A series of 1,5-arylodiazepin-2-ones is prepared by the condensation o
f the appropriate o-beta-arylenediamines with beta-ketoesters in xylen
e under microwave irradiation. The reaction time is shortened to 10 mn
, and the products are obtained in high yields. No by products are obs
erved. Specific effects of microwaves are evidenced as no reaction occ
urs by classical heating in the same conditions.