LITHIATION OF -(ACYLAMINO)-2-UNSUBSTITUTED-4(3H)-QUINAZOLINONES, 3-(ACYLAMINO)-2-ETHYL-4(3H)-QUINAZOLINONES, AND 3-(ACYLAMINO)-2-PROPYL-4(3H)-QUINAZOLINONES - CONVENIENT SYNTHESES OF MORE COMPLEX QUINAZOLINONES

3-(Pivaloylamino)- and 3-(acetylamino)-4(3H)-quinazolinones react with alkyllithium reagents to give 1,2-addition products in very good yiel ds. Lithiation takes place with LDA and is regioselective at position 2. The lithium reagents thus obtained react with a variety of electrop hiles to give the corresponding substituted derivatives in very good y ields. Reactions of the lithium reagents with iodine give oxidatively dimerized cyclic structures. 3-(Pivaloylamino)- and 3-(acetylamino)-2- ethyl-4(3H)-quinazolinones and 3-(pivaloylamino)- and 3-(acetylamino)- 2-propyl-4(3H)-quinazolinones are lithiated at the benzylic position w ith LDA. The lithium reagents so produced also react with a variety of electrophiles to give the corresponding 2-substituted-4(3H)-quinazoli none derivatives in very good yields. However, lithiation of (acylamin o)-2-(1-methylethyl)-4(3H)-quinazolinones was unsuccessful, as were li thiations of compounds having a diacetylamino group at position 3. The amide groups have been cleaved in good yield under basic or acidic co nditions from some of the products to provide access to the free amino compounds.