Abstract Diazotized anthranilic acid and its methyl ester react with ethyl α- selenocyanatoacetate 3a and α-selenocyanatoacetoacetanilide 3b to give in both cases the corresponding 1, 3, 4-selenadiazolo [2, 3-b] quinazoline derivatives 7a and 7b, respectively, in good yields (70-80%). A mechanism is proposed and it is substantiated by an alternate synthesis of 7a and 7b from the corresponding hydrazidoyl chlorides 9a and 9b with ...