Synthesis of isomeric angularly fused dihydroquinazolinoquinazolinones and an unusual oxidative rearrangement

Cyclization of 2-(2-aminophenyl)-2,3-dihydroquinazolin-4(1H)-ones onto N1-nitrogen and onto N3-nitrogen leading to 11b,12-dihydro-(13H)-quinazolino[3,4-a]quinazolin-13-ones and 13,13a-dihydro-(8H)-quinazolino[4,3-b]quinazolin-8-ones, respectively, is described for the first time. An unusual dehydrogenative rearrangement of 11b,12-dihydro-(13H)-quinazolino[3,4-a]quinazolin-13-one to (8H)-quinazolino[4,3-b]quinazolin-8-one is also described.