REGIOSPECIFIC ELECTROPHILIC SUBSTITUTION OF AMINOQUINAZOLINONES - DIRECTED LITHIATION OF 3-(PIVALOYLAMINO)-2-METHYLQUINAZOLIN-4(3H)-ONES AND 3-(ACETYLAMINO)-2-METHYLQUINAZOLIN-4(3H)-ONES

The 2-methyl group in 3-(pivaloylamino)- and in 3-(acetylamino)-2-meth ylquinazolin-4(3H)-ones has been lithiated with butyllithium. The lith ium reagents thus obtained react with a variety of electrophiles (benz ophenone, methyl iodide, D2O, cyclohexanone, acetophenone, phenyl isoc yanate) to give the corresponding substituted derivatives in very good yields. The amide group has been cleaved in good yield under basic co nditions for one model case to provide convenient access to 3-amino-2- ethylquinazolin-4(3H)-one. The NMR spectra of the 2-substituted 3-acyl aminoquinazolin-4(3H)-ones show diastereotopism of the CH2 group at po sition 2.