A series of methyl [3-alkyl-2-(2,4-dioxo-3,4-dihydro-2H-quinazolin-1-yl)-acetamido] alkanoate 10-13a-f has been developed on the basis of the N-chemoselective reaction of 3-substituted quinazoline-2,4-diones 3a-d with ethyl chloroacetate and azide coupling method with amino acid ester hydrochloride. The precursor quinazoline diones 3a-d chemoselective reactions were studied using DFT(B3LYP)/6-311G level of theory and were prepared by a new rearrangement method from the corresponding 2-(3-methyl-4-oxo-3,4-dihydroquinazolin-2-ylthio) acetohydrazide 6.