Abstract 3, 4-Dihydro-1H, 6H-[1, 4] oxazino [3, 4-b] quinazolin-6-one 3 and its 1-methyl and 1-hydroxy derivatives 8 and 13 were prepared by different routes. The active methylene group of compound 3 was reacted with electro-hilic reagents (bromine, phenyldiazonium chloride, nitrous acid, a Vielsmeier-Haack reagent, aromatic aldehydes and diethyl oxalate) to yield 1-substituted-3, 4-dihydro [1H, 6H)-1, 4-oxazino [3, 4-b] quinazo-lin-6-ones. The ...
