼尼希或串联曼尼希-霍夫曼反应引入标题化合物的1-二甲基氨基甲基或1-亚甲基,作为该方案的最后一步,该步骤比先前针对这些N-酰基species属物种的其他前者所描述的要短。在这些化合物中,Pictet-Spengler型的酸促进分子内环化作用仅限于N(2)-未取代的化合物,而它们的N(2)-甲基取代的类似物却提供了二聚化产物。通过将格氏试剂添加到2 H,4 H-吡嗪并[ 2,1 - b ]喹唑啉-1,3,6-三酮中可以得到1-羟基-1,2-二取代的化合物,该环化反应是有效的。