A One-Dimensional Thorium-Containing Arsenotungstate for the Synthesis of 2,3-Dihydroquinazolinones.

A novel one-dimensional chain thorium-containing arsenotungstate, H12[(Th2W3O10)(AsW9O33)2(H2O)6]·14H2O (Th2As2W21), has been successfully synthesized. Th2As2W21 consists of a {Th2W3} unit that connects two {AsW9} units to form a dimer. Adjacent dimers are linked through two Th-O-W bonds, resulting in an interesting wavy one-dimensional chain. Notably, the incorporation of Th4+ endows Th2As2W21 with remarkable Lewis acidity, enabling it to function as an efficient heterogeneous catalyst for the condensation-cyclization reaction between 2-aminobenzamide and aldehydes to afford 2,3-dihydroquinazolinones. Under environmentally friendly and mild conditions, a series of 2,3-dihydroquinazolinones was obtained in excellent yields (up to 98%). This study not only enriches the structural diversity of thorium-containing polyoxometalates but also provides a promising heterogeneous catalyst for the sustainable synthesis of N-heterocycles.