Concise Two-Step Solution Phase Syntheses of four novel Dihydroquinazoline scaffolds.

Novel two-step solution phase protocols for the synthesis of dihydroquinazolines and fused dihydroquinazoline-benzodiazepine tetracycles are reported. The methodology employs the Ugi reaction to assemble desired diversity and acid treatment enables ring closing transformations. The protocols are further facilitated by the use of microwave irradiation and n-butyl isocyanide to control the rate of each ring forming transformation.