Substituted benzoquinazolinones. Part 2: Synthesis of amino-, and sulfanyl-derivatives of benzo[f]- and benzo[h]quinazolinones

Amino- and sulfanyl-derivatives of benzoquinazolinones 16a-c, 20a-c and 21a-c were prepared under palladium-catalyzed Buchwald-Hartwig coupling reaction using bromobenzoquinazolinones 15, 19a, 19b and 1-substituted piperazines or mercaptans. The combination of Pd(OAc)2 with XantPhos proved to be the best for these conversions in the presence of KOt-Bu, in 1,4-dioxane as a solvent, at 90-100 °C.The 8-bromobenzo[f]quinazolin-1(2H)-one 15 was synthesized via condensation of the ethyl or tert-butyl 2-amino-8-bromonaphthalene-1-carboxylate 6, 10 with formamide, followed by reaction with 3,4-dimethoxybenzyl bromide. However, the 6-bromobenzo[h]quinazolin-4(3H)-ones 19a, 19b were prepared from ethyl 4-bromo-1-[(tert-butoxycarbonyl)amino]naphthalene-2-carboxylate (17).Biological screening of the potential cytotoxicity of compounds 16a, 20a, 20c on HT29 and HCT116 cell lines, has shown that compound 20a has a significant anticancer activity.