Unprecedented reactivity of 3-amino-1H,3H-quinoline-2,4-diones with urea: an efficient synthesis of 2,6-dihydro-imidazo[1,5-c]quinazoline-3,5-diones

摘要

Substituted 3-amino-1H,3H-quinoline-2,4-diones react with urea in acetic acid to, give novel 2,6-dihydro-imidazo[1,5-c]-quinazoline-3,5-diones in high yields. The same compounds were obtained, albeit with small yields, from 3-chloro-1H,3H-quinoline-2,4-diones and urea. In the proposed reaction mechanism, a molecular rearrangement of the primarily formed mono-substituted urea takes place. The prepared 2,6-dihydro-imidazo[1,5-c]-quinazoline-3,5-diones were characterized by their H-1, C-13, N-15 NMR and IR spectra and atmospheric pressure chemical ionisation mass spectra. (C) 2003 Elsevier Science Ltd. All rights reserved. [References: 9]