Abstract Diazotized anthranilic acid and its methyl ester react with substituted phenacyl thiocyanates 3 to give in both cases the corresponding thiadiazolo [2, 3-b] quinazolines 7a- e. A mechanism is proposed and it is substantiated by alternate synthesis of 7a from the hydrazidoyl chlorides 9a, b and potassium thiocyanate.
![2-[2-(1-chloro-2-oxo-2-phenylethylidene)hydrazinyl]benzoic acid Structure](https://image.chemsrc.com/caspic/188/82000-25-7.png)