Nitrogen bridgehead compounds. Part 88 . Synthesis of 3 H , 7 H ‐[1,4]diazepino[3,4‐ b ]quinazoline‐3,7‐diones

3 H ,7 H ‐[1,4]Diazepino[3,4‐ b ]quinazolone‐3,7‐diones 9, 11 were synthesized starting from 2‐(1‐bromo‐ethyl)quinazolin‐4(3 H )‐ones 3 and 17 via 2‐[1‐(4‐methoxyphenylamino)ethyl]quinazolin‐4(3 H )‐ones 4 and 18. Cyclization of 3‐[2‐(1‐bromoethyl)‐4‐oxo‐3,4‐dihydroquinazolin‐3‐yl)propionic acid 14 by the action of triethylamine provided the first representative of the tricyclic 7 H ‐[1,4]oxazepino[3,4‐ b ]quinazoline‐3,7‐dione system, compound 15. The new tricyclic derivatives 9, 11 and 15 are characterized by uv, ir and 1 H nmr spectroscopy.