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。