2-Aminobenzamide reacts with not only keton radical but also carbonyl group in carboxylic acid, to form easily -N-C-N-novel ring cyclization as a result I and V. In addition, it reacts with 1, 2-cyclohexadione or benzil, whitch are both 1, 2-diketone compounds, at the both ketone radical sites to give V or VII respectively. On the reaction with dimethone, however, which has 1, 3-diketone radical, it reacted with only one carbanyl group and VI was produced. We investigated the reaction with cr-ketoester such as ethyl pyruvate and diethyl rnesoxalate. In the reaction with ethylpyruvate, amine group in 2-aminobenzamide reacted not with ketone radical but carbonyl group in ester (product VIII). On the other hand, diethyl measoxalate reacted at the ketone radical site rather than the ester site (product IX).