Synthesis of a family of 3-alkyl- or 3-aryl-substituted 1,2-dihydroquinazolinium salts and their isomerization to 4-iminium-1,2,3,4-tetrahydroquinolines
作者:José Vicente、María Teresa Chicote、Antonio Jesús Martínez-Martínez、Delia Bautista、Peter G. Jones
DOI:10.1039/c0ob00982b
日期:——
A straightforward synthesis of substituted 1,2-dihydroquinazolinium triflates (3) is reported by reaction of 2-imino-substituted anilines with a range of carbonyl compounds in the presence of triflic acidvia intermediate iminium salts. Similar reactions with di- or trialdehydes and triflic acid give bis- or tris-(1,2-dihydroquinazolinium) salts. Some 4-methyl substituted 1,2-dihydroquinazolinium salts
据报道,在三氟甲磺酸存在下,通过中间体亚胺盐,2-亚氨基取代的苯胺与一定范围的羰基化合物反应,可直接合成取代的1,2-二氢喹唑啉三氟甲磺酸酯(3)。与二醛或三醛和三氟甲磺酸得到双或三(1,2-二氢喹唑啉)盐。一些4-甲基取代的1,2-二氢喹唑啉鎓盐在各种条件下重排为它们相应的4-亚氨基-1,2,3,4-四氢喹啉鎓异构体(7)。源自酮的大多数盐3都相当不稳定,这会阻止它们的分离或完全表征。已经确定了各种3和7种盐的晶体结构。