An alternative route has been developed for the synthesis of [1,4]diazepino[3,4-b]quinazolones (2), a new ring system of heterocondensed quinazolones. 2,3-Bifunctional quinazolones (4) were synthesized by halogenation of 2-alkyl-quinazolone-3-propionic acids, yield from the reaction of 2-alkyl-benzoxazone (3) with beta-alanine. The reaction of haloalkyl compounds (5,6) with N-nucleophiles produces [1,4]oxazepino-[3,4-b]quinazolones (8), a new heterocyclic ring system, and 3-[2'-hydroxi-ethyl-, or 3-[2'-chloro-ethyl-4' oxo(3'H)-quinazoline-3'-yl]propionamides (7, 9) in consecutive reaction. The cyclisation of 2-aminoalkyl-3-propionates (13) resulted in the title compounds (14). Physical data and properties of the newly synthesized compounds such as IR, UV and NMR spectra were obtained for all compounds reported.