Synthesis of Eleven-Membered Cyclic Urea Fused Quinazolinones.

Straightforward synthesis of quinazolinones having N-fused medium-sized ring urea was accomplished. Key intermediates were tert -butyl {2-[4-oxo-2-(4-oxopentyl)quinazolin-3(4 H)-yl]ethyl}carbamates derived from copper-catalyzed domino reaction of tert -butyl [2-(2-iodobenzamido)ethyl]carbamates and cyclic enaminones. Steric hindrance of cyclic enaminones played an important role in the formation of quinazolinone ring. The eleven-membered ring urea moiety was readily achieved by direct cyclization using 1,1′-carbonyldiimidazole (CDI) of diamino intermediate generated by readily reductive amination and deprotection of tert -butyl {2-[4-oxo-2-(4-oxopentyl)quinazolin-3(4 H)-yl]ethyl}carbamates. [ABSTRACT FROM AUTHOR]