2-Methylquinazolin-4(3H)-one has been doubly lithiated, at nitrogen and in the 2-methyl group, with n-butylithium. The lithium reagent thus obtained reacts with a variety of electrophiles (iodomethane, D2O, phenyl isocyanate, benzaldehyde, benzophenone, cyclopentanone, 2-butanone, carvone) to give the corresponding 2-substituted derivatives in very good yields. Reaction of the dilithio reagent with acetonitrile gives an α,β-unsaturated imine by tautomerization of the initial addition product. Double lithiation of 2-ethyl- and 2-propyl-4(3H)-quinazolinones can be achieved using lithium diisopropylamide and the lithiated reagents thus obtained react with similar electrophiles to give the corresponding products in very good yields. In the reaction of the dianion of the 2-ethyl-4(3H)-quinazolinone with iodine, an oxidatively dimerised product was obtained. Lithiation of 2-unsubstituted 4(3H)-quinazolinone does not take place on C-2 under similar conditions.
2-甲基喹唑啉-4(3H)-酮已被丁基
锂双
锂化,在氮原子和2-甲基基团上发生了反应。因此获得的
锂试剂与各种亲电试剂(
碘甲烷、D2O、苯
异氰酸酯、
苯甲醛、苯甲酮、
环戊酮、2-
丁酮、
香茅酮)反应,产率非常高,得到相应的2-取代衍
生物。用
乙腈与二
锂试剂反应,通过最初加成产物的重排生成α,β-不饱和
亚胺。使用
异丙基胺锂对2-乙基和2-丙基-4(3H)-
喹唑啉酮进行双
锂化,获得的
锂试剂与类似的亲电试剂反应,产率非常高。2-乙基-4(3H)-
喹唑啉酮的二负离子与
碘反应时,会得到氧化二聚产物。在类似条件下,2-未取代的4(3H)-
喹唑啉酮的
锂化不会发生在C-2位置。