The syntheses of two AB2 monomers, aminodicarboxylic acid (1) and aminodicarbonyl azide
(2), and their model reactions for the one-pot synthesis of dendritic aromatic poly(urea-amide)s using the
two AB2 monomers were carried out. The model reaction of 2 and p-tolyl isocyanate produced the target
urea with two acyl azide groups in 93% yield at 25 °C for 30 min in tetrahydrofuran (THF). The Curtius
rearrangement from an acyl azide to an isocyanate was completed at 140 °C for 30 min in THF. The
isocyanate produced via the Curtius rearrangement readily reacted with aniline to give a urea compound
in 93% yield. p-Tolyl isocyanate selectively reacted with an amine group of 1 to give a urea with end
carboxylic acid groups. The end carboxylic acid groups of the urea could be activated with a condensing
agent, diphenyl(2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (DBOP), and the condensation of the
active amide with 2 provided an amide with acyl azide end groups.