An efficient, environmentally benign,
and inexpensive procedure
has been developed for the synthesis of fluorinated 2-alkylthio-4-aminoquinazolines
by microwave irradiation using basic alumina as a solid-support agent
as well as a solid base. Notably, this protocol features improved
energy efficiency, broad isothiourea substrate scope, easily available
starting materials, and high atom efficiency and applicability toward
gram-scale synthesis. Additionally, the target compounds were evaluated
for the cytotoxic effect against human colon adenocarcinoma (HCT116
and HT29), human gastric cancer (SGC-7901), human lung adenocarcinoma
(A549), and human hepatocyte carcinoma (HepG2) cells, and it was found
that these compounds have excellent antitumor activities. Among them,
compound 3e was found to be one of the most potent derivatives
with IC50 values lower than 9.44 μM against five
human tumor cell lines, making it more active than cisplatin (DDP).
Furthermore, for the first time, the fluorinated 2-alkylthio-substituted
4-aminoquinazolines were identified as phosphatase CDC25B inhibitors.