Solid-Phase Synthesis of 3,4-Dihydroquin-azolinones

Significance

In this report, the solid-phase ­synthesis of 3,4-dihydroquinazolinones from 4-methylbenzhydrylamine (MBHA) resin 1 is described. Thus, the reaction of MBHA resin 1 and 2-nitrobenzoic acids gave 2-nitrobenzamides 2. Reduction of the aromatic nitro group followed by amidation afforded the corresponding amides 4. The amides 4 were reduced with BH₃×THF and then treated with piperidine. The resulting diamines 5 were converted into the cyclic products 6, which were released from the resin to give the N-substituted dihydroquinazolinones 7.