Synthesis of 3,5‐Disubstituted‐4,5‐dihydroindeno[1,2‐ c ] [1,2]diazepin‐6(1 H )‐ones

3,5‐Disubstituted 4,5‐dihydroindeno[1,2‐ c ][1,2]diazepin‐6 (1 H )‐ones ( 3a–g ) were obtained in 29–72% yields by condensing 2‐(substituted‐2‐acylethyl)‐1,3‐indandiones ( 1a–n ) with hydrazine. The NH group of the indenodiazepinones 3a–g is quite unreactive. Two methods based on the Michael reaction were used for preparing the acylethylindandiones 1a–n : one from 1,3‐indandione and chalcone‐type compounds and the other from 2‐benzylidene‐1,3‐indandione and acetophenones. The latter method was found more practical and of more general application.